23-06-2019, 03:04 PM
You need to shield or short circuit the radio frequency "noise" generated by the Seven's system.
This "noise" is picked up by any wiring, even that on your chip, and it interferes with the signals carried by that wiring.
It may not work, but I would put the chip in a metal box which is electrically connected, preferably bolted to, the "earth" system of the car, and fit suitable capacitors across the wires carrying signals and power to the chip.
As small an opening in the box as possible, the capacitors need short wires, as close to the box as possible.
Capacitors short circuit AC frequencies, the suitability of the capacitor size depends on the frequencies you want to filter out.
You need to know the frequency of the signal going to the chip - the pulses you want to count, and don't use a capacitor that will filter those out.
Easy to try, if you can acquire a few capacitors.
If it looks like working, you could use shielded wiring to further improve the signal/noise ratio. TV aerial co-ax, for example.
This "noise" is picked up by any wiring, even that on your chip, and it interferes with the signals carried by that wiring.
It may not work, but I would put the chip in a metal box which is electrically connected, preferably bolted to, the "earth" system of the car, and fit suitable capacitors across the wires carrying signals and power to the chip.
As small an opening in the box as possible, the capacitors need short wires, as close to the box as possible.
Capacitors short circuit AC frequencies, the suitability of the capacitor size depends on the frequencies you want to filter out.
You need to know the frequency of the signal going to the chip - the pulses you want to count, and don't use a capacitor that will filter those out.
Easy to try, if you can acquire a few capacitors.
If it looks like working, you could use shielded wiring to further improve the signal/noise ratio. TV aerial co-ax, for example.