A bunch of boards to connect...
John's TNC-Pi2 solved the board space dilemma, but not my power requirements:
|TNC-Pi2||5v (from the Pi)|
I wanted to power the setup off of 12v (13.8v) like the rest of my shack, so the RS-UV3 was all set, but not the Pi2. My solution was a USB power adapter I found on Amazon that could take 7v-23v and step it down to 5v needed by the Pi. The one I decided to use wasn't overly expensive, and could handle 2 amps continuous without a problem.
After running for a few days, It wasn't overly warm even under the heat shrink tubing, so figured I was in pretty good shape for now. (As a side note I took the box out of my attic to take pics after a couple months over over 110F temps, and see no signs of any problems after it's been running 24x7.)
I used an old power cable with a 2.1mm plug I had on hand, however you can buy one of these from HobbyPCB with a pig tail connector. I wired this power connector in parallel with the USB power supply, and then connected them to an Anderson Powerpole connection for a single power connection.
Power's great, but what about the audio?
For the audio I used these Radio connections on the TNC-Pi2:
- Pin 1 (the square pad): Receive Audio
- Pin 2: Ground TNC-Pi
- Pin 3: TX Audio
- Pin 4: Push to Talk (PTT)
...and connected those to the DB9 I/O connector pins on the prototype RS-UV3 board I had. Luckily the blue production boards have SPKR, PTT and MIC pins that you can use, as well as a ground (each pin to the left of those is a ground pin.)
Last but not least the antenna and misc I/O connections
I picked up some SMA connectors on Amazon to run to a hole I drilled in the back of the enclosure (about the only thing that looks good on the back...) I used a nibbler to cut the rest of the whole which as you can see did not go as well as planned as I'm horrible with the dreaded nibbler. The USB connector I also sourced from Amazon as well as the Ethernet jack. Both of those plug into the back of the Raspberry Pi 2 board.
- Hammond Enclosure 1455T2201BK
- Raspberry Pi 2
- TNC-Pi2 from Coastal Chipworks
- RS-UV3 from HobbyPCB
- USB power adapter from Amazon
- 2.1mm power plug
- SMA connector from Amazon
- USB Panel mount adapter from Amazon
- Ethernet Panel mount adapter
- Couple of Anderson PowerPole connectors
Part 2 will be how I configured the Linux and software on the PI.