Philippine Amateur Radio Association Inc. (PARA / DX1PAR)
Philippine Amateur Radio Association Inc. (PARA / DX1PAR)
I have built a DIY Bluetooth APRS module for my Yaesu FT-2900R. The device is called a terminal node controller (TNC), for decoding and encoding Automatic Packet Reporting System (APRS) audio. This DIY TNC uses a smart phone and an Android app APRSdroid. The Bluetooth module uses the RX and TX pins of an Arduino Uno R3 to wirelessly exchange text data with a smart phone.
DIY Bluetooth TNC connects an FT2900R to a smart phone running APRSdroid
The Arduino connects to the input and output pins of the radio: PTT signal, audio in (mic), audio out (speaker), GND (negative), and VCC (positive). Arduino’s A0 pin reads incoming signal from the radio’s audio out (speaker), PTT line connects to a transistor which then triggers the PTT whenever Pin 3 outputs 5V during transmission. Pins 4, 5, 6, and 7 are connected to a resistor array to compose the APRS audio, which then sends signal to the radio’s line in (microphone). GND (negative) and VCC (positive) connects to the radio’s internal power supply. To view the code and the schematic diagram, head to Home-brewed TNC by VK3DAN (Daniel Phillips).
In this particular modification, I tapped directly onto the FT-2900R’s microphone and speaker port, and also the internal voltage regulator. I then housed the module in a plastic project box (do not use metal box), with a toggle switch to easily select between APRS audio from the TNC and voice audio from the hand microphone.
An added benefit of APRS-Bluetooth connectivity is that you can be away from the radio and still send and receive APRS data in your smart phone, if within range of the Bluetooth connection. It is also very convenient to send APRS replies, since typing is done via the smart phone instead of the radio’s keypad. APRS enables radio users to transmit not only text information but also location beacons, and communicate with APRS servers and I-gates for sending data packets to the Internet. With a TNC, any radio such as this FT2900R, may be used with APRS, a feature usually found in more advanced radio units.
73, DU1AU
https://nightskyinfocus.com/du1au/
Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines