Picaxe is resetting

[toby gross]

I've got a problem with my picaxe resetting, I've written my code when the picaxe powers up it blinks the led twice and stays on. When I've got it hooked up to the 5v regulator which is powered by 12v dc, everything works good, that is on a potato digger with 12v coils etc, when I use a switch on the machine the led blinks which tells me it reset itself, I've got a 100uf cap so there are no spikes in the power source, and a diode for the back emf, could the diode be to small? Appreciate your suggestion, Thanks Toby

 

[BeanieBots]

I've got a 100uf cap so there are no spikes in the power source,

You'll need a lot more than a little 100uF to make a statement like that!
Implementing a micro within a vehical is an absolute nightmare to do reliably unless you have a very good understanding of noise/surges/brownouts and how to deal with them.

This link might give some insights.
http://www.picaxeforum.co.uk/showthread.php?t=8189

As a starting point, post your circuit and we can try to guide you through adding some suppression.

 

[moxhamj]

Try putting a 470uF 16V cap before the 5V reg, and put the 100uF after the 5V reg. Even if there is a spike on the 12V side, the 100uF should keep the 5V stable.

As BeanieBots says, can you pls post the circuit. There is no mention of a 0.1uF, and we don't know what reg you are using and how the diodes are wired nor how thick the wires are or how big the coils are etc etc. A photo would help a lot too.

 

[Dippy]

Read the wise words above.

"I've got a 100uf cap so there are no spikes in the power source,"
- well that's cheered me up this morning.LOL.

So, post a schematic and ALSO tell us about your circuit layout. Stripboard, pcb, putty?

Spcifically what is the power supply? I haven't got a clue about the ins and outs of potato digger electrics. It wasn't part of my MSc Applied Physics course and I'm not going to spend hours Googling. But as BB said; vehicle electrical supply spike/surge suppression can be a pain.... or quite simple if you remember the basics.
And NOTE: a voltage regulator with a couple of caps will NOT prevent a H/F spike (transient) getting through. Components aren't 'perfect'.

I take it you are new to electronics?
On the bright side, with some planning and care you WILL get this working.... whatever it is? (A spud counter? If so, I think it's very appropriate to use chips )

 

[Ralpht]

As well as the caps mentioned by others, a good idea is to use a 100uH inductor in the Picace's power pin. IE: Instead of the Vcc pin going to the power supply, it has the inductor in series with it.

As well, a larger indictor should be at the power input to the entire circuit. About 100 turns of 1mm enamelled copper wire, wound around a 15mm or larger plastic bobbin or even wound around a ferrite rod will do the trick.

I have done something very similar to a camera cct my daughters boyfriend put on his rally car. Before the inductors, the cct constantly had problems with noise and dropouts, now its working perfectly.

In a noisy electrical environment like a car, caps alone won't do it.