I am having a problem with some hfs sodium lights. when the lights are a little warm and refire i get a humming in the transformer section (starter , capacitor , transformer 220v) that can last from several seconds to 1 second but it is just devastating to the mega. It dont kill it but does cause it to freeze. i have put zenors on the input voltage along with a 6v mov on the internal regulator played with the caps on the regulator ect. if the mega is within a few feet of this thing it freezes . i have set all pins high internal pullups powered it from a battery and still it freezes running even blink. i loose serial connectivity but i even unplugged serial wires. i have tried multiple megas and unos same result. I took a few scope shots of the interferance being picked up on my scope leads 4 feet away just touching them to a peace it wire.any help with some emf hardening experience would be helpful. i tried putting it inside a steel power supply box left fan on it keeps it cool and didn't help at all. it looks like the period of the signal is 1us roughly so thats 1 MHz . and im seeing peek to peek of 12v which seem very ridiculous hight can anyone share some light on this for me ? I have been trying to solve this and can't seem to get anywhere . Also the transformers ect are inside a steel box already i cant be sure its not the lights making the emi . It only does it on a refire for longer times otherwise its only 1 second or so but still enough to freeze arduino anything . 1us time scale 2 volt amp scale.
You'll need to shield every signal cable, use 1k or 2k2 pullups or so (not the weak internal ones).
Never run arduino cables anywhere near these transformers or their cabling or the mains cables to
them. Extra mains filters may be needed (differential and common mode) on the input to the
supply for the Arduinos... IE lots of precautions everywhere.
Thats the thing i don't even have anything hooked to it yet. just arduino no wires except power tried battery and usb power within seconds it locks up.
anyone have any sugestions on emi hardening the arduino ? or recognise the wave form and have blocking/elimination technique ?
And put it in a metal box, of course.