Hi, I am diagnosing a problem with my ultrasonic sensors. At least one is being reported as 'obstructed' but operating the car and listening for the pulses ... well not a happy situation for one. I just took delivery of piezoelectric elements and verified they generate a usable signal with my VOM. My next goal is to come up with a cheap, shielded cable pair. My plan is to get unshielded Cat-6 (or Cat-5) patch cord about 10' and a pair of RJ-45 sockets. One socket with the piezo disc will have the piezo wired to a signal pair and the other three pairs, tied together. The other end RJ-45 will have an audio jack for the signal pair with the remaining three pairs tied together and to a ground. My thinking is the three other pairs will be a shield against EMI from the signal pair. This should minimize any EMI from my Tesla. @hobbit does this make sense? Initially, I may just wire up one signal pair and let the other three pairs float. If I see significant noise, I can then ground the other three pair and try again. Thanks, Bob Wilson
Cat 6 offers limited EMI interference capabilities which is why distance from sources is important in installations. Typically, I use emt conduit as an install method to offset that as the conduit is grounded. Obviously, that is not compatible in your situation so I would suggest Cat 7 as an alternative. "CAT7 is a newer copper cable specification designed to support speeds of 10Gbps at lengths of up to 100 meters. To achieve this, the cable features four individually shielded pairs plus an additional cable shield to protect the signals from crosstalk and electromagnetic interference (EMI)."
