18650-Backpack
- 9V regulator... no more Fatshark alarm!
- Settable voltage alarm. Default 3.10V with a secondary alarm at 3.00V (0.10V below set alarm voltage). Configurable through the UI.
- Beeper alarm and flashing OLED.
- Monitors over all voltage, cell 1 and cell 2. When using a Fatshark battery pack without a balance wire the cell voltage is pack voltage divided by 2. This does not mean the batteries are balanced.
- Current sensor.
- mAh consumption.
- On time.
- Retains on time and mAh when powered down. Can be cleared for a new battery by pressing any button while plugging in the battery.
- 12 character callsign. Configurable through the UI.
https://www.youtube.com/watch?v=n1eo8pUAjkk
Bill of Materials
The below links are give for reference so you know what to search for from your favourite/local supplier.
A hot air rework station (such as the 858D linked below) is required if you use the following BOM. I used the Digispark Attiny85 and INA219 break out boards as donors for the 18650 Backpack. This make life easier than ordering ALL of the components separately.
https://www.banggood.com/858D-220V-Hot-Air-Soldering-Rework-Station-Handle-Handle-Stand3-Nozzles-p-1129100.html
Flashing the Attiny85
The below can also be done with an Arduino Nano.
https://www.instructables.com/id/Program-an-ATtiny-with-Arduino/
- 1 - Ground
- 2 - D11
- 3 - D12
- 4 - D13
- 5 - D10
- 6 - +5V
Core and Libs