microcontroller and noisy environment ...

[narbeh_rob]

Hi

I have a trouble in my project....

I design a circuit which use 7 relay and atmel 89c4051 (also 89s52) microcontroller and uln2003 which drive the relays.
This circuit should working near a gas cooker. Everything is ok until the gas cooker electrical spark generators activate for burning the gas on …

At this time system goes in abnormal (reset, halt or change function or do undefined function …) but when I put the system far from the gas cooker it works good …

It seems the electromagnetic generated with the spark generator make the trouble …

Is any body known what is going on, and what should I do to prevent this?

 

[funnynypd]

Try to shield at least your crystal by a piece of metal if there is one. The crystal circuit is always the weak point of any micro system.

also Keep the board clean might help.

 

[phaedrus]

Hi ,

I had recently designed a board for 30kV voltage generation using a PIC. I had made a board with a solid ground plane. Even then ,when there is sparking , if I bring my finger close to the micro without touching, the EMF used to couple to the micro and reset it.

More importantly I had enclosed the entire PCB in a metal box ( Faraday's cage ) with vmany small holes for the wires , instead of one big hole.There was no problem after this.

Hope this helps

 

[sabeti_1990]

hi
1- use large GND for your project
2- be sure that the rellay have bypass diode in their ciol (use bypass diode from uln)
3- use filter in your power supply