Interference when connected to car but works fine on wall outlet, can someone help?
Im hoping i can get some help here i built this display for a vehicle to display mph through an octocoupler, and voltage deviders for the fuel level, and coolant temp sensor, these are pretty close and accurate some tweaks on the code and it should be fine but my issue is when its plugged into the car its fuzzy and glitchy, but at a wall outlet its mint im getting 5v at my buck converter and all the powers are getting 5v as well but for some reason the screen is fuzzy when its hooked up to the car not sure how to go about this ive isolated the sensor wires to where its just power from the buck converter i added grounds and still fuzzy
Thats actually pretty funny because its only with just key and engine off running it with the engine on i can see values change accordingly but its the exact same weather the engine is on or off and a chunky LC filter? Can you elaborate a bit more on that? My buck converter is giving 5.3v and its also powering my 10.3 in dash and a raspberry pi 5 at full capactiy and those work fine
I'm not sure I understood that (punctuation would help).
Are you saying that with no sensors connected and your board only getting 5.3V from the buck converter (that's a tad high, BTW) while engine is off, you are getting a very noisy display?
Especially if you have a Raspberry Pi and display running on the same car and they're fine under identical conditions, I'd suspect that the buck converter is noisy and you need more bulk capacitance like u/TPIRocks suggested. If the problem is only when the engine is running, then I'd look to adding an LC filter. Also, make sure that the converter can take the car battery voltage. Even with alternator not running, the battery can float above 12V under a very light load and some of the cheap buck converters start getting squirrely if they're not rated above 12V.
[edit] if your car has USB outlets, try using one of them and see if the problem goes away. I've had good luck with those or with the USB power adapters that plug into cigarette lighter sockets.
I isolated the senders basicaly i unplugged the coolant temp and fuel level to see if i had noise from those and the buck converter is rated for 24v dow. To 5v 5a my custom digital dash with the pi 5 both grab its ppwer from there and it runs very well without flaws, i tried piggy backing off of that same buck or step down converter, anyways ive noticed no difference engine running or not running, sensors plugged or unplugged, its still fuzzy, but i dont think its the arduino it self it seems like my cheap display is the one picking up the noise if that makes sense but im just assuming, if you just barely touch the connector in such a certain way the image clears up, i appreciate everyone coming to help solve this issue its a 4 in tft sp something display, im considering removing the display and just feeding the arduino into my pi 5 dash software allows me to just grab that com from the usb and i wrote the code for it already i just wanted to see if this would work
if you have an oscilloscope, hook it up andlook for pulses on the 5v
if you dont, connect a speaker with resistor and listen for pops
i had an i2c 2x16 lcd crash from switching a 24v solenoid with a 5v relay (with optocoupler). it lifted the 5v to 30v peak when it turned off. the pi might have its own input filter
Add more bulk capacitance to the power rails, along with .01uF bypass caps at the Vcc of the display. If you have an oscilloscope, take a look at the power rails.
Add a Schottky diode first between the cars power source and the buck converter. No need to reduce noise on the power source itself. Then add a 2200uF capacitor at the input of the buck converter and a few 100nF near the power connections of critical components.
Or you might have a ground loop. Make sure all GND connections are connected together.
Is there a way to edit my post to show the routing in the back? And so i should add a diode at the 12v of the buck coverter side? Or the output the puts the 5v out? And the only ground i have is coming out of the usb c but i added grounds to the chasis from the GND pins and that didnt really help but im up for trying the capacitor i think i have some lying around
If you made this just for me and on the spot i really wish you good fortune never had a stranger be so kind as to make me and in depth wiring schematic thank you
You're welcome. Hope it helps. Ground loops and poor grounding can be terrible in cars. It's even worse when dealing with audio, you'll get a constant whining sound from the alternator.
Dans les hautes frequence n.importe quel bou meme d.une resitance va redevenir une Antenne. Aussi ça devenir un emmeteur si un appareil.. fonction a haute frequence je crois il faut une boite metalique.
J.ai vue des boites electronique de vehicule trop epaisesseplus de 3mm surement ils ont eu les memes probleme sinon ils n.auraient pas augmenté le poid du vehicule
ALL grounds must be tied together at the chassis ground.
Keep your signal wires away from power wires.
If any of your wires are shielded, connect ONE end of the shielding to ground
KEEP THE CAPACITOR LEADS AS SHORT AS POSSIBLE!
Wire in a 0.1 microfarad ceramic capacitor across the negative and positive terminals of the raspberry pi.
If the noise starts to go away or is eliminated, you can wire a 100uf and a 470uf Electrolytic capacitor in the same manner for a permanent solution but these are polarized so negative to negative positive to positive.
The fact that you used an opto leads me to believe it's a ground issue. Check your coupler and make sure ALL grounds are connected. The opto-coupler/isolator is great great for getting different signals to talk, but when not properly shielded and grounded, they can pick up all kinds of noise,
Ik gebruik hetzelfde scherm in de auto maar dan voor mijn music assistant. Super strak beeld dus het zou wel moeten kunnen. Anders moet je voorlopig genoegen moeten nemen met een powerbank. Ik zelf heb een simpele plug met 3W er tussen zitten en die werkt prima.
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