# Plans / tutorial for sound effect generator using only analog components?

I've been wanting to make a laser gun sound effect attachment for my son's bike. Currently, I'm using the electronics salvaged from his old laser gun toys. All of them seem to use electronics hidden under a black blob of resin or epoxy, which I assume is an ASIC?

I'd love to be able to make this more cheaply, and was wondering if there's any resource out there to show how to make something like this with analog components. I have an old fart machine that seems to use a combination of resistors, capacitors, and inductors to generate multiple sounds (i.e. no microcontroller), so I figure that it must be possible.

I only need one sound, but it would be great to be able to select from multiple, or somehow use a microcontroller + DAC to do it, although the latter would increase the price.

EDIT -- something like this, but cheaper than $10 would be nice EDIT -- also found this schematic but it needs an IC called the HT2884 • What kinds of sounds do you want to make? Simple tones are fairly easy, complex tones (Like I imagine a laser gun sound effect to sound like) slightly more difficult, but speech or music will be next to impossible. Can you provide a link to a laser gun sound? – Kevin Vermeer Jan 12 '11 at 15:23 • Also, do you have access to function generators? That would make prototyping this much easier. – Kevin Vermeer Jan 12 '11 at 15:24 • I believe my Saelig USB scope has a function generator, but then I only have one. I'll look into it. I'll see if I can find a laser gun sound, but pretty much "Star Wars Clone Trooper" sums it up. :) – Dave Jan 12 '11 at 15:27 • The MK113 sound generator seems easier to get than the HT2884: store.qkits.com/moreinfo.cfm/MK113 maplin.co.uk/module.aspx?moduleno=25238 – Linker3000 Jan 13 '11 at 0:41 • @Linker3000 thanks for the link! That looks like an option. Pretty freakin' huge, but perhaps I can shrink it all down if I can get the IC separately. promising! – Dave Jan 13 '11 at 2:14 ## 3 Answers Back when I were a lad, the SN76477 sound effects generator ruled supreme. If you fancy a bit of nostalgia they can be had for just over$9. Admittedly, you need a few other components but they can make a ton and a half of sounds.

http://www.bgmicro.com/ICS76477.aspx

Edit: Just as an afterthought, one of the more irritating circuits that the lads in the electronics club at school used to make up was a 555 oscillator where the timing resistor from Pin 7 to Vcc was replaced by 10 variable resistors with diodes (or LEDs) in series, hooked to the outputs of a 4017 decade counter, which was clocked by another 555 timer. By adjusting the variable resistors and the frequency of the 555 clocking the 4017 you could generate a string of 10 notes in a loop. When this ran at a fast clock speed you got some weird noises.

• thanks for the tip, I'll consider it as I go through my options! – Dave Jan 12 '11 at 18:25
• Do check out the TI data sheet (via Wikipedia) - there's a number of example circuits. Ooh, it took me back looking at all that. I think I have one of the chips still - somewhere! – Linker3000 Jan 12 '11 at 19:48
• I picked up some similar chips for a great price! I think this will totally work. Thanks for the suggestion! – Dave Apr 12 '11 at 6:24
• The circuit you are describing (atari punk console sequenced by 555 and 4017) is a baby10 or baby8 sequencer. – Jeff Wurz Jan 22 '19 at 18:26

it is not analog, but

• you can use R-2R Resistor ladder (acting as a simple DAC) on the outputs of a controller

• or you can create a chain of counters addressing an E/EPROM in a loop, on Memory outputs again R-2R ladder. You can usee 2, 3 or more of the MSB address lines with switch to choose different sound

• DDS is a standard method of generating various tones. The dsPIC series is suitable for this method with a built-in DAC. Two DDS examples here. – tyblu Jan 12 '11 at 19:07
• @tyblu thanks! I'll check it out. dsPICs are pretty cost effective. – Dave Jan 12 '11 at 20:31

I think some of the answers for the question you've linked to give you some good ideas about how to do this.

PWM is a simple way to create a DAC, and you just need to program your microcontroller to output different frequencies until you find something that sounds like what your looking for.

You could use some sound wave editing software like Adobe Audition that has a wave generator that you can use to easily play around with different frequencies and immediately hear what they sound like. When you find something that sounds good, you can then try to write an algorithm to match it in code on your microcontroller.

If you want to just use discrete components, then maybe you could build two Multivibrator circuits with different frequencies, and combine the outputs using an Op Amp circuit to drive a speaker.

• except that I would really prefer a method for doing this with analog components. Perhaps my question should be retitled to ask for a tutorial, rather than open-source, which implies code to some extent. – Dave Jan 12 '11 at 14:53
• @Dave: ok, I've added an option using analog components... – BG100 Jan 12 '11 at 15:23
• @BG100 what are my options for getting the frequencies? Do I need to find a sample and then do an FFT or something (I have never done one before) on the sound to figure out what the composition of the sound is? Any tips? – Dave Jan 12 '11 at 15:25
• I think the easiest thing to do is build your circuit using potentiometers instead of resistors, so that you can easily adjust the frequencies of your circuit... and then you can play around with it and see if you can get something that sounds good. – BG100 Jan 12 '11 at 15:30
• When I was younger I had one of these: quasarelectronics.com/maxitronix/… and the manual that came with it had some great schematics of circuits that created sound effects with analog components... I can't find a copy of the manual on google though... if you can then it might be worth a look! – BG100 Jan 12 '11 at 15:37