MPR121 12 X Cap Touch Shield

[brett burton]

I'm trying to set up the 12 x Capacitive Touch Shield. According to the product page, it uses the same library and code as the MPR121 breakout board. However, when I run the test example, it doesn't appear to find the sensor and none of the sensor points respond. The only tutorial I could find specifically for the shield is for the Capacitive Touch Drum Machine. That involves installing multiple additional libraries for midi support and seem like way more than I need to just get this thing up and running. I saw in that tutorial that I need to run a jumper from the IRQ pin to Digital 4, which I have done, but I'm still not getting anywhere. I'm using an Arduino Duo and I'm running v1.83 of the Arduino IDE.

[adafruit_support_carter]

Sounds like the shield just isn't being seen. Post a photo of your setup showing the solder job on the header pins.

[brett burton]

I'm not sure what my setup should show. I feel like maybe I missed a step, but there doesn't appear to be any wiring in any of the photos with the shield and there's no tutorial that I can find specifically for the shield. I've attached pics, but I'm pretty sure my solder connections are fine.

[adafruit_support_carter]

I'm using an Arduino Duo

Do you mean Due? Please confirm your Arduino board.

The I2C pins are missing. This is how the shield talks to the host board. Do you not have mating connections on your board?

i2c_pins.jpg (86.67 KiB) Viewed 216 times

[brett burton]

Sorry, my bad. It's an Uno R2. The Italian names confuse me sometimes.

[adafruit_support_carter]

Since the R2 does not have the I2C pins like the R3 does, you'll need to wire them up as follows:
A5 = SCL
A4 = SDA
You can do that by adding some connecting wires as shown below:

i2c_wiring.jpg (87.32 KiB) Viewed 197 times

[brett burton]

Awesome. Thanks. Going to try this right now.

[brett burton]

It worked immediately. Thank you!