Ethernet cable (a.k.a., CAT-5/CAT-6 cable) is perfect for extending your I2C sensors using the LTC4311. By doubling up the eight conductors we can get a nice, clean signal to run upwards of 100 feet / 30 meters of distance!
Here's a nice way to connect your STEMMA QT devices to the Ethernet cable, using some hookup wire, heat shrink tubing, and a pair of RJ-45 adapters.




- Cut short sections of solid core hook-up wire, then strip their ends
- Cut and slide the insulation to expose a section of wire in the middle
- Bend each wire to form a tight U-shape
- Insert each wire into the RJ-45 adapter as shown
- Remove the Grove connector from a STEMMA QT-to-Grove adapter (or cut and strip the ends)
- Slip short sections of heat shrink tubing over each STEMMA QT wire as shown below
- Solder the STEMMA QT cable wires to the U-shaped jumpers as shown
- Repeat for the other adapter
Slide the tubing over each solder junction and heat shrink it in place.
Now, you can plug in any length (up to about 100 feet / 30 meters seems to work well) of Ethernet cable, and then plug the STEMMA QT cables into your sensor on one end and the LTC4311 terminator on the other. Connect the LTC4311's other connector to your microcontroller and you're ready to go!
Page last edited March 08, 2024
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