I have a problem connecting to the Strompi. I will try to explain what is going on.

Strompi installed on Pi4 running your Bookworm image on the SD-card.

From /home/pi/StromPi3_Scriptfolder_2023-12-13/home/pi/StromPi3_Scriptfolder_2023-12-13 I am running python3

The following output is generated:

pi@raspberrypi:~/StromPi3_Scriptfolder_2023-12-13/StromPi Status/V1.73 $ python3
Traceback (most recent call last):
  File "/home/pi/StromPi3_Scriptfolder_2023-12-13/StromPi Status/V1.73/", line 145, in
    sp3_ADC_Wide = float(serial_port.readline(9999))/1000;
ValueError: could not convert string to float: b''

I do not understand what is going on here. Perhaps the Strongpi is not running in some way?

Do you have any advice on what to do?


Thanks Jos


02.05.24 12:12

Hello Jos,

This error message usually indicates a problem with the serial communication.
Scripts running in the background or other connected hardware using serial communication can cause this problem.
If you do not have a script running in the background or hardware connected that uses serial communication, we recommend first disconnecting the StromPi completely from the power supply and removing the CAP jumper for a few seconds. If this does not help either, you will need to reflash the StromPi's microcontroller with the latest firmware. You can download the firmware and instructions for flashing in our download directory.

Best regards 

Tim (Joy-IT)


02.05.24 14:55

Hello Tim,

We have no communication running in the background.

As advised I disconnected power and removed the CAP jumer. This did not help.

Next I went to reflash the controller with V1.8 firmware. The results are listed below.

pi@raspberrypi:~ $ stm32flash /dev/serial0 -w RB-StromPi3-V1.8.bin -b 9600
stm32flash 0.7

Using Parser : Raw BINARY
Size         : 30372
Interface serial_posix: 9600 8E1
Failed to init device, timeout.

As shown a device timeout is generated.

I downloaded RB-StromPi3_RaspberryPiOS-Bookworm-Lite-64bit_2023-10-31_shrinked.img from your site and wrote that to my SD-card. No other software was installed using /dev/serial0, so what could cause this odd behaviour?

Any other steps I can take?

Best regards and thank you



02.05.24 17:55

Hello Jos,
if even reflashing the microcontroller fails after several attempts, we must unfortunately assume that the microcontroller is defective.

In this case, I would recommend that you contact your dealer to get the StromPi replaced.

Best regards 

Tim (Joy-IT)


03.05.24 08:47