I2C Problem with Johnny-five and raspi-io

---

@mwittig i must say thank you to you for spending so much time in my problem!

so, i have news but first, no, i don´t use pimatic as root, should i? what advantage have i in case of running it as root?
i test it as user pi with ls -lHA /dev/ttyAMA0 and also as root but always the same error.

Then i also digged deeper and found (for me) a solution in the web.

On a other forum (i have forget which…) there was a discussion with the same problem of the /dev/ttyAMA0 and there was the Solution approach to change the:

enable_uart=0 into enable_uart=1

at boot/config.txt

For me now it works!

pi@raspberrypi:/ $ ls -lHA /dev/ttyAMA0
crw-rw---- 1 root dialout 204, 64 Jan 18 20:29 /dev/ttyAMA0
pi@raspberrypi:/ $

Can you test this @mwittig?

Thank you!

P.S. now i have a little other problem. The suply for the MCP are 3,3V from the Pi. I will use them as Input to check the lights of my house (Whether they are on or off). So i return 3.3V on the pins, over the relays. At a device i take i J5 Presence Sensor but i don´t get a high or low signal only flicker. At low i have 0,26V at the Pins and high 3,36V. But nothing change at the device… must i work with pull-down?

Thanks

@Masterplayer said in I2C Problem with Johnny-five and raspi-io:

Thanks for the feedback. It’s great it is working for now even non-privileged. Note, the maintainer raspi-io believes it can only be used as root, but I think he is wrong with this. Unfortunately, he decided he won’t fix the reported issue, so, I’ll document it as a known issue as part of pimatic-johnny-five.

P.S. now i have a little other problem. The suply for the MCP are 3,3V from the Pi. I will use them as Input to check the lights of my house (Whether they are on or off). So i return 3.3V on the pins, over the relays. At a device i take i J5 Presence Sensor but i don´t get a high or low signal only flicker. At low i have 0,26V at the Pins and high 3,36V. But nothing change at the device… must i work with pull-down?

As far as I know the MCP has no internal pull-down resistors, but provides pull-ups. My suggestion is to use an external pull-down resistor of 10k as follows:

Resistor connected to ground. Vcc = 3,3V

@mwittig said in I2C Problem with Johnny-five and raspi-io:

As far as I know the MCP has no internal pull-down resistors, but provides pull-ups. My suggestion is to use an external pull-down resistor of 10k as follows:

Thank you , i will test it and report then.

For Info:

I have check the raspi-io as root and as pi. It makes no difference between the rights. So I use it now as user: pi and it works fine! You only have to do what i post above.