picaxe + hqi

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fermassa

New Member
i have a problem with this..

i need to turn on a hqi 150w.
i used irf520, tip41c, darlington array, etc.. to activate relay conected to the hqi..
but i can´t maintain activated the relay.

with irf520, tip41c, to 5v directly it works ok.. the problem is when i use the pic out.

any suggestion?
 
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BeanieBots

Moderator
I don't fully understand your question.
What is hqi 150w?

You say it works at 5v.
What voltage is the relay coil?
Double check you have collector and emitter the right way round.

When it doesn't work, what is the voltage on the PICAXE output pin?
 
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Dippy

Moderator
If it is that then when switching on you could could have a honking great transient which upsets the PICAXE. And I hope you have complete isolation of supplies. It could even be a woosie ground.(Sorry, 0V line for oldies).

Confirm the component and post your schematic. The combined Forum Crystal Ball is dull today.
Stick your schematic/drawing on somewhere lik Tinypic and provide us with a link.

The solution is probably quite easy but you haven't provided anywhere near enough information.
 
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fermassa

New Member
Sorry..

I upload an image with some examples..

http://i17.tinypic.com/4qdwkux.jpg

i test with this circuits without result, i only works when i apply directly 5v like "test b2".

All circuits without the lamp conected to the relay works.
 
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papaof2

Senior Member
"All circuits without the lamp conected to the relay works."

This is the probably most important piece of information. It indicates that there is most likely a large power spike when the lamp is turned (the lamp's cold current is several times its hot current). That spike is affecting the PICAXE.

Physical separation of the PICAXE and power wiring, additional filtering at the PICAXE, and ensuring that ALL unused pins on the PICAXE are connected to 0v or +5v via a resistor should help.

John
 
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fermassa

New Member
i test that with a 12v fan, and i have the same problem..

i can´t turn on 12v fan with the irf520 either..


whats wrong?

 
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inglewoodpete

Senior Member
Try replacing the lamp or fan with a 100 ohm resistor (minimum 1.5watts) or a MUCH SMALLER 12v lamp bulb. The problem still appears to be interference due to the high transient current (lamp) or commutator noise (fan).
 
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BeanieBots

Moderator
What are you using to power the PICAXE?
Try using using batteries to eliminate supply noise issues.
Make sure you have good decoupling (0.1uF + 10uF) on the supply rails with the 0.1uf as close as possible to the PICAXE supply pins.

You are not helping us to help you.
We need to know DETAILS.
When you say "can't turn on", WHICH part of the circuit is failing?
Does the PICAXE pin put out 5v?
Do you think the PICAXE is resetting?

All the circuits you have shown are very 'standard' and all of them work so your problem is going to be something very simple.
 
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BrendanP

Senior Member
Metal halide lights are usually used for the growing of 'medicinal herbs' aka Ganja. or so Ive been told......

I was re-reading the post, I gotta laugh... he's even got the fan which is needed to vent all the heat the halides generate. The plants have a optimum ambient temp for growth of around 22 C.

Try a temp sensor so the fans only come on when needed. Get a C02 sensor and have a try with C02 injection. You'll see some amazing rates of growth then. The picaxe could monitor the sensor and open the solenoid valve on the C02 bottle as needed.

I guess I shouldnt presume anything, its probabaly just tomatoes being grown. Im probabaly just projecting my own mispent youth onto others.

Be carefull, a house fire due to a electrical fault guarantees police attendance!

You could hook a smoke detector up to the picaxe and when if it was triggered in the event of a fire the picaxe would open the C02 bottle to extinguish the fire. Just dont be in the room because you might get 'extinguished' as well due to the lack of oxygeon.



 

Edited by - BrendanP on 10/08/2007 08:44:20

Edited by - BrendanP on 10/08/2007 08:57:33
 
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Dippy

Moderator
Lawsuit heading your way brendan :)
And if growing that stuff you don't need a smoke detector. Just put Pete Doherty in a cage nearby - if he falls off his perch then your ganja is on fire.

BACK to the PLOT >
As said by me at the start and by all the others , it's probably a spike/transient. You haven't shown the power conenctions to your PICAXE circuit - this is where we suspect the problems lies.

Any big dip/spike can cause the PICAXE to reset or have a fit.
Do you have any spike suppression?
Do you have a juicy decoupling capacitor near PICAXE supply pins?
Do you have a nice 'strong' power supply?
Do you have a fat capacitor at the Vin leg of the relay? (So that the capacitor takes the edge off the initial start pulse)
If you are using a common ground are the ground lines nice and thick? (Right back to PSU).

Without more info we'll just go round in circles with everyone repeating everyone else's answers (which happens a lot on this forum).

So let's have a schematic of the whole PICAXE/relay circuit including component values. And tell us the specification of the power supply.

Edited by - dippy on 10/08/2007 09:00:28
 
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BrendanP

Senior Member
And his name is PepeLePeu. Who's PepeLePeu ?
A skunk. What strain of ganja is grown indoors under halides? Skunk. This guy is a classic.
Oh innocent, picaxe to what nefarious purposes you talents are bent!

 
 
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