LCD16x2 showing Garbage near the Motorcycle

I’m making a digital hub for my motor bike which displays Fuel level, Speed, Engine RPM, Engine Temp. it took me two weeks to assemble all the parts and everything was working great,until now when i tested it for the first time WITH THE ENGINE RUNNING, immediately lcd starts showing garbage… :frowning: a quick search over the internet suggested puting a ceramic capacitor over the power lines on the LCD, and that did not work for me… :frowning:

i tested that specificaly engine is the source of the radiation(possible the alternator).
also, after i placed the capacitor on the lcd, the lcd seemed to work fine near the handle of the bike until i connected something like the hall sensor from the wheel or potentiometer from the tank, everything becomes grabage then…

help please, i did a lot of efforts to put all this together :frowning:

OK, I won't yet put your pictures in a reply and I haven't even looked at them but I will just mention that this is all about shielding and "lead dress". All your wires need to be kept tightly together and you may need to assemble your unit in a DCB.

This is a classic EMC problem. Vehicles pose quite an agressive environment in terms of electrical noise and high voltage spikes which can easily upset electronics.

The electrical noise is most likely due to the way you are powering the system. Please describe. You may be able to use a vehicle 12V DC to USB power supply that has built in filtering. Some of the ones that fit in a car cigar/accessory socket are quite good at noise supression. Does it work OK on the bike if run from AA batteries?

Your sensor leads can also pick up noise but I assume these have no electrical connection to the bike chassis so they can be sreened if needed and filtering can be added.

Other issues you are likely to come across is water ingress, vibration causing havoc with the connectors, and wire fatigue if the wires go into mechanical resonance.

Do not get disheartened, my first project for a car had similar issues but were easily fixed.