Building a Hammo Can

Recently, the STEM Amateur Radio Club lost a pico balloon (N4TVV-2), so I decided to build a "Hammo Can" to help in the hunt. It's a 50-caliber ammo can containing a 15Ah LiFePO4 battery with BMS, a Raspberry Pi Zero W 2, a 2.8" screen, an AIOC, a Baofeng AR-5RM, GPS dongle, a voltage monitor, USB ports, switches, and miscellaneous hookup components.

The completed Hammo Can setup

Components and Setup

The Pi runs DigiPi software, as it already does everything I need for APRS logging. Just complete the first-time setup and you're good to go. At home, it connects to a convenient antenna, and on the road, I have a port to connect whatever is easiest in the field.

Internal layout showing the battery, Pi, and radio components

Power Management

I also have a port for solar hookup with my accompanying panel. Since the radio operates mostly in listening mode, it's more than enough to fully charge the battery on most days.

Solar panel for field operations

Field Testing

Field testing is still to come. It does work great around the house during initial testing.

Future Plans

I plan to replace the AIOC and AR-5RM with an SA828S-V and a CM108 sound card. I would like to repurpose my radio and AIOC for other projects. I have several CM108 sound cards that I've modified and tested with an SA818, which is only a 1W module compared to the 2W SA828.

SA818S-V and CM108 sound card test setup

I also have to replace the temporary panel made of modeling styrene with a "real" one cut from wood or metal. I'll need to borrow a laser cutter or cnc for that.