Pivski Bender

Good news, everyone! Here is a story about building my very own Bender. This, as everyoneshould know, is the foul mouthed, cigar smoking, booze drinking, shiny metal arsed, bending

robot from the programme Futurama. More information can be found in the Wikipedia Futuramaentry .Of course just having a Bender that doesn't do anything would be a waste of time so mine shallbe used for a practical purpose. One Bender himself would be proud of. I'll use him to makebeer! This was actually done in the show in the episode "The Route of all Evil". The idea wassuggested to me by my drinking buddy Dave. I didn't remember this until he provided the proof(typos and all):[3/30/2007 9:21:20 AM] Simon Jansen says: Everytime I watch Futurama I want to build a bender.[3/30/2007 9:24:14 AM] David Moore says: do you remember the episode where they brew beer inside Bender?[3/30/2007 9:24:26 AM] David Moore says: you should build that.... a Bender brewer[3/30/2007 9:24:28 AM] Simon Jansen says: Vaguely.\[3/30/2007 9:24:37 AM] David Moore says: he gets all maternal[3/30/2007 9:24:42 AM] Simon Jansen says: I could buil done out of real steel.[3/30/2007 9:26:49 AM] David Moore says: season3 episode12: The Route of All Evil[3/30/2007 9:26:56 AM] David Moore says: title refers to money, not beer[3/30/2007 9:27:27 AM] Simon Jansen says: How about a Bender beer fridge? Get one of those mini fridges andbuild that into him?[3/30/2007 9:28:00 AM] David Moore says: no a brewerSo, credit where credit is due!In addition to this my Bender shall talk thanks to his very own brain. A brain, again as specifiedin the show in the episode "Fry and the Slurm Factory", made from a real MOS 6502 processor.This processor powered some of the great early computers such as the Vic 20 and the Apple 2(both of which I have owned at some point). What follows is how to go about doing this. Benderis not yet complete but I shall explain what I have so far and add more as he is completed.The first problem was figuring out what Bender looks like. Of course everyone knows what helooks like right? This is true but Bender is a cartoon character and trying to make a 2dimensional character into a real, believable thing isn't easy. You only have to look at Anakin theManikin from the new Star Wars films to see that! I started by watching as many episodes ofFuturama as possible then searching the net for pictures. Then I started making my owndrawings of Bender. I certainly didn't get every detail exactly right but I think he is sufficientlyBender like to be instantly recognisable. I had to do a best guess at Benders height but to the topof his antenna he seems to be about 6 feet tall. In the episode "The Cyber House Rules" we getto see a mug shot of Bender that also shows his height to be about 6 feet. The body dimensionswere chosen to look about right and so that my beer brewing barrel would be able to fit inside thebody. When I have built other props and models in the past they have always been actualobjects to start with. You can often find real dimensions to work with or else work them outyourself from photographs and screen shots. You can't easily do that from a cartoon. From myfirst rough sketches I started drawing more detailed plans taking into account how I wouldphysically build him. I then transferred these small drawings onto a piece of paper taped to theback of a door. This allowed me to draw Bender full size to make sure the proportions lookedright. I did need to tweak my dimensions a little still but I finally got him looking about right. Or soI thought.

Figure 1. The door plan, router circle jig, cutting circles with thejig.Once I had the basic shape figured out I had to start thinking about how to physically build him.This is the part I like best. I decided to use a building style I had tried once before on a stillunfinished R2D2 I was making. The basic frame is made from rings of MDF with round dowels tohold them together and provide a frame. On R2 I had planned to wrap the body in white styrenesheet. I decided to make Benders body a little differently. I used cardboard as a covering that isthen overlayed in fibreglass. Because Benders body is smooth this should work rather well. Hislegs are straight as he has to take the weight of a beer brewing barrel on them. The body, headand shoulders and arms can all be very light weight.The body base and top (and feet and head) are circular so I needed a way to cut nice circlesfrom the MDF. The way to do this is to make a jig to hold a plunge router and use this to makethe circular cuts. The jig is simply another piece of MDF with the router bolted onto one end anda hole for a pivot somewhere on it. Obviously by changing the pivot point you can change thesize of the circles cut. Since Benders body tapers and I needed to attach vertical dowels to theoutside of it I had to make the cuts on the top and bottom of the body with a taper. To do this yousimply mount the router on the jig at an angle. From my full size door drawing and with a littletrigonometry I was able to measure the angle needed and set the router up appropriately. I cutthe first discs and made Benders body by then screwing lengths of dowel to the outside of thediscs. You need to make sure the two discs are both centered correctly but a few pieces ofscraps timber as a temporary frame and a plum bob allowed me to do this. Once I hadcompleted the body I discovered I'd had a visit from Mr. Cock-up and mangled the angle ofBender's dangle! I had made the body too tapered. So, like any good perfectionist, I threw thatone away and made another. I modified the shape slightly to make the body more cylindrical andI also tweaked the height and width. The new body came out looking much nicer.

Figure 2. Routed rings (with dead squished Weta), feet and legdetails.Once the body frame was done I made the shoulders and head. The head is simple. It's just tworings of MDF with dowels making up the sides to form a cylinder. The dome on top is addedlater. The shoulders are a little trickier. The lower part is another ring of MDF with the correcttaper for the shoulder cut into it. Leading up from these are dowels cut on an angle. Thesedowels go up to an upper ring that is the same diameter as the bottom of the head. The head andshoulder parts are designed to lift off the body so you can get to the beer brewing barrel inside.Even though the body does have a door on the front (which shall be made from thin car steel)this isn't a big enough opening to get the barrel in and out. The door opening sides are formed bythe wooden framing dowels. The top and bottom of the door frame are made from curved piecesof MDF. I used a Dremel tool to cut round notches into the ends of these pieces so they will fittightly against the round vertical dowels. They are then glued into place. The legs and feet wereagain made from wood. The feet are made from two discs of MDF held together in the middlewith a steel strap across the top of them. The legs are made from two straight pieced of timbersimply glued and screwed to the round foot base. As mentioned they are perfectly straight sothat the weight of the beer inside him is transferred straight down to the feet.

Figure 3. Feet domes, frame, shoulder and head detail.The domes for the eyes, head and feet are polystyrene balls cut in half with a hot wire. Thewire is nichrome resistance wire from the local electronics shop. I simply held two pieces ofwood in the vice in a V shape and strung the wire tightly across them. A battery charger suppliedthe current. The size of Benders feet and head was carefully chosen so that I could get thespheres in the exact sizes I needed. I am also using cut up polystyrene spheres for theshoulders. One sphere was cut in half to make the feet. A hole was made in each half so theycould slide down over the wooden legs. Then the 80mm diameter PVC down pipe was slid downover the top of the legs. The legs were then screwed and glued to the base of the body. Thedome on the top of the head was another half sphere of polystyrene glued to the top of the headcylinder. Before fibreglassing using polyester resin you have to seal the polystyrene otherwisethe resin will eat it away! To seal the polystyrene away I used several techniques (I make thisstuff up as I go along so it's all trial and error) and they all seemed to work well. The feet Icovered in several layers of Papier-mch. I then used a thick acrylic house paint to seal overthat. For the head I used aluminium foil glued over the dome then again multiple layers of acrylicpaint. I suspect just using paint would have been enough as long as there are enough layers tocompletely seal the dome.

Figure 4. Covering the frame and insulating.Once the legs were attached I could cover the body. The body is actually double skinned as Iglued thin card to both the inside and outside of the frame. Between the two layers I used quiltingmaterial as insulation. The idea being it should be easier to keep Benders internal temperatureconstant which I think is better for when the beer is brewing inside him. The shoulder part is alsocovered in thin card. The shoulders will actually be finished off last as I want to build the base ofthem up to exactly fit the outline of the top of the body. This should give Bender a nice even joinbetween the body and the shoulders. Small wooden dowels will be used as locating pinsbetween the head and shoulders and the shoulders and body. The head was also covered inthin cardboard and the eyes made up from cardboard with another polystyrene sphere cut in halffor the actual eyes. Again these were sealed with glued on foil and layers of acrylic paint. Theantenna, added after the head was fibreglassed, was kindly made for me by a skilled woodturner. Actually I don't know that this particular piece taxed his skills much as it only took him afew minutes to make! The bottom of the antenna was glued into a hole in the top of Bendershead. The polystyrene of the dome was drilled out and we also bored a hole right down thecentre of the wooden antenna. Through these holes I run a wire to a ultra bright red LED. TheLED is stuck into an opaque plastic sphere at the top of the antenna which lights up redwhenever Bender's remote is used. The sphere is the ball from a roll on deodorant andhappened to be almost exactly the right size!

Figure 5. Foiling and painting (yes, and unfortunate beer tapplacement).Once all the cardboard was in place I covered everything in layers of fibreglass. I am usingpolyester resin (instead of epoxy resin) since it is cheap and easy to work with. If you need toadd more layers later you can just lay them on over what you have already done. I am usingwoven cloth instead of chopped strand mat as it was easier to work with over the surfaces Ineeded to cover. I applied cloth to both the inside and outside of the body and over the top of thePVC legs as it will be much easier to paint the fibreglass on the legs rather than trying to paintPVC. Only one layer was needed on the legs as there is no need for strengthening there. Thebody needed about three layers to make it sufficiently rigid. Once the fibreglass has set you canbegin trimming the excess and start sanding. This takes a long, long time and created quite a lotof dust so I did this outside wearing a good dust mask. It is work mentioning that when laying upthe fibreglass I also used a good respirator (with solvent filters) and wore gloves. You don'treally want to breathe in the fumes or let the resin contact your skin. Bender has only beenroughly sanded so far. To get him really smooth you also need to apply car body filler (we call itbogging down here in NZ) then sand that off to get a nice smooth surface to paint. It takes a lotof filler to get a nice smooth surface. You end up applying a lot then sanding most of it off againbut it is necessary to do this if you want a nice finish before painting.

Figure 6. Fibreglassing the parts.Before I finish bogging/sanding him I need to build the arms. When I started I wasn't quite surehow to make the arms. I was confident some inspiration would come to me! The first thought I(and most people) have is to use flexible ducting. This would have been good as it would allowthe arms to bend and be moveable. I decided against it for several reasons though. The firstreason was I don't think it will look correct. Benders arms and legs are smooth with five blacklines around them to highlight the sections. Flexible duct doesn't have the correct smooth shape.The second, and main reason, was simply because I couldn't get ducting the correct diameter. Ineeded something that would match the 80mm diameter of the PVC I used for the legs. I havenow decided the arms will need to be rigid (although able to rotate) and they will be made from

fibreglass over some kind of central core. The core is made from something I discovered in thelocal plastics shop and is something I have used as a former for curved mud guards on a minibike project in the past. Pool noodles! These are long tubes of foam used as flotation devices bychildren in swimming pools. They are almost exactly the right diameter and they have a holeright through the middle of them. My current plan is to use a piece of half inch copper water pipebent into the correct shape for the arms. The pool noodle will slide over the copper pipe whichwill hold it in the correct curved shape. The shoulders will be attached firmly to the body but thebase of the arms will be pivoted inside the shoulders so they arms can be rotated into differentpositions. The hands will probably be made from a cardboard or plastic former again covered infibreglass. The fingers can simply be wooden dowels.That is basically where Bender's body is at today. Since it is Winter here now and the weatherhas been somewhat unpleasant I have been spending a lot of time indoor working on the othermajor part of the Beer Brewing Bender project - the brain!

Figure 7. A tidy work space is essential, the 1541 floppy drive andit's circuit board.As I mentioned one of the geek jokes on Futurama is that Benders brain is using a 6502processor. The chip was invented in 1975 and was used in many of the early home computers.My first computer was a Commodore Vic 20 back in about 1984 and both this and the later Apple2s I owned used this processor. I thought it would be interesting to use a real 6502 processorand make my own computer from scratch and use this to make Bender talk somehow. I hadpreviously built for a circuit for an earlier Lightsabre project where a PIC 16C84 microprocessoris used to play samples stored in memory. The processor is used to control a binary counterthat simply clocks out data from the memory chip and latches it through to a simple D to Aconverter to turn it into sound. I decided I could use the same idea but with a 6502 instead of aPIC.Now a PIC is a modern processor. Basically it is an entire computer on a chip and it needs veryfew other components to get it do anything useful. A 6502 is old school though. To actually makeit do anything you need a lot of support circuitry and other chips. At a minimum you need a clock

generator, RAM, ROM and I/O (input-output) as well as a lot of logic 'glue' to make it all worktogether. I did say this project would be interesting, not simple! The specifics of the 6502computer and audio board I built deserve their own page which I shall put up soon (with circuitdiagrams and code) but here is the basic idea.When I was researching using the 6502 I came across an interesting fact. The Commodore 64,another very successful early home computer, used a variant of the 6502 (the 6510). Eventhough the C64 itself doesn't use a 6502 the 1541 floppy drive used with them did. In fact thefloppy drive contains a 6502 and all the support circuitry you need to make your own computer.As it happens I happened to have an old 1541 floppy drive sitting under my parents house aftersomeone gave it to me sometime over 10 years ago. I went and rescued it and found it was inpretty good condition. My original aim was to modify and use the drive pretty much as it was butin the end I decided to use the parts (mainly the 6502, the 2016 RAM chip and the 6522 I/O chip)to make my own, smaller single board computer. I am using pretty much the same core circuitas the 1541 drive but with only one I/O chip and with a slightly easier to find ROM chip as theoriginal 2364 EPROM is difficult to get these days.

Figure 8. My 6502 based audio and CPU board, wiring side and thewireless transmitter.Building the computer went very well. I use experimenters strip board with point to point wiringusing enameled copper wire. You can get several different types of wire but the one to be usedfor this is the kind where the red insulation can be burned off with a soldering iron. Unfortunatelywhen I was testing the circuit disaster struck! Having a somewhat messy work area Iinadvertently plugged the wrong power supply into my circuit board and immediately sent theCPU, the RAM and the I/O chip off to silicon heaven! The project came to a halt at that point aswithout the CPU and other chips I couldn't do much. I was going to look on TradeMe, the localauction web site, for a replacement 1541 drive to scavenge parts from but in the end Idiscovered a nice little site online in the states who supply old chips for people restoring old

computers and arcade games - ArcadeComponents.com. I ordered a new CPU, RAM and I/Ochip for very, very reasonable prices (actually I ordered two of each in case I had any more'accidents') and once they arrived I was able to continue.Once I knew my replacement chips were on the way I started on the audio part of the circuit. Iwanted to build this so it would be testable without needing the 6502 computer to drive it.Basically how it works is as follows. I am using old 27C2001 2Mbit x 8 EPROM chips I boughtfrom the local surplus electronics supplier. I am using three of these chips to store audiosamples in 8 bit 16kHz raw format. The circuit will support up to 10 audio ROMS but three fittednicely on the circuit board. Each chip allows me to store around 15 seconds of audio so I haveabout 45 seconds in total. The processor selects which chip is the one being played from. To getthe audio out of the chips I use a binary counter attached to the ROMs address lines. Thecounter is driven by a 555 timer based clock on the audio board. The processor can control viaan AND gate when to send the clock signal through to the counter. The output of the audioROMs is fed into a latch then into a simple R2R D to A converter. This converts the digital bitsinto an analogue signal. The signal is fed to a small onboard amplifier attached to an old PCspeaker.By resetting the binary counter and then starting the clock the circuit increments up through theROM address space clocking out samples one at a time to be converted into sound. If you startaddressing at 0 and let it keep clocking it will simply play the entire contents of the chip then looparound to the start again. That would give you 15 seconds of audio in one go. What I wanted tobe able to do was play different, shorter samples randomly so Bender can have many things tosay. The way I did this is to break the address space into separate spaces or pages. But havingthe 6502 processor be able to set the top four bits of the binary counter before you start countingyou can break each ROMs address space into 16 evenly sized blocks and you can start playingat any one. The top four bits are set on a presetable binary counter which is simply a counterthat can be set with a starting value and it will then count up from there rather than zero. Toknow when to stop playing a sample I encoded a value of 255 into the sample. Some simplelogic on the audio board can detect this value (since all 8 data bits are set) and this causes ahardware interrupt back to the processor so it knows to stop playing. To start playing I simplypoll an input on the processor I/O board. Samples may span more than one block. I built theaudio board in such a way that I could simulate the processor inputs into it and test it in standalone mode. that way I was able to build and test the audio circuit and be sure it was workingbefore finishing off the 6502 computer.

Figure 9. 6502 CPU board, audio board, remote with brain, light andwireless receiver.Once my new 6502 and other chips arrived I was able to finish building the computer. I hadmany problems to solve along the way and actually had to buy a new oscilloscope in the end tobe able to debug my circuit and code but eventually I got the computer to work. This is now allnicely interfaced with the audio board and controlling it. The code is very simple. It knows thechip and starting location of all the samples stored in the brain. In the end I recorded 15 differentBender sayings from Futurama episodes. The code simply loops around all the startingaddresses storing each one one particular memory location. Between storing each value I pollfor a input which tells me it is time to start playing. If the input is there the processor simply usesthe last starting value it stored and outputs the correct chip selection and starting address bits tothe audio board and starts the clock running. While playing other inputs are ignored but theaddresses keep looping. When playing stops it simply starts looking for another trigger signal.Because the looping of the 15 addresses is done so quickly you never know quite whichaddress it on when the play is triggered giving a more or less random selection of samples.To hear the samples stored on each of the chips click below:Chip_1_8bit.wav (241 kB)Chip_2_8bit.wav (235 kB)Chip_3_8bit.wav (251 kB)The "faith and begorrah" saying on chip two is in memory of my Irish friend Davina. No, shedidn't die. Something much worse. She went to Australia!The triggering is done by a separate circuit board. The simplest trigger is just a push button onthis board but I wanted something better than that. I wanted it to be triggered by remote controland in particular with a remote like one they used on the show. In the episode "War is the HWord" a bomb is placed inside Bender that can be activated by a remote control. I bought a verysimply ASK transmitter and receiver module which is usually used for small wireless remotesand adapted that to work as a remote control for Bender. The actual remote case has been

styled to look similar to the one in the episode. Now, with each press of a button Bender will talk.Holding the buttons down Bender just keeps talking saying random things. Also when the buttonon the remote is pressed the ball on top of his antenna lights up red. I have provision for twoother inputs to trigger the talking. I will probably put a sensor on Benders metal door and use thatas one trigger and I am undecided how (or if) I will use the other at the moment. The remote issurprisingly effective and with only simple antennas I was easily getting 20-30m range from it.By the way the place to find out anything about the 6502 and 6502 based projects is here at6502.org.

Figure 10. The real remote and mine showing how the remote andantenna light glow. Bender is looking menacing but really he'sarmless (boom boom)!

July 1st 2007Finally some progress has been made on Benders arms. Today I used my router circle cuttingjig to make small wooden discs to be the ends of the arm and wrist as well as mounting pointsfor the shoulders. The discs are slightly smaller than the diameter of the pool noodle. The shapeof the arms is made from half inch copper water pipe. Into one end of each pipe I soldered a8mm nut. This is the shoulder end which will be attached to the body with a 8mm bolt threadedthrough from inside the chest. The pipe when then carefully bent using a vice. The pipe does endup kinked and squashed but this doesn't matter as none of that is seen.

Figure 11. Mounting nuts and pipes, copper arms bent and attached,pool noodle covering.I then made holes in the centre of two of the wooden discs and hot glued them to the copperpipe. I was then able to slide a length of noodle over the copper tube. I found that the tight bendin the pipe meant I needed to cut V shaped notches into the noodle to get it to bend nicely aroundthe pipe. As the arms will be covered in fibreglass these notches don't matter at all. I coveredover them with strips of masking tape. Once the noodle would fit nicely I hot glued anotherwooden disc to the wrist end of the arms. The noodle is glued on it's ends to each disc. I did atemporary test fitting of the arms and they look great! I still need to make the shoulder fittingwhich will consist of a wooden disc on the inside and the outside of the body. These will bebolted to each other with the body in between. Through the middle of them will be an 8mm bolt towhich the arms threads on. A spring should allow the arms to be rotated and positioned whereever I like. The hands will probably be attached to the end of the arms using strong magnets sothey too can be positioned as I like.

Figure 12. Arms aren't bendable but they are able to rotate intovarious Bender poses.I have added the shoulders now. These are simply more cut up polystyrene spheres. These arepainted over then covered in fibreglass to form a hard shell. Inside the body I have glued awooden disc through which goes an 8mm bolt into the end of the arms. There are severalwashers and a spring (taken from an old fridge compressor) to provide tension on the arms.They can rotate but will stay in whatever position they are put in due to the spring tension.

Figure 13. Details of the shoulders and the internal arm fixing boltand tension spring.I also did some work in mounting the brain into a unit more suitable for head based installation.The circuit boards are mounted to a red plastic base board. This board has switches andsockets on it. The switches are the main power switch and a push button reset switch. Thereare sockets for an external power supply as well as a RCA socket to plug the speaker into. Onthe rear of the mounting board is a four D cell battery holder. The brain can be run on either theplug in power supply or off the battery making it completely portable. The brain and speaker willbe mounted (somehow) into the head.

Figure 14. The completed brain with battery supply.August 5th 2007No pictures just now but I have started fibreglassing Benders arms and shoulders. I found thatpainting the polystryene isn't enough. The resin got into the paint and slowly ate the shoulderformers away as the resin hardened. I was hoping the resin would go off before the polystyreneformer disappeared and it seems I did manage to get away with it. One shoulder is a little lumpybut nothing some sanding and bogging won't fix. I have also done several layers on one arm as Ican only work on one at a time. It will need a lot of sanding and smoothing off as it is trickyfibreglassing over such a curved surface but I am sure it will work out in the end. Unfortunately Ihave run out of woven cloth which means next weekend another trip to the fibreglass place. Onegood thing I discovered thought is pool noodle foam is resin poof meaning I didn't have to doanything fancy covering that foam before laying on the fibreglass.I am also working on drawing up the circuit diagram of the brain and associated circuitry.August 11th 2007I did an early morning trip out to New Zealand Fibreglass to get more cloth this morning. Ifanyone is doing a fibreglass project like this I can recommend them. There is another placecloser to me, Nuplex Industries, but they were completely hopeless. I called them and the guyon the phone was utterly useless. So I decided to pop down there to see if I could get betterservice in person. Nope. I think it was the same utterly useless guy. After ignoring me for 5minutes he finally came to see what I wanted. I told him what I was doing and asked what hethought would be the best resin to use. He didn't know. I asked what the best cloth to use wouldbe and he recommended some rather thick chopped strand mat. I suspect because that's allthey seemed to have. I asked how much resin do you need for a certain amount of cloth. Hedidn't know. I asked him how much it would cost and he couldn't tell me that either. I think he'd

been sniffing too many fumes from the resin spill that seemed to have been left in the middle ofthe floor. So yes, definitely leave them well alone and go to NZ Fibreglass instead is my advice.When I got home I did some more on one of the arms and will start the other soon. I need to holdeach arm in the vice to be able to lay the glass onto them so I can only work on one at a time. Ialso drew up part of the circuit diagram for the brain. So far I have only done the CPU board but Ishall hopefully finish the audio board soon. This circuit should be pretty close to the finishedproduct but I make no guarantee it will work as drawn. There may be errors in it. I had to do a bitof a brain-ectomy and partially dismantle it to be able to trace out parts of the circuit I hadn'tproperly documented when I prototyped it.

Figure 15. Click on the image to bring up the diagrams and sourcecode.The audio part of the circuit is now included above

Figure 16. Making the arms shorter.People are probably wondering about the lack of updates. It's not due to a lack of progress,more due to the fact the work being done is tedious and boring. I have been continually coatingBender in resin and sanding Q cells (small glass beads mixed in with the resin to bulk it up andmake it easy to sand smooth) and then sanding him back to get a nice smooth surface to him. Inthe pictures above the head, body and legs are all covered in one of many layers of grey primer.The right arm is whiter than the left because it has a heavy coating of resin and Q cells stillwaiting to be sanded smooth. For the sanding I use an electric random orbit sander. You need tomake sure you wear a good dust mask so you don't inhale any of the sanding dust. It is best tosand outdoors too due to the amount of dust created. Unfortunately that left me at the mercy ofthe weather meaning I could only work on Bender on fine days.I also added the hands which are made from two plastic cups cut to size. They were hot glued tothe ends of the arms and then a circle of wood was hot glued into the open end to close them off.The whole hand was then covered in several layers of fibreglass and faired smoothly into thearms. About this time I decided I had messed up and made the arms a bit too long. So I took ahacksaw and chopped a 100mm section from the middle of each arm. The image above give agood cross sectional view of one of the arms. To rejoin the two halves I used more hot melt glue(wonderful stuff!) and masking tape wrapped around the outside. Then several layers offibreglass over that. Once sanded smooth the join is strong and invisible.

Figure 17. Final painting.Once everything was sanded smooth and covered in sanding primer (and sanded yet again) Iapplied the top coats. I used a custom mix of grey paint for the overall colour. The paint I amusing is Dulon car paint. I had to take a Futurama comic book to the paint shop to ge the colourmatched accurately. That turned out to be difficult as in the comic they use different shades ofgrey all the time. I picked something representative and gave Bender a good number of coats ofit using a spray gun and air compressor. One problem with using car paint is it is typicallydesigned to be glossy straight out of the gun. Bender came out too shiny! You can see the glossin the first picture. Now despite Bender always commenting on his shiny metal ass it actuallyisn't that shiny. In fact Fry mentions this in the pilot episode. To get around this I had to wait untilthe paint was dry then go over the whole thing with a fine flexible sanding block. This took theshine off the paint and gave Bender a more accurate matt look. In the last picture you can seethe arms are still very glossy while the body and head are now dull.Before painting the arms I added the fingers which are simply pieces of wooden dowel hot gluedinto place. To make sure they don't break off I drilled them down the centre and added a smallerdowel that fits into holes in the wooden end plate of the hands. Unfortunately I made a mistakepainting the arms. The arms and legs (and antenna) are actually a darker shade of grey from therest of the body. I had a hard time finding a spray can that matched the right colour. I triedseveral but didn't get the shade I wanted. I didn't want to have to get a whole litre of custom paint

made up for those small areas that needed painting. In the end I discovered that the zinc richprimer I use when welding was actually about the right shade. I sprayed that on the legs and thatworked great. When I tried it on the arms however it reacted with one of the test coats of paint Ihad tried (just on the arms). I had to sand all the paint off the arms again and then re-spray them.The eyes and mouth, which most people are surprised to find are yellow not white, were sprayedusing spray can paint. I had to mask of the rest of the head with tape and paper then sprayed anumber of coats to build up a nice depth. I left the eyes and mouth glossy.You will probably notice here that the shoulder section still looks very rough. This part I amleaving till last as I want to build it up so the joint between the body and bottom of the shouldersis nice and accurate. At the moment the shoulders are slightly smaller than the top of the bodyleaving a small step in the join. The head is just sitting on top of the shoulders and it is easilylifted off but it is located in position by two wooden dowels. These protrude up from the shouldersinto small holes in the bottom of the head.

Figure 18. Mounting the brain inside the head.One thing I have been wondering about for some time was the best way to mount the braininside the head. The solution in the end was quite simple. I simply bent the aluminium bracket Iused as a stand to sit the brain on into a square J shape. I then bent a piece of brazing rod into asimple hanging bracket that is screwed up into the top of the head. The brain simply hooks overthat rod and hangs freely inside the head. The switches and controls are at the base of thehanging brain so you can reach them from inside Benders body. I am still not sure the best placeto put the speaker for the voice. Inside the head the sound is somewhat muffled so in practicethe speaker may need to sit inside the body on top of the beer keg. I will wait until the door isfinished then figure out the best placement for the speaker then.

Figure 19. The completed head.Once the eyes and mouth were painted and the brain mounted I finished up the rest of the head.Around the eyes I painted matt black paint using a small brush and a small touch up jar of paint.The eyes and mouth lines are made using black car insulation wiring tape. This is different tonormal insulation tape in that it is very low tack (since in a car normal insulation tape will turn intoa gooey mess over time). The tape can easily be peeled off if I want to change the shape of hismouth later on. For now I went with the square look. The ball on the top of his antenna lights up

red when a button on the remote is pressed to make him speak.November 25th 2007Bender is finally complete! I finally finished off his shoulders and his door which is made fromreal sheet steel. To make the door I first marked out the rough dimension on a sheet of steelensuring that the piece of steel was bigger than the opening in the body. I am using thin carpanel steel which is only about 0.8mm thick so easy to work. I then roughly made the curve inthe steel using my welders gas bottle as a former. It is easy to carefully bend the steel aroundthe tank starting at one edge and working around to give an nice even curve rather. Once thebulk of the curvature was formed in the steel small adjustments were made simply bending it byhand.After the curvature was such that it matched the profile of the body I temporarily taped it in placeover the opening then I was able to scribe a line from inside that matched the hole for the door.When cutting the steel I found the easiest way to get a nice smooth line was to lay a strip ofmasking tape along the steel and use the edge of that as a line to cut against using Gilbow metalsnips.

Figure 19. Making and fitting the steel door.To hinge the door I used three small metal hinges. I ground the end off and removed the pins

which I replaced with short lengths of brass welding rod bent so I can easily remove the dooragain if I need to. One half of each hinge was simply MIG welded to the door. The other side ofeach hinge was screwed into Benders wooden frame. I did have to do some minor surgery withthe router to get a flat surface on the framing dowels to screw each hinge down to. The door isheld in place with a simple magnet on the right hand edge. The door knob is simply a small discof steel slightly curved to match the profile of the door. It has a smaller curved washer under it tomake it stand off the door panel by a mm or two. These were then welded to the door.After finishing the door I also finished the shoulders which was a simple matter of building up thesurface with fibreglass and body filler then sanding it smooth so it matched the bottom of thehead and the top of the body. Benders head can be turned by turning the head and shoulderstogether.So finally Bender is complete!

Figure 20. Bender complete!Here is Bender still in the garage where he was born, errr, made. Soon he will be venturing out

though. You can see him here with his door painted to match the body and you can see how thebeer brewing keg fits inside him. The beer tap rotates so the door can be closed over it. Don'tmention the placement of the tap. It makes Bender angry as you can see in the lower left.His scowl I made from a left over polystyrene sphere the same size as the one used for hiseyes. I wrapped it in tin foil then added several layers of fibreglass. Once that had dried I sandedit all smooth then using a hacksaw I cut out two sections similar to the sections you get whenyou cut an orange. I epoxied these to a flat plastic base and painted the whole thing with thesame matt black paint as used around his eyes. The scowl can then be clipped into place asneeded over the eyes and held in place with a small blob of Bluetac.The cigar was made from an old whiteboard marker pen I cut up and painted. The burning end ismade from black felt with a disc of red felt in the end. Inside the marker I have a small penlighttorch which when switched on causes the red felt to glow. The cigar is held in place with astrong magnet in the base with another inside the head attracting it into position.Finally a picture of Bender playing one of his favourite computer games!Still to come is the actual brewing of beer.

Figure 21. Bender doing beer research, beer brewing kit andfermenter.Finally the time has come for Beer Brewing Bender to fulfill his destiny. Beer making time!

The beer we are making is made from a kit bought from the local brewing supply place(Brewcraft in Mt Edenhttp://www.ebrewcraft.co.nz across the road from Galbraiths pubhttp://www.alehouse.co.nz). The different things you need are shown above. First Bender and Ihad to go do some research at my favourite local pub, Galbraiths. He is looking pissed offbecause 1, I didn't get him a drink before taking the picture and 2, he needed phone books tostand on to reach the bar. His extending legs were broken that day.In the middle picture above you can see most of the things you need to make beer.Sugar. Usually you'd use dextrose but in this case I am using something called an enhancer.This is a mixture of sugar, malt and hops. This is supposed to give the beer a fuller flavour thanjust sugar alone.Tin of beer concentrate and yeast. These come together as a package.Sterilising power sachets. You mix these with water and use them to clean the fermenter,bottles and all the equipment you use.Hydrometer and measuring cylinder. This is used to measure the specific gravity of the beer.Mixing spoon.Sugar tablets. Used when bottling to add the last bit of sugar to the beer before conditioning.Fermenter. With airlock and temperature strip.One of the most important things is everything has to be very clean. Wash everything thencarefully sterilise everything that will come in contact with the brewing beer.When everything is sterilised we can start mixing the ingredients.

Figure 22. Mixing up the beer.First you need to sit the can of concentrate in hot water for 10 minutes or so to make it morerunny. Even then it is the consistency of honey. It also has the taste of beer flavored honey. Infact for a second I was seriously considering buying some just to spread on my toast in themornings. Woo! Beer for breakfast!Once the can has heated up you transfer it into the fermenter. Next you mix up thesugar/enhancer with 2L of hot water. Sugar will dissolve easily but the enhancer you need to mixin carefully to avoid it forming lumps. I mix it a bit at a time in the tin the concentrate came in thentransfer that to the fermenter. Once the sugar/enhancer is thoroughly mixed in with the

concentrate you fill up the fermenter to just under 23L with water. You must make sure thetemperature is between 18-28C to avoid killing the yeast which is added next. The yeast issimply sprinkled into the top of the barrel then mixed in.I mixed the concentrate and sugar with the fermenter on my kitchen bench. Then I placed thefermenter inside Bender's body before adding the rest of the water.

Figure 23. Closing up the fermenter and taking the original SG reading.Once all the water and yeast is added you put the lid onto the fermenter. This has a rubber sealto give a good airtight fit. In the top of the fermenter is a hole to which is added an airlock. Theairlock is a bent plastic tube you half fill with water. As the beer ferments it gives off bubbles ofCO2 gas. This gas bubbles out of the airlock but no air can get in.In the second picture I am taking a sample of the mixture before any fermentation has begun. Ifyou take a specific gravity (SG) reading at the start and another at the end of fermentation youcan calculate the alcohol content of your beer. I did feel a little dodgy taking that sample givenwhere the tap is. Bender didn't seem to mind. With a sample in the measuring cylinder you floatthe hydrometer in it. This floats at different levels depending on how much sugar there is in themixture. As the yeast converts the sugars into alcohol the SG changes. You can tell when thefermentation is over when the SG value remains constant. As the beer is fermenting you takeperiodic readings to follow it's progress.The initial reading I got was a SG of 1.034.

Figure 24. Bender with brewer inside.I will add further updates as the brewing continues.December 22nd 2007Bender isn't happy. For some reason the beer isn't bubbling. This could be due to several things.1, the mixture was too hot before adding the yeast and it died in the hot conditions. Or 2, theairtight fermenter isn't actually airtight. I took a SG reading though and it has dropped. From1.034 to 1.014 so it seems something is happening. The instructions say you bottle when the

reading has been stable at around 1.006 for a few days. I shall keep going and see if it doesindeed continue to drop. I also checked the seal around the lid of the fermenter and found thatwhere the two sides of the moulded plastic container join there was a ridge of plastic. This mightbe preventing the 0-ring in the lid from sealing properly so I carefully cut this away with a sharpknife. Hopefully now the container will pressurise correctly.

Figure 25. Lack of bubbles make Bender an angry Bender.More updates to follow.

December 30th 2007Bender's bubbly personality finally came through! After making sure the fermentor was sealingcorrectly the beer did start bubbling through the airlock. This continued for quite a few days buthas now slowed considerably. A SG reading shows the beer is not quite ready for bottling bygiving a reading of 1.008. Bottling has to be done once the beer goes below 1.006 according tothe instructions otherwise there is a chance the bottles will over pressurise when the finalamount of sugar is added and they could explode! I will give it another day or two then takeanother reading. If it has stopped changing I will bottle it despite the reading being a touch high.January 2nd 2008The day finally arrived. Bottling day! The SG readings finally settled on 1.006 (just) and stabilisedso today I bottled the beer.The procedure is something as follows:1. Clean and sterilise the bottles. I use 750mL plastic PET bottles. A batch of beer will fill 30 ofthem.2. To each bottle add sugar. I use sugar drops and add two per bottle (see below). The additionalsugar is to allow for extra fermentation in the bottle. This is what causes the beer to havebubbles.

Figure 26. Sugar drops to carbonate the beer in the bottles.3. Remove the airlock from the top of the fermenter to allow the beer to flow freely.4. Warm your hands (Not normally necessary but Bender insisted on this step before letting menear his tap).5. Slowly, with each bottle tilted to avoid frothing, fill each bottle from the tap.6. Tightly cap each bottle.Once all the bottles are full and the caps tightened we are almost done. Now we must wait. Thebottles must be stored somewhere warm for 5 days. This is to allow the secondary fermentationto take place. This pressurises each bottle with CO2 gas. After the 5 days you move the beersomewhere cooler to allow it to mature. You can supposedly start drinking the beer after a week

but generally the longer you leave it the better. The plastic bottles however probably limit it to ayear or so before they start leaking.

Figure 25. Bender looking pleased with himself for a job well done.By the way I did have a little taste of the beer before I bottled it. It wasn't totally unpleasant. Ittastes very green but it had a fair amount of body. Yeasty with maybe just a hint of Mom'sOld-Fashioned Robot Oil!January 7th 2008

The bottles have now all pressurised in the warm and are ready to be put away in the cool untilready to be tasted! As one final finishing touch each bottle was given it's own Bendrbrau label.Many thanks to my friend Jen who did the graphics for the labels for me.I did have a little problem printing them out however as my crappy HP printed decided to die. I'fixed' it however.With my oxy-acetylene welding/cutting torch(http://www.youtube.com/watch?v=Z5V8sKjMUF0)!And I tell you, that felt great!

Figure 26. BENDRBRAU - Let's get drunk!Now all there is left to do is drink it once it has matured!

This is the circuit for the CPU part of the brain. Forthe sake of clarity I have not shown the decouplingcapacitors across each IC or all the unused logic gates.Any unused logic needs to have it's inputs tied eitherhigh or low to avoid odd things happening in thecircuit. Floating inputs are bad! I have also left offthe details of the power supply. I used a LM2940 LowDropout regulator to give me a stable 5 volt supply. Theinput can be from a wallplug pack or from 4 D cells.Remember I am not an electronic engineer so this circuitmay not be optimal. It does work though!It is based rather heavily on the original 1541 diskdrive circuit. I simply took off the bits I didn't needsuch as the second VIA, second ROM and all the I/Ocircuitry and added my own clock and manual resetcircuit. I also used a 27C64 EPROM. The original driveuses two 2364 devices which are impossible to get now.One thing people may wonder about is the flip-flopbetween the CPU and clock generator on the right handside of the diagram. That is a clock divider circuitwhich I had to use since the CPU I have is a 1Mhz deviceand all I could get locally were 2Mhz clock crystals!

Below is the circuit for the audio part of the brain.

The circuit is a little convoluted I guess and there aredefinitely much easier ways to do this but I was makinguse of the parts I had easily available. Basically atimer drives a binary counter which then addresses bitsout of whichever ROM chip is selected by the CPU at thetime (I could have up to ten but I only used three). Thetop four bits of the counter (A14 - A17) are presettableby the CPU and these are set just before a play starts.Setting the address also resets the two lower bitcounters back to zero. Using these top four bits meansthe memory is effectively split into pages with eachpage start being addressable using these bits. Thesamples are stored starting on a page boundary so theCPU can start playing at the beginning of each sample.The samples may be longer than one page in length. Todetect when to stop playing I encoded at the end of eachsample the maximum 8 bit value, 255, and I detect whenall the output bits go high with an 8 input NAND logicgate. This causes and interrupt signal to the VIA whichthen interrupts the processor which knows it should stopplaying. The audio is converted from digital to analoguewith a simple R-2R ladder. This provides good enoughaudio quality for the simple speech I am playing. I usea LM386 on the audio board as a small amplifier. Theclock is a simple 555 timer based circuit which runs allthe time. The clock signal is gated to the rest of thecircuit by the CPU. When a play finishes the clocksignal is switched off stopping the play and we simplywait for another play trigger input.

Below is the 6502 assembly language. Again I am not a

professional software engineer. Actually, I am, but notin 6502 assembly language. This was my test code andfirst real 6502 assembly language program so again itmight not be efficient or pretty but it does the job. Idid that thing all software engineers will know about. Isaid I'll do a prototype then rewrite it once I know howit works. Of course we'll never ship with that prototypecode.....rom_start = $E000 ; Start of ROM memoryreset = $FFFC ; Reset vectorinterrupt = $FFFE ; Interrupt vectorvia = $1800via_b = via + $0 ; VIA port bvia_a = via + $1 ; VIA port avia_bdir = via + $2 ; VIA port b direction 1 = outputvia_adir = via + $3 ; VIA port a direction 1 = outputvia_pcr = via + $C ; VIA peripheral control registervia_ier = via + $E ; VIA interrupt enable register

chipsam = $07FE ; Store the chip and sample to playplaying = $07FF ; Are we currently playing flag

.ORG rom_start

;InitilisationLDA #$FE ; Load ACC with b11111110STA via_bdir ; Set VIA port b all output except b0 inputLDA #$FF ; Load ACC with b11111111STA via_adir ; Set VIA port a all output

LDA #$CC ; Load ACC with b11001100 - PCRSTA via_pcr ; Set VIA PCR for CA2, CB2 held low, CA1, CB1 high->low transition

LDA #$82 ; Load ACC with b10000010 - IERSTA via_ier ; Set VIA IER for CA1 active

LDA #$00 ; Clear the playing flagSTA playing

CLI ; Enable interrupts

; Simply loop around storing each samples location in memory.; Then poll to see if we were triggered to start playing.

loop

c1s1 LDA #$00 ; Data b0000 0000 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 1, address 0000JSR poll





c1s6 LDA #$0A ; Data b0000 1010 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 1, address 1010JSR poll

c1s7 LDA #$0C ; Data b0000 1100 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 1, address 1100JSR poll





c2s5 LDA #$1D ; Data b0001 1101 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 2, address 1101JSR poll




c3s4 LDA #$2B ; Data b0010 1011 - CHIP SELECT/ADDRESS

STA chipsam ; Store data - chip 3, address 1011JSR poll

c3s5 LDA #$2D ; Data b0010 1101 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 3, address 1101JSR poll

c3s6 LDA #$2E ; Data b0010 1110 - CHIP SELECT/ADDRESSSTA chipsam ; Store data - chip 3, address 1110JSR poll

JMP loop

; Polling subroutine. In here we check if the button is pressed (portb 0 == 0); and if so start playing the currently stored sample.

pollLDA playing ; Check if we are playingAND #$01 ; 1 == playingBNE return ; We are playing so just keep looping

LDA via_b ; Not playing so check VIA port bAND #$01 ; Check portb 0 == 1 (button NOT pushed)BEQ play ; No button is down, start playingJMP return ; Button NOT pressed so return

playLDA chipsam ; Retrieve the chip and sample dataSTA via_a ; Push it to the VIA port a

LDA #$40 ; Data b0100 0000 - Reset and loadSTA via_b ; Load data on port bLDA #$80 ; Data b1000 0000 - Start playingSTA via_b ; Load data on port b

LDA #$01 ; Set the playing flagSTA playing

LDA #$82 ; Load ACC with b10000010 - IERSTA via_ier ; Set VIA IER for CA1 interrupt active

returnRTS ; Return

; Interrupt service routine. this is triggered when the 6522 VIA interrupts; at the end of a sample. We store the ACC, clear the interrupt. We reset the; audio board by clearing port a, resetting the counters and stopping the play.; Then reset the playing flag, restore the ACC and continue.

isrPHA ; Store the accumulator

LDA #$02 ; Load ACC with b00000000 - IER

STA via_ier ; Clear VIA IER for CA1

LDA #$00 ; Reset port back to zeroSTA via_a ; Push it to the VIA port aLDA #$40 ; Data b0100 0000 - Reset and loadSTA via_b ; Load data on port bLDA #$00 ; Data b0000 0000 - Stop playingSTA via_b ; Load data on port b

LDA #$00 ; Clear the playing flagSTA playing

PLA ; Retrieve the accumulatorRTI ; Return back to looping through samples

.ORG reset ; Reset vector

.WORD rom_start

.ORG interrupt ; Interrupt vector

.WORD isr

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