To use this repo, you will need a built PAPRA PCB Assembly, either the surface mount version or the thruhole version. Check this repo for more information:
https://github.com/tetrabiodistributed/papra-pcba
and also check this out for build instructions for the thruhole board:
https://tetrabiodistributed.github.io/papra/
Now you need to know what kind of fan you're pairing the board with. The current firmware has three different sections for fans, like:
// MAP FOR CUI 154 BLOWER
// Limits the min pot value Voltage Min PWM Percentage
// const int minPWMfull = 108; // 11.85V 69 >77%
// const int minPWM75p = 112; // 11.10V 72 >54%
// const int minPWM50p = 115; // 10.62V 77 >33%
// const int minPWM25p = 120; // 9.75V 88 >10%
// const int minPWM10p = 250; // 8.40V 110 >0%
// These values were determined emperically by adjusting the input voltage and dialing the PWM down until motor stall
// MAP FOR NM33GA-12Q-AT BLOWER
// Limits the min pot value Voltage Min PWM Percentage
//const int minPWMfull = 10; // 11.85V 69 >77%
//const int minPWM75p = 11; // 11.10V 72 >54%
//const int minPWM50p = 15; // 10.62V 77 >33%
//const int minPWM25p = 20; // 9.75V 88 >10%
//const int minPWM10p = 25; // 8.40V 110 >0%
// These values were determined emperically by adjusting the input voltage and dialing the PWM down until motor stall
// MAP FOR SEEED ESP32-C3 SANYO BLOWER
// Limits the min pot value Voltage Min PWM Percentage
const int minPWMfull = 219; // 11.85V 69 >77%
const int minPWM75p = 222; // 11.10V 72 >54%
const int minPWM50p = 223; // 10.62V 77 >33%
const int minPWM25p = 225; // 9.75V 88 >10%
const int minPWM10p = 232; // 8.40V 110 >0%These values allow the potentiometer to be adjustable throughout the full range for each of the different fan types. Right now, the code is set for the SANYO blower, since that particular fan has what we've found as the best combination of battery life and output pressure/flow (ie, it meets or exceeds what we need for flow while still having multiple hours of battery life).
Once you have the board built and attached, you should be able to flash using either ino module (thruhole for the thruhole board, surface for the surface mount board).
Firmware is intended to be loaded on this PCB Assembly: https://github.com/tetrabiodistributed/PAPRA-PCBA
Use the following arduino settings, change the chip to match the one you are using.
Note: for ATtiny204 and ATtiny214 have 2K flash memory for program space. The preprocessor for TWOKFLASHCHIP must be uncommented prior to compiling. See Line 9.
We have encountered the following issues when building a board:
- The buzzer is always buzzing when I put the battery in!
Check that you have a 100k resistor on R3 instead of the 10k resistor. A 10k resistor on R3 means that the firmware is always registering that the battery is empty, and the buzzer sounds when the battery is empty.
- Am I using a 330k resistor or a 300k resistor for R2?
330k. We should have fixed all the BOMs by now, but just in case...
- When I attach to a voltage source (not a battery, but a power supply), the voltage is strange!
Check the solder joints, especially around R2 and R3. A cold solder joint can cause the circuits to behave strangely.
- Some of my LEDs aren't lighting up!
Check those LED solder joints. We try to put the LEDs on first on one side of the board, then put everything else on the other side, but that's definitely a matter of taste.
- My LEDs are always lit, even if the battery has gone down to zero! What's going on?
Check that the 100k resistor at R3 was properly soldered to ground; if that resistor isn't grounded properly, then the firmware will read the battery as being constantly full, even if it's drained. This particular error can be very bad, since it also means that the controller chip where the firmware has been installed may be damaged, since the chip is rated for 3.3V and the lack of ground at R3 may cause a full 12V to go to the chip.