I'm building a controller for my gas burner to be used for homebrew beer making.
I want to provide an auto-ignition function and have been looking at various options - all of which use an inductor to generate a high voltage which generates a spark across a suitable electrode located close to the burner or a pilot light.
I'm comfortable in putting together such a circuit and controlling it from an Arduino. My question relates to the possibility of this high voltage finding its way back from the metal burner, though the metal plumbing and into the controlling electronics and burning them out. Is this a possibility? If so, any suggestions on how to mitigate this? I'm using a simple 2-connector wall-wart PSU, so there's no earthing here.
Thanks for any advice and suggestions.
Yes, high voltage discharges can scramble or destroy nearby, unprotected electronics.
You can use optoisolators to conduct signals without electrical continuity, and of course, nearby sensitive electronics should be inside a grounded metal box.
Post a wiring diagram.
Providing you are very careful to earth everything that could possibly have the high voltage on it, and earth everything else just to be sure then I don't think the high voltages will be a problem. I am MUCH more concerned with the possibility of gas leaks and possible explosions with what you are trying to do.
Why not use an RV gas hot water heater control unit? All in one and runs on 12 volts.
Why not use a little pilot flame that You ignite manualy and burns all the time. Your project will then control the gasvalves? That way gas owens worked in the past. The pilot flame garantes that any eventually leaking gas is burned safely immedeately instead of collecting and later cause a big explosion.
Thank you everyone for your suggestions.
I'm very familiar with handling and plumbing very high pressure gases and so will take the utmost care.
One of the benefits of using natural gas is that the pressure is about 0.25 psig and so, although leaks are still a big concern, they're not as bad as using, for instance, acetylene at 2,500 psig.
I was planning to use a pilot light AND and an igniter to light it.
I was hoping that someone might have tried using a high voltage igniter - it's an expensive experiment if it doesn't work
I assume you'll use a mains powered HV (spark) generator. These are in common use in the UK (I can't read where you're based). If you use a digital output from your Arduino to energise a relay, and that relay switches mains to the spark generator then you will have sufficient isolation to protect your sensitive parts from the fat sparks.
The mains supply to the spark generator will need an earth, and there must be a return path to this earth point from the spark electrode. My advice is to NOT put the Arduino (and other low voltage stuff) into the same enclosure as the HV.
Hope this helps.
Wouldn’t a low power electric heater be easier /safer ? You don’t need high temperatures for brewing and the incidence of a flame on part of your tank may overheat it locally and stop fermentation ?
Note you’ll also need gas control ( solenoids) and flame detection. In the UK you are not allowed make that stuff , check for your location too.
Current gas ranges use a ceramic coated heating element to ignite the gas.
Not going to cause electrical issues with one of those.