OneWire and I2C issue with power supply

Hello, we order 11 Totem mini lab. but we have problem with power supply. If we plug in power supply I2c and one wire don’t working only with USB power.


can you provide some more information?

  • What I2C device are you using?
  • How pins from device to MiniLab/TotemDuino are wired?
  • Can you show code sketch?

with I2C solved.
OneWire used DS1820 on D3 working only with USB power. Withe PS D3 silnce no data.

Make sure sensor is wired correctly. I2C and 1-Wire communications require 4.7K Ohm resistor between lines DATA and VDD (3.3V or 5V).

What I’d suggest is to check your ground wires – it could be that your PC gives you a ground connection to the sensor through USB, which is of course missing once running from external power supply. The only difference that you should see with USB/power supply is the VIN voltage level (see attached power supply scheme, 5V are taken either from USB or generated from external power supply).