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[Solved / Archived] WittyPi4 not cutting off power reliable

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Dobby
(@dobby)
Posts: 6
Active Member
Topic starter
 

Hello,

I have noticed that our WittyPi4 does not always cut off the Raspberry Pi 4 power 100% reliably.

When shutting down the Raspberry using the Power button, some data packets can be recognized on the TX before TX is then permanently low. (Raspberry completely shut down)

If I have understood it correctly, TX permanently LOW should be the signal for the WittyPi to pull the gate of the mosfet to LOW. But sometimes it does not do that, the AO4616 gate remains HIGH and the supply voltage of the Raspberry Pi is not switched off (red LED remains on). In this state, the Raspberry can no longer be started "normally" by pressing the button again. Either the battery has to be removed or the power button has to be pressed for ~10 seconds.

How can I prevent the Raspberry from remaining switched on after shutdown and draining the battery?

By the way: Does the WittyPi only check the battery voltage when the Raspberry Pi is powered up or is the voltage also checked when the Raspberry Pi is switched off and the WittyPi is running in power saving mode? I have set the low voltage threshold to 10V. The Raspberry also shuts down at 10V. However, it can then be switched on again immediately. Of course, the battery recovers and the voltage rises slightly when it is no longer under load. Nevertheless, it would be a great feature if you could prevent it from being switched on again. A kind of lockout until the battery voltage returns above an adjustable level. (Or lockout until charging is detected and battery voltage rises above specific level) 👍 

 

Thank you in advance

 
Posted : 27/06/2024 1:37 pm
Dobby
(@dobby)
Posts: 6
Active Member
Topic starter
 

wittyPi.log looks like this, when power is not cut off.

sent 816 bytes received 66 bytes 1,764.00 bytes/sec
total size is 67,876 speedup is 76.96
[2024-06-27 12:16:45] Halting all processes and then shutdown Raspberry Pi...
[xxxx-xx-xx xx:xx:xx] Witty Pi daemon (v4.14) is started.
[xxxx-xx-xx xx:xx:xx] Running on Raspberry Pi 4 Model B Rev 1.4
[xxxx-xx-xx xx:xx:xx] Seems RTC has good time, write RTC time into system
[xxxx-xx-xx xx:xx:xx] Writing RTC time to system...
[2024-06-27 12:17:31] Done 🙂
[2024-06-27 12:17:31] Firmware ID: 0x26
[2024-06-27 12:17:31] Firmware Revison: 0x05
[2024-06-27 12:17:31] Current Vin=13.99V, Vout=5.03V, Iout=0.1A
[2024-06-27 12:17:31] System starts up because the button is clicked.
[2024-06-27 12:17:36] Send out the SYS_UP signal via GPIO-17 pin.
[2024-06-27 12:17:36] File "schedule.wpi" not found, skip running schedule script.
[2024-06-27 12:17:36] Pending for incoming shutdown command...
[2024-06-27 13:18:19] Low voltage threshold set to 10.0V!
[xxxx-xx-xx xx:xx:xx] Witty Pi daemon (v4.14) is started.
[xxxx-xx-xx xx:xx:xx] Running on Raspberry Pi 4 Model B Rev 1.4
[xxxx-xx-xx xx:xx:xx] Seems RTC has good time, write RTC time into system
[xxxx-xx-xx xx:xx:xx] Writing RTC time to system...
[2024-06-27 13:51:02] Done 🙂
[2024-06-27 13:51:02] Firmware ID: 0x26
[2024-06-27 13:51:02] Firmware Revison: 0x05
[2024-06-27 13:51:02] Current Vin=14.11V, Vout=5.03V, Iout=0.1A
[2024-06-27 13:51:02] System starts up because the button is clicked.
[2024-06-27 13:51:07] Send out the SYS_UP signal via GPIO-17 pin.
[2024-06-27 13:51:07] File "schedule.wpi" not found, skip running schedule script.
[2024-06-27 13:51:07] Pending for incoming shutdown command...
[2024-06-27 14:35:59] Shutting down system because button is clicked or GPIO-4 is pulled down.

 
Posted : 27/06/2024 2:43 pm
(@admin)
Posts: 371
Member Admin
 

Persistly keep TXD low should trigger the power cut, unless the SYS_UP signal was not received (via GPIO-17) and the firmware was not in the right state.

Low voltage threshold only define the voltage threshold for shutting down your Pi. As for recovering, another threshold named "recovery voltage threshold" is used. In the software they are configured seperately, and we suggest not to set recovery voltage threshold (significantly) higher than low voltage threshold, to avoid the "lockout" you mentioned.

 

 
Posted : 01/07/2024 5:14 pm
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