Some of the guys on here are going to love you, Soma. The ones who just love to make solutions WAAAAY more complicated than they have to be.
Using a boost module with input of 3V limits your output to 220mA Max, AND decreases the efficiency of your circuit. I don't know if that will even be enough to energize the receiver, relay, and igniter element together.
The current draw of the receiver is NOT negligible--I work with quality RF receivers of that size and they typically draw around 40-60 mA--I have no experience with the cheap Chinese...stuff...off eBay. Remember, that's a steady current draw. I have to assume you mean to use the unit shortly after you power it up, because your little AA cells don't have enough energy to keep the receiver on standby for an extended period.
The relay's current draw is a unknown. I don't even want to guess at what it draws, being a low-cost Chinese...part. Typically, cheaper relays will draw more power because they're made with less coil resistance. My guess is that it's going to draw more than the receiver, although it will be a momentary draw. The capacity of your battery to supply a momentary current surge might be a problem if you're limited to 220 mA through a booster.
If you simplify the circuit by using (8) AA cells instead of a booster, in an 8-cell holder, the design will be more efficient and you'll have the full current output of the cells when it's needed to fire the igniter.
http://www.ebay.com/sch/i.html?_fro...older.TRS0&_nkw=8X+AA+battery+holder&_sacat=0
I used to work with larger alkaline batteries, but don't know the potential momentary output of those small AA's. I think it's safe to say it's at least 1 A, probably more, which will probably do the job.
You will definitely need to put a resistor on the positive leg of that circuit, between the receiver power and the relay contact. Otherwise, when the relay is triggered, there will be a momentary short on that leg which will drop power to the receiver and the relay, causing the relay to de-energize, which will remove the short and allow the relay to energize again, which will short the input again and make the relay drop out again---the result will be a chattering relay which may or may not allow enough current to finally heat up the igniter element enough to do its job---I'd guess not.
Yes, nichrome wire is high resistance
for wire--but compared to other components, it may as well be a dead short when it's "cold", and the circuit as drawn won't allow it to heat up.
Unfortunately, the ideal value of the resistor, low enough to give maximum current to the nichrome wire, but high enough to keep the receiver and relay energized, depends a lot of how much the receiver and relay--especially the relay--need to draw in order to work.
You might shop around some more and find a seller who lists specifications better. The receivers I use always give the current draw at their operating voltage, with and without relays energized.
