HTCC-AB01 I2C pull-up

#1

Hello,

I connected these sensors to a HTCC-AB01 board:

  • SHT3X (Humidity, Temperature)
  • BMP180 (Barometric Pressure, Temperature, Altitude)
  • INA219 (Current)
  • VL53L0X-V2 (Laser distance)
  • GY-US42V2 (Ultrasonic distance)

Interestingly the first measurement after a Reset is always successful, but the subsequent measurements are collecting wrong data. Any one of these sensors is working fine when it is connected alone.
Just BMP180 comes with a Pull-Up resistor and I added 4,7k Pull-Ups for SCL and SDA, but this is just a guess… Is the problem related to the Pull-Ups or something else? If yes, how do I have to size the resistors?

#2

please refer the picture.
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#3

thanks! Could you please elaborate more on this? What does the picture tell me? Are these the resistors I have to use or are these the resistors the board comes with?

#4

I thinh its not a problem of pull up resistors.

The communication ist probably the cause of the problem!

You must close the fist communication and then start the next communication, probably it is advantageous not to use a library and then program the i2C communication directly!

E_T

#5

hi,

If you use the BMP180 produce by heltec,There is already two pull-up resistors for sensor board.

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