Trouble connecting Pi 2 to Rainboduino

I have hooked up a Raspberry Pi 2 to 6 Rainbowduinos (ARD117D2P) that I bought a few years ago and have been using with great success with an Arduino. Here is what I did

  1. Using the Pi’s pull up resisters I connected SLA to SLA, SCL to SCL and GND to GND.
  2. Rainbowduinos respond on addresses 4-8 (verified on the Arduino)
  3. I followed the directions for enabling I2C on my PI (see: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-i2c )
  4. When I run “sudo i2cdetect -y 1” I get different results every time. Random addresses show up:

pi@raspberrypi ~ $ sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- 04 05 06 07 -- -- -- -- -- -- -- -- <lines deleted> pi@raspberrypi ~ $ sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- 04 -- 06 -- 08 -- -- -- -- -- -- -- <lines deleted>

A (node.js) stub of a program fails to communicate with the the Rainbowduino. I get “Error: Cannot write to device”.

Quite a bit has to be working to have devices 4-9 show up in the i2cdetect output even if intermittently but soemthing is wrong.

Has anyone had better luck connecting the Rainbowduino to the Pi? Has anyone see a problem like this?

Thanks so much.

Ken