Building an extremely small ARPS Tracker
1 Project goal
This project has the goal to assemble a lowest possibly imaginable power saving and absolute supercompact highly packed APRS tracking transmitter. At last, I want to be able to visualize my position...!
At last, I got all my ingredients collected:
- EM-406A, a 20 Channel SiRF III GPS Receiver from USGlobalSat with Antenna
- Open Tracker SMT
- Radiometrix HX1-144.800-3 300 mW transmitter
- Comet SMA-501 0dBi 1/4 wave miniature antenna
- http://www.sparkfun.com/datasheets/GPS/EM-406A_User_Manual.PDF EM-406A User Manual
- http://www.datasheetarchive.com/pdf-datasheets/Datasheets-3/DSA-56110.pdf RadioMetrix Module Datasheet
- http://kr.ic-on-line.cn/IOL/datasheet/mc908jl16cdwe_736434.pdf Datasheet for the Microcontroller in the OpenTracker SMT
- http://www.sparkfun.com/datasheets/GPS/NMEA%20Reference%20Manual1.pdf NMEA Reference
3.3 Other data
The tracker's inner values:
* Voltage: DC 6.5 to 28V unregulated or 5V DC regulated * Current: 8 mA idle, 20 mA transmitting Max 200 mA @ 5 V available for GPS * Modes: 1200 bps AFSK (send and receive); 300 bps AFSK, PSK31 (send only) * Radio Connector: pin header * Serial Connector: pin header * Dimensions: 31mm x 18mm x 5mm * GPS interface: NMEA in/out
Pin Name Funktion 1 5VIN Geregelter 5-Volt-Eingang 2 RxD RS-232 Data in der (vom GPS oder Computer) 3 1Wire Dallas 1-Draht-Bus für externe Sensoren 4 AOUT Audio-Ausgang an Radio 5 ADC5 Analog-Eingang 6 T1CH1 Timer-Kanal 7 ADC6 Analog-Eingang 8 RST Reset (active low) 9 ADC7 Analog-Eingang 10 IRQ- Transmit-now, Profil wählen, oder Zähler 11 ADC8 Analog-Eingang 12 ADC9 Analog-Eingang 13 AIN Audio-Eingang von Radio 14 ADC4 Analog-Eingang 15 ADC3 Analog-Eingang 16 TXD RS-232 Data aus 17 rot rot LED-Ausgang 18 grün grün LED-Ausgang 19 ADC2 Analog-Eingang 20 ADC1 Analog-Eingang 21 PTT Push-to-talk-Signal an Radio 22 REGOUT Regulator-Ausgang - 5 Volt 23 GND Ground 24 REGIN Regulator-Eingang - 6,5 bis 28 Volt
- http://www.jaeger-edv.de/Shop/index.php?page=shop.getfile&file_id=40&product_id=25&option=com_virtuemart&Itemid=53 Config Tool for the OpenTracker SMT
The following picture is from ArgentData:
And here's how to use the USB / Serial adapter from the Arduino projects: http://arduino.cc/en/Guide/ArduinoMini
I am using this adapter to program the SMT chip.
4 Project plan
- Find a cabling arrangement that works on my BreadBoard, using the Arduino USB/Serial interface.
- Rearrange all the three components on minimal space
- Build a suitable case
- Program the Opentracker SMT
- Deploy and Track
- 2009-11-05 I got my GPS box up and running. Produces really nice output. Also got the Radiometrix transmitter up and running. Produces a nice signal. Now I still need to get the OpenTracker up and running.
- 2009-11-07 Well, the tracker is not so small after all, but it still all fits into my palm, and this all includes the battery. The case is now ready and I am just finalizing everything. Still need to program the uC with my callsign.
- 2009-11-11 I heard recently that there's going to be a new APRS repeater in our region (DB0SAD). At last, I can use the device as a counterpart for my APRS node, which is currently inactive: Using the ASUS WL-500gP as a APRS digi
- 2009-11-14 I see that it is necessary to connect RegOut (5V out from the voltage regulator) with the RegIn that expects 5V input. This is necessary that the CPU can run. I also see that the HX1 module and the Tracker just like that won't co-oeprate. The OT+ draws PTT to LOW, but the HX1 expects PTT ro be HIGH (same voltage as Input Power). I solve the problem with a BC337 (general purpose) PNP and a 4.7kOhm transistor. Yet, still my tracker does not want to transmit...
Still on the breadboard...
Assembly... In other projects I have made excellent experiences with U-profiles that can hold PCB boards. Also in this case I took small snippets of U profiles and soldered them into the base box so they can hold both my carrier boards for the OpenTracker and for the RadioMetrix module.
- Since I have my APRS relay station ready to go anyway, I just need the tracker to start tracking!