The littleBits roller switch module, part number 650-0019, has a little lever with a wheel, and activates when something moves past it. You can also flip the mode switch to make it turn off when the lever is pushed in. Try that mode with an LED to make a fridge light.
Product Specifications:
- Dimensions (mm): 20.0(H) x 77.0(W) x 149.0(D)
- Product Number: i19-ROLLERSWITCH
- Product Weight: 0.01 lbs (0.005 kg)
- Recommended Age: 8+
- SKU: LB-BIT-i19-ROLLERSWITCH-v03
- UPC: 859477003898