I am designing a relatively simple system in which I can press a button to turn on a gas burner, to heat up a kettle from the comforts of my bed in the morning. I will have visual of the burner when I turn it on (for anybody concerned about safety).
The solenoid and flame sensors are rather simple with lots of information available online. I would like to ask for help in designing the ignition system. To create a spark, extremely high voltages are needed, which can interfere with Arduinos in many ways. How can I design something that removes this risk? What method/components are recommended and what safety features should I impliment?
I'm unable to get clarity from my research so I would love it if somebody could point me in the right direction.
Post links to the hardware bits you have or plan to use, sensors and so forth.
I would recommend using optoisolators so there is no electrical connection between your Arduino and anything it reads from or delivers control signals to.
Safety? Code for every possible failure of any part of this. And increase your home insurance.
One current project of mine is a high voltage spark generator actually for the purpose of discouraging Martins from entering the engine bay of my car because of their habit of gnawing through cables etc. It is a sort of electric fence type application.
In principle, it is based on a 200 volt power supply of a type used for nixie tubes, which charges a small capacitor, also a small thyristor based circuit similar to that in a CDI (capacitor discharge ignition) and a small ignition coil intended for a 2 stroke motor which I bought for a couple of bucks on aliexpress. The prototype is on an a 7cm x 9cm solder board and it powered by 4 x AA cells. It is controlled by an ATTINY85 and is triggered by PIR detectors which should be suppressed if the car is in motion. The spark appears to be able to jump at least a 6mm air gap which I can alter if necessary by changing the charging time of the capacitor, its charging voltage and its capacity (currently 4.7 uF)
It may be overkill for your application especially if a purpose built piezoelectric gas ignition system but I can publish the current prototype circuit if it interests you. However, it still under testing/development.
No, now you just need to design a mechanism to press the button on it, which is more than a switch contact… you are actually loading force and then releasing it to strike a piezoelectric substance that makes the voltage for the spark.
The easiest thing is probably to hack a Barbeque Grill Igniter. There are electrical (battery operated) ones. A mechanical piezo lighters would need a powerful solenoid.
Optical isolation would protect the Arduino although it might not be needed since the trigger voltage (normally a battery) is low.
Your main safety feature is a flame sensor. My furnace has one but I haven't seen one on a cooktop, and my water heater too. The gas shuts off when there is no flame/heat. My old gas stove has a pilot light and if that goes out gas can flow freely into the room. My friend with an electrically-ignited stove didn't have any protection either, but there is usually a vent over the stove and maybe that's supposed to be good enough. I don't think my (old) gas stove has a flame sensor either, but the ignitor is not a spark, it's a little heating element that stays on whenever the oven is on.
Furnaces have electric ignition but they often use an igniter that doesn't use a spark.
It uses a heating element that sticks slightly into the flame area that heats up hot enough to ignite the gas.
It uses 110v and a bit of current.
They are relatively inexpensive and readily available including at places like home depot.
Spend some time looking at gas furnace systems for RVs, motor homes and trailers. They do exactly what you have described, and in addition have safety circuits that limit the time trying to make a flame.
