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Topic: ATMEGA in a Car !! HELP!! (Read 681 times) previous topic - next topic


Sep 05, 2016, 01:01 am Last Edit: Sep 05, 2016, 01:47 am by Pi0neer
Hi everyone ,
i use ATMEGA 328P in a car

the details ==>>
    i use :16MHz Crystal  ,
             power the circuit with 7805 with 0.33 and 0.1uf connected to Car battery,
             VCC connected with 0.1uf and AVCC too, AREF connected with 0.1uf to GND
             i use Analogue and Digital pins,
             the board contain LCD,7Segments,Bar graph, Shift registers.

The problem ::
the ciruit works well, but if i switched the light or started the engine , ATMEGA going carzy (the lcd give me uknown characters , 7 Segment ,and bar graph too).

I Think::
because the car is a noisy enviroment (Alternator,lights ,horn,etc..).

How can i cancel the noise.
How can i use ATMEGA in noisy enviroment (Cars).



Show us an image of your wiring.
Please show us a schematic of your circuit.

No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.


Sep 05, 2016, 10:48 am Last Edit: Sep 05, 2016, 10:57 am by Pi0neer
i attached it


Sep 05, 2016, 04:55 pm Last Edit: Sep 05, 2016, 04:55 pm by mrburnette
One of the best ways to filter out alternator noise is a DC-DC "buck" convertor...
or similar

12-14 Volts go in and 5V (adjustable) comes out.  Buy one power-rated to match your needs.  IF you wish to use the onboard regulator, too, just adjust the output to around 8.9V-9V and utilize the barrel jack.  Or save power and adjust for exactly 5V and use the 5Volt pin input bypassing the onboard regulator.


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