Timer w/ Noise Signals - Something to hear in the dark... idea for modifying GraLab

Discussion in 'Darkroom Equipment' started by holmburgers, Jan 18, 2012.

  1. holmburgers

    holmburgers Member

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    Ok, so I also use my classic Gralab enlarger timer when I'm developing film, sometimes in open trays, which means several minutes in complete darkness.

    The glow in the dark is great and all, but it just doesn't cut it and I'm finding myself leaving the tray and putting my head 6 inches from the damn thing just to see when my 30 second agitations should commence!

    Grrr...

    I thought, golly gee whillikers, if I had some kind of simple audible signal my troubles would be over. And I don't mean a metronome that beeps on the second, which would drive me all the more bonkers.

    So my question is, has there ever been a count-down timer that accomodates some kind of intermittent signal?

    However, I think I've got a better idea...

    I'd like to attach a dangling bell at the top, right above 12 o'clock, so that when the second hand passes it will ring it. Conversely, on the bottom, I'd like to have some thin piece of metal projecting upwards so that it will be "plucked" as the second hand passes. (kinda like a jaw harp)

    I've attached a piece of Art (note the capital A) to better demonstrate this.

    Whaddya think? :whistling:

    Any good ideas for materials to do this? I can probably throw something together fairly easily, but specifically I'm wondering what a good metal might be for the all important boing, and I need to make sure it doesn't halt the movement of the hand.
     

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  2. Mike Wilde

    Mike Wilde Member

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    I went the electronic route. I was gifted a little timer by the son of a photographer who had died off.
    I would have loved to meet him. He did lots of colur printing at home in the 70's. Tray heater control DIY, Light measuring device, tray temperature electronic thermometer, etc.

    His timer generates a relay closure and a little chirp from a sonalert buzzer every 5, 10, 20, 40, 80 seconds, or a variable number of seconds. I have set the variable setting to thirty seconds and power it from the enlarger socket of the gralab 300. It takes 45seconds to start, which is fine, because I agitate continuosly for the first 15 seconds anyway.

    It is built around a 555 timer IC.
     
  3. holmburgers

    holmburgers Member

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    Interesting mike, thanks for the contribution.

    I'm not so sophisticated when it comes to electronics. I'm more of a "sticks and stones" guy... caveman if you will. :laugh:
     
  4. MattKing

    MattKing Subscriber

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    Tape or digital recorders are great sources for audio timing cycles, and you can add music if you like.

    Kind of boring to record though.
     
  5. Rick A

    Rick A Subscriber

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    I understand some folks use metronomes for developing.
     
  6. bdial

    bdial Subscriber

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    I think it's an interesting idea. Though something that would make a loud enough noise might well interrupt the hands.
    If you wanted to get into a little bit of electronics, you could possibly wire a couple of reed switches to the buzzer circuit so that the hand just brushes the switch and it would give a short little "beep" when switch closes then opens. It would be easier to implement, I think, if you weren't going to use the buzzer for anything else. (I don't ever use the buzzer on mine, much too loud and annoying).

    Another possiblity might be using light, tape an LED throwie to the second hand; http://www.instructables.com/id/LED-Throwies/
     
  7. ic-racer

    ic-racer Member

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    unicolor_timer_10_benson_midtown_7817752.jpg The simple "jingle bell" timer is kind of like that, but it won't keep running after the jingle, though. It looks like it could be easily modified to keep running.
     
  8. polyglot

    polyglot Member

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    I like the bell idea for low-tech.

    If you wanted to get all fancy you could put a reed switch (they close when there's a magnet nearby, mouser at least sells them as small as 7mm) or three at critical places (with blutack!) on the face with a little speck of NdFeB magnet on the timer arm. Relay will be closed for a couple of seconds while the hand is adjacent, and that can be used to turn on a little 5V piezo beeper. And then of course you have a monstrosity of wiring.
     
  9. Rick A

    Rick A Subscriber

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    That jingle bell timer reminded me of a similar one I had years ago. I forget who made it, but it had a way to set bump stops on the face to trip a bell at predetermined times in a sequence. You set the total time by turning the dial, and the trip fingers activated a dinger as they passed. It was explicitly made for film processing.
     
  10. Collas

    Collas Member

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    What about the RH Designs ProcessMaster II? It times down, compensates for temperature fluctuation, it's programable and beeps every 30 seconds.

    http://www.rhdesigns.co.uk/darkroom/html/processmaster.html

    I use it for film processing in the daylight, but the display can be dimmed for use in the dark.

    Nick
     
  11. Neal

    Neal Subscriber

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    Dear holmburgers,

    When developing film in trays (or color prints) I program the interval timer my Timex Ironman watch. Mine is quite old, but the newest models that appear to have the appropriate function are designated Ironman Sleek 150-Lap. I keep it in my pocket because the dial flashes along with beeping when you get to the end of a program interval. There's probably a way to turn this off, but as the watch doubles as my travel alarm I find it handy.

    Neal Wydra
     
  12. jeffreyg

    jeffreyg Subscriber

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    I have an electronic timer that didn't come with an audible feature. I have an electric metronome plugged in to it and can adjust the time of the "clicks" (usually at one second intervals). I can also shut it off as it can drive you crazy while focusing. It really helps when burning or dodging. I got it a number of years ago in a music store.

    http://www.jeffreyglasser.com/
     
  13. Colin Corneau

    Colin Corneau Subscriber

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    I use my iPhone4 with the Massive Development Chart feature - the timer feature is superb, comes with an audible signal and you can even dial down either the brightness of the display or have it in 'red light' for when you're working in the dark.

    I've used it to tray develop 8x10 and 4x5 sheets, as well as all my film.
     
  14. holmburgers

    holmburgers Member

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    There appear to be as many ways to accomplish this as there are photographers! A lot of great ideas.

    The reed switches sound like a really elegant way to go about this, but a bit advanced for my expertise.

    Hey Rick, the timer your desribe with "trip fingers" sounds kind of like what I'm imaging. Can you recall anything more about it?

    I see weird timers at antique stores sometimes that apear to have many "tines" arranged around the circumference... I have an inkling about them, but never looked close enough to say for sure.
     
  15. JOSarff

    JOSarff Member

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    I use an old Omega CT-40. you can program it for the time, and it beeps every thirty seconds, then the last 15 seconds it beeps continiously so you knoe its the end of the cycle. It also has a metronome function for printing. You see them on ebay sometimes.

    Joe
     
  16. polyglot

    polyglot Member

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    You could totally do it. All you need is a reed switch or three, a battery and a 5V buzzer. Put your reed switches in parallel (so that when the magnet goes near any one reed, you get conduction) and put that lot in series with 5V battery (4 AAs in a holder or a plugpack) and the buzzer. The hardest part by far is mounting the reeds to the front of the gralab neatly and you'll have that problem with any ad-hoc method.


    (it's easier than the mains wiring for your UV box!)
     
  17. holmburgers

    holmburgers Member

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    You don't say... ? :smile: