Need to make a prop of sensitive nature

Need help with a project? Trying to find a component? Post any general technical questions here.
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Joined: Sat Jan 14, 2017 10:57 pm

Need to make a prop of sensitive nature

Post by Billy » Sat Jan 14, 2017 11:29 pm


As this is my first post I'll introduce myself as that should also help calm any fears as I am going to ask for help making a "bomb" (not a real one, relax)

My name really is Billy (William) and aside from serving in the Army since 1997 I also get involved with corporate training days and running Airsoft events. I have a mechanical background (HND. In automotive engineering) but electronics are absolute witchcraft to me.

In an ideal world I know what I want and what I want it to look like, but in reality I have zero clue how to go about building it.... And I'm pretty sure the Saturday boy in Maplins would have a heart attack if I asked for his assistance!

So yes, I am looking to make a bomb. Controversial and not to everybody's taste but is an excellent tool for making people work under pressure on a timed scenario.

I would like it to have the following options, all of which with their own on/off switch so we can vary the use of the build.

- Loud alarm - loudest health and safety would let us use (120db) if it could be really annoying too that would be great.
- Strobe lights - to operate at the same time as the alarm.
- Alphanumeric key pad - one we can change the code on each time it is used to prevent anybody already knowing it.
- Digital display countdown timer - game scenarios vary but typically they are 1hr in duration. Being able to display 3600 seconds on a count down or 59:59 on a count down would be excellent (alarm and strobes to activate at zero)

Now so far all of that (I think) is relatively straight forward with the right knowledge so this is where I want the moon on a stick.... In addition to the above I would like other methods of either activating the strobes and alarm or disabling the timer or doubling the countdown from 1 second to .5 second intervals.

- Mercury tilt switch - either as a tamper device in game or as an additional incumberment for corporate days (balance bars and low level assault courses are used. This is a modern take on a tray of wine glasses)

- wire cutting - female wire grips bridged by different colour wires. They can be pulled out (or cut for the added atmosphere). The correct cable will disable the device. A wrong cable will double the countdown. (I would need to be able to change which does which as regular players would soon become familiar with whips have wire to pull)

If it is at all possible as well I'd like the keypad to double the timer speed if the wrong code is entered.

I appreciate with all the switching options this may not be particularly straight forward, or even possible. When it comes to the build I am stuck in the dark ages. I could physically put it all together and fabricate it all into a James Bond style case but I wouldn't know where to start with keypads, timers, brains, how to program it all.....

So in short, please help!

Thanks in advance.

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Joined: Sat Jan 14, 2017 10:57 pm

Re: Need to make a prop of sensitive nature

Post by Billy » Mon Jan 23, 2017 5:52 pm

Clearly not the most active of forums!

Can anybody recommend a forum with a bit more traffic please?

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Joined: Sun Aug 23, 2015 12:37 pm

Re: Need to make a prop of sensitive nature

Post by Parrotdrone » Mon Jan 23, 2017 10:41 pm


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Re: Need to make a prop of sensitive nature

Post by David » Wed Feb 15, 2017 1:41 pm

I think you are asking a lot here. What you have outlined is a substantial project - not impossible, but one that would consume a large amount of time in the design. If you are looking at something more than a block diagram (i.e. with the types and make of timers, relays, keypads, plugs and sockets, components and so on all specified and available), IMHO, it is unrealistic for any contributors to this forum to be expected to deliver a fully working design where you can just go out and buy everything. Contributors to this forum are not paid, and give of their time freely with pointers in the right direction. Can you take a block diagram and work on from there?

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Joined: Thu Aug 17, 2017 6:37 pm

Re: Need to make a prop of sensitive nature

Post by Kram » Thu Aug 17, 2017 7:33 pm

Hello Billy
I'm not offering to physically help as I'm very busy but a micro controller would sort you out, I'm thinking of a PIC micro they're cheap, they come with various input and output pins and are almost stand alone ie need power, inputs from switches, buttons etc, has is own timer circuit etc etc but need to be programmed but the program can be as clever as you like. The input pins signal the controller and the program takes over, output to the world via the output pins so keypad and siren aren't a problem. I'm not a programmer i only dabble my toes. Lots of free info to be found on the PIC and how to program.

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