Thread: Giger counter click sound

Tweet

I am searching for a simple circuit that can be used to make the clicking sound a giger counter would make. (would be good to have a knob to vary the output speed.)
I want to avoid using an audio recorder chip.

Ive searched for simple circuits and keep coming up with schematics to build the full device.

I'm betting you could approximate the sound by generating a bunch of impulse spikes. You could try this out pretty easily by using a 555 circuit or microcontroller to generate a variable-frequency square wave train. Then, by putting a capacitor inline between the output and the speaker, only the transitions from high-to-low or low-to-high would come through. I think this would get the sound you're looking for.

- Hook

I gave this one some thought for a bit...

I don't think you want a 555-based circuit. It could make the clicks, but the wouldn't have the randomness that you expect.

This sounds like a great use of a small, inexpensive microcontroller, like a Picaxe. Here's what I think the project needs to do:

1. Make the correct kind of clicks
2. Vary the clicks using some randomness.
3. Be able to speed up the frequency of clicks using a potentiometer (while still maintaining the randomness).

This way, with the pot turned all the way down and the circuit turned on, you'd hear a typical background clicking. As you turned the pot up, the speed would increase, which simulates bringing the detector closer to the source of radiation. This would work for a manual prop.

You might also want an "automatic" mode, where the sounds would speed up and down on their own. So the program would vary them on their own via random values, if this was just for a background effect (not what the original poster seems to be asking for, but if we're discussing this, why not?)

Joshua, does this do what you're thinking of? I can't put this all together myself but I thought that describing it could help.

This is pretty much what i am looking for and i have a ton of microcontrollers laying around. The only problem comes in my programming skills, im better at the hardware, my skill in programming is still a bit limited.

Which microcontrollers do you have? By any chance, do you have an EFX-Tek Prop-1 or Prop-2?

I dont have a prop 1 or 2 around, i do have 2 parallax sx boards, a BS2 board, and about 200 pic18f4550 and pic18f2550's

Joshua,

I was thinking about this on the way to work, and came up with some ideas for you. This is just a rough sketch, of course, but doing it this way would let you have randomized clicks whose rate would be either automatically changed, or manually. To do this you'd need a microcontroller with....

1 ADC channel
1 Timer/counter capable of generating an interrupt
3 IO pins

The user interface would be...
- One switch for auto/manual control
- One potentiometer for speed control when in manual mode

The basic idea is based on lookup tables. This is where you put a table of values in memory, and retrieve just the one you want at any given time. In this example, you'd have one lookup table for the time between clicks. You would come up with a bunch of randomized delays in a spreadsheet, then copy these into the lookup table in the program. During runtime, after each click, the next delay value is 'looked up'. There are different ways to do this, with pointers or arrays, and depending on the microcontroller you use, you *may* be able to put all these values in program memory instead of eating up RAM.

So, that would let you get some pseudo-random delays between clicks. As for how fast the clicks come (on average), this could be adjusted by using the pot (in manual mode), or by another lookup table (in auto mode)

Anyway... like I said, this is just a really rough sketch to get you going, if you like the idea.

- Hook

Hook,

I know this wasn't aimed at me, but I have to say that this sounds like a great start. It's also the type of project that is simple but potentially useful for a wide variety of people. I like to try to get the code working on several platforms.

From what you want in a microcontroller, we can use a Basic Stamp, Arduino or Picaxe (I don't know enough about regular Pic chips but they could probably be used too.) Because you've outlined this in C, we could do the first testing on Arduino; then port the code to Basic for the Stamp/EFX Prop-1 and the Picaxe.

If you have some time to get this farther, I'm willing to test on Arduino, and then help as we move to the other platforms.

I don't see having the time to develop the code myself, as I'm presently trying to develop and build a Medusa DMX demo display for the MakerFaire. However, I'd be happy to assist, or provide some code review if you or Joshua want to dive into this. Also, I saw a potential 'gotcha' in the code snippet I posted. So, if anyone tries to go that direction, contact me, and I'll explain more, and how to protect against any problem.

It also occurred to me that you could do this with an mp3 player, using one looped track (slow clicks), and another track that would go from the slow clicks, to fast, and then back to slow again. By going between the two tracks, you could get both fast and slower clicks, with a nice transition between. Just a thought...

- Hook

Hmm...we'll still need someone who can code better than I can.

Is that for the Maker Faire in San Mateo?