Power Supply

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  • #557

    Hi, got my Defusable Clock on order, can’t wait to get soldering!

    I’m going to be using mine in Airsoft games (capture the bomb etc) and so will need to power the device by battery. Can you please advise what sort and/or how many cells are required to power the device for at least 2 hours? I have a small aluminium briefcase which can house the device and battery/batteries. Will upload pics once done!

    Many thanks in advance

    #1180
    Michael
    Keymaster

    themanontheinside,

    I think you should power it with 6 D cell batteries. That will provide 9V (6 x 1.5V) and should last a long time. I think C cell batteries would work, too. Let us know what you discover.

    I can’t wait to see what you build. Email pics to info@nootropicdesign.com or michael@nootropicdesign.com, or post here and I’ll add to the gallery.

    When you press the red DET button, you can increase the countdown time by pressing the hour and min buttons before releasing the DET button. I added this feature specifically for the Airsoft community. Countdown can be as high as 99 minutes, 59 seconds.

    #1181

    Wow! Amazing response time. Thanks very much!

    Being able to choose the countdown time was the selling point for me on the device. Most games will only usually last about 30 mins, times that by 2 or 3 games and some time-wasting in between and we’ve got about 2 hours gaming time, so hopefully the 6 D cells you suggest will last at east that.

    I intend to construct two devices to be used with the de-fusable clock. One is a briefcase ‘bomb’ and the other will be the ‘sticks of dynamite’ like in your example. I’m thinking I can house the D Cells where the inner dowel rod would/should go, encased in a plastic tube and surrounded by the remaining 6 rods.

    Will also be looking to add a key mechanism in the future to stop the timer instead of cutting the wires. I don’t know how difficult that would be but it would work great with the briefcase scenario….you know, capture the key then locate the ‘bomb’ and defuse it.

    Anyways, thanks again for the swift response. I’ll let you know how I get on.

    #1191
    woudy
    Member

    i just received my clock and mount
    i work on it (i make modifications on my previous fake bomb)
    but for power supply i have a 12V lead battery (like battery for byke) or 11.1 Li-po
    i can use it for clock ?

    #1192
    Michael
    Keymaster

    Technically, yes, you can use 12V input, but the voltage regulator will get a fairly warm. Give it a try, and if you can still touch the regulator after 10 minutes, then it’s no problem. Otherwise, you can provide 9V with six C or D cell batteries.

    #1194

    Hi Michael

    Got the device and it’s all soldered and working nicely from a 9v DC power supply (plugged into socket at home).

    I opted for C cells instead of D cells as I couldn’t get 6 x D cells to fit in the briefcase I’m putting it all in to, but it doesn’t work. However this could be how I’m connecting the C cell holders.

    I have purchased 1 x 4 C cell holder like this one: http://www.amazon.com/BATTERY-HOLDER-4-X-C-CELL/dp/B001DB6KH2

    and 2 x 1 C cell holder like this one: http://www.amazon.com/BATTERY-HOLDER-1-X-C-CELL/dp/B000LR28AM

    They each have a black and red wire at each end which ultimately get connected to a 9v plug like the one in the attached photo.

    Can you advise me on how this should be wired up so I can conclusively decide whether C cells are sufficient or not. The C cells I am using are Alkaline cells of 1.5v and 7300mAh

    Many thanks in advance!

    #1195
    Michael
    Keymaster

    Are you saying that you are wiring the batteries to the connector in parallel? That won’t give you 9V.

    You need to wire the batteries in series, because you need 6 x 1.5V = 9V. That is, wire the holders so that the batteries are in effect “end to end”.

    Example:

    red wire of 4 cell holder to plug connector red
    black wire of 4 cell holder to red wire of first 1 cell holder
    black wire of first 1 cell holder to red wire of second 1 cell holder
    black wire of second 1 cell holder to plug connector black

    See how all the batteries are now chained together end to end. That’s how you get the voltages to add up to 9V.

    #1196

    You, Sir, are a legend!

    Am now very pleased to confirm that 6 x C cells powers the device with no problems! Going to put the finishing touches to my ‘bomb’ and will post pics and a how to once it’s all done. If not tonight, tomorrow a.m. (GMT)

    Many, many thanks Michael.

    #1200

    Hi Michael,

    Finished! Finally. Here’s some pictures for your gallery:

    #1201

    This one is the innards without the plastic case:

    #1202

    The “C4” is just a thick brown card box I made to cover up the battery housing.

    #1203
    Michael
    Keymaster

    That’s an EPIC build! Very nice. I’ve added this to the gallery
    http://nootropicdesign.com/defusableclock/gallery.html

    I also made the images in the forum posts smaller for easier viewing. Thanks for the great pictures!

    #1204

    Nice one Michael! And sorry about the oversized images! Hope it wasn’t too much of a drama to resize them all.

    I wanted to ask a few things: You may have noticed I had to cut an L-shaped out of the plastic covering, this was due to the fact that the Power Jack and the 10uF capacitor stand taller than the DET button and the LED display. There was a space for me to lay the 100uF capacitor on it’s side. I was thinking if I purchase a second one and do a rebuild, do ‘stubbier’ 10uF capacitors exist? Also, would there have been a problem if I soldered the Power Jack on the underside of the PCB? I also would have liked to solder the 4 LEDs leaving more lead so they too stand taller, but was not foresightful enough to do so. They still look great but it would have been awesome to have the rounded tip of the LEDs protruding just slightly from out of the holes in the casing. Would there be an issue if I do this in a rebuild?

    Just wanted to round of by saying a big thank you for your all help and support. The defusable clock is an awesome and really fun build, I will be recommending it to all of the airsoft teams and clubs we play with and against here in Barcelona. All the best,

    The man on the inside.

    #1205
    andyskibba
    Member

    The replacement Michael sent me works awesome!

    I’m using 2 lantern batteries (6V) each to power mine, and so far so good. The voltage regulator’s not getting warm, and it makes for a nice small little package. here’s a crummy webcam pic:

    btw yes that’s an Electrical Engineering book underneath, but I’m studying for mechanical.

    #1208
    Michael
    Keymaster

    I wanted to ask a few things: You may have noticed I had to cut an L-shaped out of the plastic covering, this was due to the fact that the Power Jack and the 10uF capacitor stand taller than the DET button and the LED display. There was a space for me to lay the 100uF capacitor on it’s side. I was thinking if I purchase a second one and do a rebuild, do ‘stubbier’ 10uF capacitors exist? Also, would there have been a problem if I soldered the Power Jack on the underside of the PCB? I also would have liked to solder the 4 LEDs leaving more lead so they too stand taller, but was not foresightful enough to do so. They still look great but it would have been awesome to have the rounded tip of the LEDs protruding just slightly from out of the holes in the casing. Would there be an issue if I do this in a rebuild?

    Yes, you can certainly make some simple mods that will help you on your next device:
    1) The capacitors near the power jack can be mounted on the bottom of the board, as long as you get the polarity correct.
    2) The power jack can be mounted on the bottom. The 3rd connector on the side has no electrical connection so you can simply clip it off.
    3) You can make the LEDs have long leads – no problem. You could connect long wires to the circuit board and put your LEDs whereever you want. Make sure you get the LED polarity correct.
    4) You could also mount a different button and mount it whereever you like. There are large buttons that are really cool, like this: http://www.sparkfun.com/products/9336. If you get a different button, wire it to the lower left and upper right contacts for the button on the board.
    5) You can also do something with a key switch, but that may require programming changes, so you’d need a programming cable or adapter.

    Hacking is fun!

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