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Witty Pi not connecting via I2C

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(@noons-padlock-6t)
Posts: 2
New Member Customer
Topic starter
 

I have exactly the same issue as presented on this GitHub post by a couple of people: #8

The Witty Pi controls the Pi via its button i.e. powers up/shutsdown the Pi. But does not appear on the Pis 12C bus (nothing visible when I run i2cdetect -y 1)

I2C is enabled in raspi-config. I've used a multimeter to confirm the SDA and SCL pins are well connected between the Witty Pi and Raspberry Pi. Tried with 3x different Pis (Pi Zero W, Pi Zero 2W, Pi 3B+) and 2x different SD cards, same result each time.

Any ideas? Thanks in advance!

 
Posted : 22/09/2025 2:41 pm
(@admin)
Posts: 650
Member Admin
 

You may use multimeter to measure the voltage on SDA and SCL (against GND). Both should be about 3.3V in normal state.

Please also run "gpio readall" to confirm if SDA and SCL are really configured as I2C pins.

If your Witty Pi can turn on your Pi with button, that means its firmware is working, and the same firmware emulates an I2C slave device. It is not likely that the firmware is running while the I2C device is not emulated. 

 

 
Posted : 22/09/2025 3:53 pm
(@noons-padlock-6t)
Posts: 2
New Member Customer
Topic starter
 

 

I think this is showing they are configured correctly?

+-----+-----+---------+------+---+---Pi 3B+-+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 | ALT0 | 1 |  3 || 4  |   |      | 5v      |     |     |
 |   3 |   9 |   SCL.1 | ALT0 | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 1 | ALT0 | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | ALT0 | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 0 | IN   | GPIO. 1 | 1   | 18  |
 |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
 |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
 |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
 |  10 |  12 |    MOSI |   IN | 0 | 19 || 20 |   |      | 0v      |     |     |
 |   9 |  13 |    MISO |   IN | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
 |  11 |  14 |    SCLK |   IN | 0 | 23 || 24 | 1 | IN   | CE0     | 10  | 8   |
 |     |     |      0v |      |   | 25 || 26 | 1 | IN   | CE1     | 11  | 7   |
 |   0 |  30 |   SDA.0 |   IN | 1 | 27 || 28 | 1 | IN   | SCL.0   | 31  | 1   |
 |   5 |  21 | GPIO.21 |   IN | 1 | 29 || 30 |   |      | 0v      |     |     |
 |   6 |  22 | GPIO.22 |   IN | 1 | 31 || 32 | 0 | IN   | GPIO.26 | 26  | 12  |
 |  13 |  23 | GPIO.23 |   IN | 0 | 33 || 34 |   |      | 0v      |     |     |
 |  19 |  24 | GPIO.24 |   IN | 0 | 35 || 36 | 0 | IN   | GPIO.27 | 27  | 16  |
 |  26 |  25 | GPIO.25 |   IN | 0 | 37 || 38 | 0 | IN   | GPIO.28 | 28  | 20  |
 |     |     |      0v |      |   | 39 || 40 | 0 | IN   | GPIO.29 | 29  | 21  |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+---Pi 3B+-+---+------+---------+-----+-----+
 
Posted : 22/09/2025 8:31 pm
(@admin)
Posts: 650
Member Admin
 

@noons-padlock-6t The output of "gpio readall" seems good.

What is the model of your Witty Pi?

Do you have a photo to show how it connects to your Pi, and how it is powered?

 
Posted : 23/09/2025 7:10 am
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