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Birthday Project - Bacon-makin' alarm clock

Discussion in 'General Electronics Discussion' started by neurotictim, May 15, 2012.

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  1. neurotictim


    May 15, 2012
    Hi guys and gals, first post here after lurking for a while. I need help with a project I decided to do for my g/f's birthday - an alarm clock that cooks bacon.

    I caught the idea from a list I found whilst perusing the interwebz, here is a link to what I'm talking about.

    I've decided to refine the idea some, and I need help with this part.

    As it stands right now, I have a box, 16" wide x 12" tall x 7" deep, ready to go except for the electronics. I spent most of yesterday evening making it - woodworking is a hobby of mine - and I'm pretty happy with it. I have PLENTY of room for the electronics, and a separate section for lamp/fan/bacon - to prevent the heat from the light screwing with anything, primarily.

    So here's the goal - I'm going to go buy a couple of alarm clocks to disassemble, and find out what triggers the alarm. It's hopefully a straight DC voltage, but realistically it's probably a clock pulse to turn on an amplifier in the clock. I'm going to try to find some older clocks in a thrift store to make it easier.

    At any rate, the clock part should be pretty straightforward - I can mount the display in a cutout and mount the controls on the back of my box. I've intentionally left the box unfinished, with no top or front yet to accomodate the various styles I may have to play with. Taking apart a clock and figuring out how to mount it will be the easy part.

    So my questions are going to follow more on the other side - the cooking side.

    The idea is to power a relay with the alarm signal - whatever that may be - that will close and allow 110V to power a 75W halogen incandescent flood bulb. There will need to be a timer circuit, though, that will shut off power to the relay (thus opening the circuit) after a set period of time - 5 or 10 minutes, I don't know yet until I get the bulb mounted and a tray made so I can test it. Taste test, of course. :D

    I also want to power a 60mm AC computer cooling fan from that same light bulb feed, as an exhaust to spread the bacon-y goodness out into the room. However, I want to time that to come on just a couple of minutes before the lamp turns off - having it on the whole time will bring temps down and prolong the heating process, which I don't want. So I'd need to time the fan to come on 3 minutes into the 5 minute cooking cycle, or 7 minutes into the 10 minute cycle, depending on how long it takes to heat.

    (BTW, I'll be using pre-cooked bacon and essentially just heating it up with the lamp - uncooked bacon will go bad if left overnight at room temp)

    After the cooking cycle, if the smell isn't enough to wake her, I'd like to have an audible alarm of some sort go off. Ideally I would be able to record a sound that could play repeatedly (think pig grunts, lol), but any sort of alarm would work.

    The goal is that the g/f should be able to place a couple of strips of bacon in the pan at night before going to bed, set the alarm for either 5 or 10 minutes (depending on what I figure out for cook time) earlier than she wants the audible alarm to go off, and call it good. Alarm trips, turns on light, which begins heating the bacon. A few minutes prior to shutting off, the fan kicks on and scents the room. After proscribed cooking cycle, the lamp and fan turn off, and the audible alarm goes off. She gets up and shuts alarm off manually, then retrieves her bacon.

    So I guess the questions start here.

    Assuming that this evening I can get a couple of alarm clocks and find a signal voltage when the alarm trips, what would I need to make this happen? I know all about repairing electronics, but engineering them from scratch is still beyond me. I can imagine perfboard, resistors, and a few 7555s are in my future, but can anyone help me with talking me through creating the circuitry I need?

    Am I even being realistic? Am I asking too much from an alarm?

    I've got a GREAT electronics store locally - Priest Electronics - and those guys know their stuff, but I'd rather have a good idea of what I'm going to need before I go in and soak up a bunch of their time.

    I've got about a week till her birthday, I'm hoping to be able to assemble everything this weekend, with any luck.
  2. neurotictim


    May 15, 2012
    So upon further research, I think maybe it would be easier (and more robust) to get a delay-off timer (like the IDEC GT3F) for the lamp, and to wire a delay-on timer (like the Omega TD-69) so that it delays the fan powering up for the first part of the cooking, and then kicks on, and power gets cut when the GT3F shuts off.


    CDRIVE Hauling 10' pipe on a Trek Shift3

    May 8, 2012
    An automatic coffee maker is one thing but unattended cooking is entering a danger zone.
    Are you sure you've thought this through?
  4. neurotictim


    May 15, 2012
    I appreciate your concern, but yes, this is actually quite safe. I've put a considerable amount of thought into designing this to be safe and fun, and short of breaking the bulb and getting a shock, it will be as safe as any other alarm clock. In fact, I'm going to add a tip/tilt breaker that will open the lamp relay (thus turning off the lamp) if the clock isn't perpindicular to the ground.

    As it stands, aside from the delay on relay for the speaker and fan, it's more or less done. Of course, I still need to make the box pretty, but I ran a functional test several times last night after getting the relay wired up and getting everything mounted.

    Took a quick video of it working, before I finished mounting the piece parts.

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