Greetings! I'm looking for someone who has AFSK experience and an interest in sharing some of that knowledge as I build a project this year that will evolve over the summer into part of a hands-on course for advanced middle and high school students. This project involves ham radios - I am a licensed ham operator.
I know there will be a temptation to suggest other ways of doing this project - we're all like that sometimes. Please keep in mind I have solid reasons for approaching the project as described below. I have about 30 years experience tinkering with technology such as the Arduino, but not a formal computer science degree. I'm someone who codes to get stuff done, not for the joy of it. (Therefore holes in what I know. But always happy to do my homework if folks are willing to suffer through a couple "everyone should already know this" questions.)
I need some coding and electronics assistance with a project to turn an Arduino into a Terminal Node Controller (TNC) which is a modem for communicating over a 2m ham radio.
I'll know this project is successful when...
I can send and receive serial data from another Arduino or device, which this Arduino will process using AFSK and connect to a ham radio - a TX cable to the Mic port and an RX cable to the Speaker port. Once this is tested, the next step is to ensure the data processing (encoding/decoding) is done as APRS packets.
I need some help with...
- The hardware (I've played with the Markqvist board but am not sure I have it done correctly and not sure what other configurations are out there or how they compare.)
- The software (looking for libraries and sample code - I can make round pegs fit in square holes if I at least have a place to start.)
- I'm not using an on-board "radio" - such as the RadioMetrix HX1. It needs to be able to plug into an external 2m ham radio. (Anyone who has a favorite HX1 project and wants to transcribe it into an external radio configuration, I'm all ears - this is just a step beyond what I feel I can do/understand.)
- I'm not using a pre-made TNC. There are some great ones out there, but I want students to have a "made from scratch" experience.
- I want to focus on Arduino technology. True, it might be overkill for some of this, but students are familiar with the Arduino Uno from other projects and I want a comfortable transition to this project. So I'll probably take a solution that uses three Arduino Megas over something with a simple PIC and two components.
- I have access to a "fab lab" and can therefore mill custom circuit boards, do surface mount soldering, etc.. Eagle files gratefully accepted or even just good schematics.
- There are some great firmware solutions out there - such as Unsigned.io - where folks are encouraged to load the monolithic firmware onto the Arduino. I feel it's important for students to have the experience of setting up a library and uploading individual sketches, even if they aren't writing the code themselves.
- Purchased daughterboards are ok, especially getting something working. But I want a solution where students can put a bunch of basic components in a breadboard and make this work, so at some point the daughterboard would be broken down into components before using it with students.
Please let me know if I missed anything or if there are additional questions.
-- Markus K1FIG