Datalogger STRATO3

Record your high altitude flight

Introduction

The Datalogger STRATO3 is a user-friendly device to record data in high-altitude flights. It

records GPS coordinates, altitude, internal temperature, external temperature, pressure and

humidity. Our online tool creates all the graphs and the flight track can be displayed as a 3D-

Google-Earth curve.

Data Evaluation:

www.stratoflights.com/evaluation

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Features

Records GPS coordinates, altitude, pressure, internal and external temperature, humidity in real-time. Unlocked GPS module: Records data up to an altitude of 50,000m (164,000 ft). Most modules are limited to 18,000m. Records data on micro SD flash cards Online-Tool to create graphs from the measured data Online-Tool to create a 3D-Google-Earth flight track Easy to use, no programming necessary Credit card sized, lightweight design (50g) Power Supply: 9V Battery

Quick Start Install the 9V Battery, insert the microSD card and turn on the power switch (S1). The datalogger starts to locate its position and records automatically. By pressing the button (S2) you can switch through the menus to show different live measurements. To stop recording turn off the power switch.

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Hardware The STRATO3 hardware module (fig. 1) includes an onboard digital display. Switch (S1) can be used to turn on the datalogger and Button (S2) to start recording and to switch through the menus. The function of each component will be described in further chapters.

Figure 1. The Datalogger Hardware

Figure 2: External Sensors (Temperature, Pressure, Humidity)

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Getting started Power supply

The datalogger can be run by a 9V Battery. Switch (S1) can be used to turn on the datalogger. You can find an appropriate 9V Battery in our online shop at www.stratoflights.com/shop Mounting the datalogger

The datalogger performs best if you keep the temperature above 0°C. You can protect the datalogger within your polystyrene probe. The external sensorboard can be positioned outside the probe. It is important that the module does not touch any metal surfaces as this can short the metal contacts on the module. You can bag the datalogger in the pink antistatic packaging to protect it from short-circuits and shocks. Make sure that the module does not contact water or other liquids. The datalogger receives the strongest signal if the antenna is facing upwards (display shows towards the sky). The external sensors should be protected from splash water.

Recording

To save the data you can use a common microSD-card with a capacity of up to 32GB. It is recommended to test the microSD card before you use it in a high altitude project. You do not want to fly into the stratosphere to notice afterwards that the microSD card didn't work. The datalogger stores the measurements every 2 seconds. Each dataset needs about 128 Bytes. A 2GB microSD card is capable of recording about 360 days in a row - this should be more than enough for most of your projects.

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Operation

During operation, the module continuously displays measured data. The datalogger starts recording immediately and automatically. This reduces the risk of a flight without any data. To stop recording turn off the power switch (S1). The data will be saved as (.log). To interpret the data we developed an online tool. You can simply upload your files and the tool will create different graphs about all your measurements. Please find more information on that in the further chapters. Each time recording is started, a new data set is recorded. When recording is stopped, the data set is closed. Data files are named starting with “F_” followed by a number and a .log extension. At powerup, the Datalogger will find the next available file name and continually sequentially from there for each new data set. As soon as the GPS signal is valid it will show its position on the Display. Note: The GPS module has different modes to run at, depending on its application. We use the modules for high altitude projects so that we configured it in the 'airborne mode' which enables a continuous recording up to an altitude of 50,000m. This mode is slightly imprecise in stationary applications. If you are wondering why the data recordings on the ground have small variations this can be attributed to the airborne mode. As soon as the datalogger rises he is in its ideal environment and the GPS signal can be used perfectly.

LED-Status LED 1 (red): Generally the LED is out. When it glows permanent this means that the datalogger reports an error. The most common causes are:

microSD-card defect or not readable

GPS error (no signal)

sensor connected improperly LED 2 (green): When you turn on the datalogger starts recording automatically and the green LED blinks. Note: As soon as the datalogger receives a valid GPS signal the datalogger starts recording the measurements automatically.

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The Menus By pressing the button (S2) you can switch through the menus of the datalogger. These are:

Menu Display Description

1. Status Up: ... Batt: UTC: Logging to: GPS:

Uptime in hours:minutes:seconds Battery Voltage in volts Coordinated Universal Time; Date Filename from the current logfile GPS-Data-Status

"Data valid" -> GPS Data valid

"Data not valid" -> wait for signal

2. Sensors

Board Temp: Extern Temp: Extern Hum: Extern Press:

Temperature of internal board sensor in [°C] Temperature of external board sensor in [°C] Humidity of external board sensor in [%] Pressure of external board sensor in [hPa]

3. GPS Data RMC: SiU: Lat: Long: SoG: CoG: Alt:

GPS Status: "Data valid" -> GPS Signal valid Satellites in Use Latitude in degree and decimal minutes Longitude in degree and decimal minutes Speed over Ground in [km/h] Course over Ground in [Grad] GPS Altitude NN in [m]

Note: If a sensor is connected improperly the menu line says 'error'. In this case you can check the connections according to fig. 1.

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Data Evaluation The datasets will be stored as a .log file and can be opened with different programs. Copy the Logfile from the microSD card onto your computer. Important: Before you open the file we recommend to create a backup from the file on a different memory location. If the file will be overwritten accidentally with a program like Excel the data might not work anymore with our online-tools. That's why we recommend to work only with copies from the unopened original files. The data which will be recorded are in detail:

Data Meaning

Up-Time Runtime

UTC Coordinated Universal Time

Date Date

RMC Valid GPS Data valid

Sats in use Number of satellites in use

Latitude Latitude

Longitude Longitude

Speed over Ground [knots] Speed over Ground

Speed over Ground [km/h] Speed over Ground

Course over Ground Course over Ground

Altitude NN [m] Altitude NN

Board: Temp [C] Board Tempterature

Extern: Temp [C] External Temperature

Extern: Hum [perc] External Humidity

Extern: Press [hPa] External Air Pressure

Batt Voltage [V] Battery Voltage

Logger Status Logger Status für Debugging

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Online-Tool to create graphs To visualize your measurements and flight paths we developed an easy-to-use online tool: www.stratoflights.com/evaluation Procedure: Press the button and then choose your logfile. The data will be uploaded and within seconds our tool creates a summary about the extreme measurements.

Create Graphs: Choose the datasets for the x-axis and the y-axis.

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The graphs will be created automatically including. In the measurement range below you can tri the front and end so that just the interesting data from the flight will be displayed. The graphs can be downloaded as PNGs afterwards.

Create Flight-Paths in Google Earth To visualize the data in Google Earth the logfiles have to be modified. Open the file with the Editor. Now you can see the datasets. It is important that you delete the first row (marked as blue) and save the file with a different name

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The new file is ready to use now and can be visualized with the following tool: http://www.gpsvisualizer.com/ Procedure: Click the button and upload the new file. Now you can choose an output format. An easy option is the 'PNG map' which will be created as a 2D-flight-path from the latitude and longitude.

3D-Flight-Path If you want to create a 3D-flight-path for Google Earth you have to prepare your logfile (as described in the section before). The tool to create the Google Earth File can be found on the link on the right side which says 'Google Earth KML'.:

Procedure: Click the button and upload your prepared logfile. Now you can type in a name for the file.

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Choose the Altitude mode as Absolute (for flights). In this case the tool interpres the data also in altitude which gives you a beautiful 3D-fligh-path. For an application on the ground you can choose an alternative mode. Now you can click 'Create KML file'. The google earth file can be downloaded and opened.

Display in Google Earth: A double click on the file opens the flight path (if Google Earth is installed). Otherwise you can find the newest version under: https://www.google.de/intl/de/earth/ Now you can turn around the map and scroll in and out to view the flight path from any perspective.

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Create interactive 3D-Flight-Tracks in Doarama To create your personal 3D-fligh-track you can upload your flight data to Doarama. Therefore you have to convert the logfile from the datalogger into a GPX-file. You can do this here: www.stratoflights.com/evaluation The new file can be uploaded to Doarama: www.doarama.com Click on Create your own track. Then you can login with your Google or Facebook Account. The tool is free. In the second step you can upload your GPX file. Now you can choose the ‘activity type’ to ‘Fly – Balloon’.

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Finally you get an interactive 3D-Flight-Track. Now you can play the video and display interesting data like:

Current Altitude

Speed

Distance from starting point

Climb Rate

Time

Flight Duration With the help of this tool you can visualize your flight in an awesome way. It is interesting to see how the balloon changes its speed and direction in different altitudes.

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UART-Interface Hardware:

To use the measurements for further developments in your own projects the datalogger provides a UART port. The connectors are:

3,3 V: Supply Voltage (optional)

GND: Ground

RDX: Receive Port

TDX: Transmit Port

All signal levels of the UART are 3,3 Volts.

Software:

Configuration / Specification:

Baudrate: 57600 Baud

Framing: 8N1

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Protocol: Data string

As soon as the Stratoflights-Logo on the display goes out the data string is ready to be received. This is ca. 2-3 seconds after switch on.

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The following steps are necessary to get the current data string:

1. Send of T or 0x54 2. Send an i or 0x69 3. Polling until the datalogger confirms with 0x01. Old requests can be handled until

confirmation. 4. Directly after confirmation the datalogger sends the current data string. The string ends

with a Carriage-Return, followed by a Newline: \r\n bzw 0x0D, 0x0A.

For testing you can send the letters T+i via a serial concole (e.g. with Putty) via a keyboard entry. Then the current data string will be displayed in the console window.

The received data string hast he following structure:

$;Up-Time;UTC;Date;RMC Valid;Sats in use;Latitude;Longitude;Speed over Ground [knots];Speed over Ground [km/h];Course over Ground;\Altitude NN [m];Board: Temp [C];Extern: Temp [C];Extern: Hum [perc];Extern: Press [hPa];Batt Voltage [V];Logger Status\r\n

It can look like this example:

$;00:05:13;19:36:26;13.09.2016;Y;04;40 40.68437 N;005 30.70415 E;0.432;0.800;;91.2;11.625;12.625;37.56;1009.809;8.6;66679

With:

Character Meaning

$ Control character: Beginning of the string

; Control character: Separator

00:05:13 Current runtime for data recording

19:36:26 Time of the data set (UTC). If the time is not available: NA

13.09.2016 Date of the data set

Y GPS-data set is valid. N: GPS-data set not valid

04 Number of the satellites in usw. NA is GPS signal is not valid.

40 40.68437 N Latitude. NA if GPS data is not valid.

005 30.70415 E Longitude. NA if GPS data is not valid.

1.358 Speed over Ground in knots. NA if GPS data is not valid.

2.5 Speed over Ground in km/h. NA if GPS data is not valid.

260.3 Course over Ground. NA if GPS data is not valid.

91.2 Altitude NN. NA if GPS data is not valid.

11.625 Board-Temperature in degree Celsius. Err if temperature is not valid.

12.625 External-Temperature in degree Celsius. Err if temperature is not valid.

37.56 External relative humidity in percent. Err if humidity is not valid.

1009.809 Air pressure in hectopascal. Err if pressure is not valid.

8.6 Battery voltage in Volts.

66679 Logger Status

\r\n Control character: End of data string.

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Specifications Parameter Value, Unit

Input Voltage 4,5 - 9 V

Temperature Range 0 bis + 85 °C

Maximum Altitude 50.000 m

Pressure Range 10 bis 1200 mbar

Humidity 0 - 100 %

Recording Rate 0,5 Hz

Measured Temperature Range ext. - 55 to + 85 °C

Measured Temperature Range int. -40 to +85 °C

Dimensions 85 x 54 x 10 mm

Weight (without Battery) 50 g

Weight (with Battery) 94 g

Battery Life 24 hours

Note: These Specifications have been taken from the manufacturers data sheets and may not

have been tested to the full extent of the specified ranges.

Have a great flight!

Everybody needs an adventure!

www.stratoflights.com/tutorial