Newbie at hello world status with Arduino and UV5R

Hi, I’m a newbie in the world of HAM but looking for a solution to a problem. I am seeking to transmit temperature data from my car in the case of monitoring the temperature for my service dog. I have a cellular based device I pay for but the problem is there are times I’m in area’s where there is no cellular. At the least I am looking to have my radio broadcast an emergency tone at the best, I would like to monitor the temperature from a small wearable device. I’m an Electrical Engineer who used to write firmware so I can handle the interface just not sure the best way to start with the radio side. That’s all “black magic” to me. I have a FCC license for the GMRS but so far nothing else…
I appreciate all the mocking and any direction you guys can provide!

This is a great project if you like projects. If you are lukewarm on projects and just need a reliable working solution, I’d be looking at anything and everything commercial to avoid homebrewing it.

Now, when it comes to implementation you don’t need to dive too deep into black magic side of radio. All you need is switch the radio to transmit by grounding the PTT line and send the payload in form of audio. You can certainly encode digital payload into tones, but in this case I’d just synth the voice message on the sending side so you can receive without need for decoding.

Another option is interfacing one of the off-the-shelve satellite trackers. You can use relays to “press” buttons sending preset messages from your sensing device.

Thanks for the feedback. Can you point me in the direction of any info on the tx signal that would come from the mic? Can I simply put a 0-5V square wave into it to generate a tone?

I’m looking at some commercial solutions too for MURS modules or 27mHz. I want to feed it a simple signal and have it go.

I’m thinking 27mHz might work better through walls than murs if I’m inside a building?


You’ll need to attenuate your square wave to something like 0.3V. Have a pot to further adjust the level.

Different frequencies have different obstacle penetration abilities but RF power may be a bigger factor. You’ll struggle to find a module that will give you 5W like with UV5R.