Hi everyone,
I am experiencing an issue with a Witty Pi 2 where the Raspberry Pi 4 cannot be powered on using the button. Shutdown via the button works reliably, but powering on does not. Also the set timer in the Witty Pi menu has no effect on startup/shutdown mechanics.
Setup
- Raspberry Pi 4B
- Witty Pi 2
- Power supplied only through Witty Pi
- Tested with both power bank and wall adapter
- No direct power connection to the Raspberry Pi
What works
- System boots normally when power is initially applied
- Shutdown via long button press works
- I2C is working (
i2cdetectshows device at 0x68) - Witty Pi software is installed and accessible
- GPIO access and wiringPi verified (on a working system)
Problem
- Short button press: no effect
- Long button press: triggers shutdown correctly
- After shutdown: Raspberry Pi cannot be powered on using the button
Tests performed
- Verified correct physical connection (board properly seated on GPIO)
- Ensured Raspberry Pi is powered only via Witty Pi
- Tested different power sources (power bank and wall adapter)
- Executed and configured schedule via
wittyPi.sh - Ran
init.shafter installation - Performed clean shutdown using
sudo shutdown -h now - Tested long button press (5–10 seconds) after shutdown
- Verified RTC communication (I2C shows device at 0x68)
- Verified GPIO functionality
Observation
The button input clearly reaches the Raspberry Pi (shutdown works), but does not seem to trigger the Witty Pi controller to power the system back on. I am running out of ideas right now about the actual cause of this issue.
Unlike the newer models of Witty Pi, Witty Pi 2 does not have an MCU onboard, and the switch latching is implemented with discrete components.
Your testing result does not show a fully functional switching: only long-press works. Long-press is suppose to force-cut the power, instead of shutting down the system gracefully.
You may want to double-check the green jumper: the jumper cap should be placed at the "Halt by GP4" position. If it is not there, that explains why short button press can not shutdown the system, but it can not explain why short button press can not boot the system up.
Considering Witty Pi 2 has been discontinued for about 7 years, it is rather old hardware and the circuit onboard may already be malfunctional.
The jumpers are placed as followed:
defaultset to ON and OFF (both tested)
halt by GP4enabled
LED on GP17enabled
dummy loadtested both ON and OFF (both tested)
I thought Witty Pi 2 and Raspberry Pi 4 are compatible as stated on your Website: https://www.uugear.com/product/wittypi2/ wiringpi is installed and functional. Is it rather a hardware or software issue? How about the ATtiny controller?Is there any additional initialization required for the ATtiny controller to enable power-on via button?