[Koil_1] knows he’s forgetful. In order to save himself from any undue harm, or possibly to keep from burning his house down, he felt he needed a timed power switch to run his soldering iron from. He realized he could harvest the relays and timer circuit from a microwave. This allows him to have presets for specific tasks. Considering the fact that you can get a used microwave for free or close to it most of the time, this was a great re use of something that might just go wasted otherwise. Great job [Koil_1].
I could have used this the other night. Luckily my little fire starter didn’t live up to its name.
amazingly, I’ve done this before with the exact same microwave. it really is a great trick!
I use a motion sensor. Works better than a timer for me. It cuts off when it sees nobody for 10 minutes.
i’m using an avr and a relay, three push buttons allow you to select 10 mins for a quick job, 30 mins or 1hr. a small speaker beeps 60 seconds before shutoff and pressing one of the push buttons extends the timer. works great. leaving an iron on over night is not only a fire hazard, but a great way to kill your tips.
I got a couple of time-delay relays a while back. The only problem was that they were not adjustable. I had a choice of 5 minutes or 2 hours. Something like this would have been great to think of before i threw my microwave out a few months ago after robbing the capacitor and transformer.
“I turn it on…and JUST WALK AWAY!”
At first I thought… “how silly; you’re going to have that big circuit board and front panel taking up space on your already overcrowded workbench, when you could buy a much smaller timer from Radio Shack/WalMart for a few bucks.” But, then I realized that, not only can you program it for time for a specific job, but you could also program it for 90% power, 80% power, 70% power… for a specific job.
for the love of $DEITY, if you plan on attempting this, please please read Sam’s Microwave FAQ (http://www.repairfaq.org/sam/micfaq.htm) or other similar resource and follow its instructions to carefully discharge the HV capacitor before poking around the inside of the microwave…this was not noted in the instructable and this capacitor carries enough current to KILL should you touch any of the HV-side components while working in there. This is a great hack but microwave ovens can be dangerous to work with, so be aware.
I once forgot my soldering iron on a wooden table when going for a 2 weeks holiday .. When I came back, the area under the iron had been completely carbonized/pyrolyzed … Amazingly, it did not catch fire. I guess luck was on my side this time. I still have not build a timer, but I’m much more careful.