Simple sine wave generator - Page 1
Forum section: electronics / beginners

author: rafalpilat0077
author_rank: Contributor
timestamp: January 02, 2014, 11:44:41 pm
content: Hi, i am a beginer and new to this forum.I want to generate a sine wave (or square wave) and connect is to a speaker to make an anoying noise. It would also be good is i could change the frequency using a potentiometer. What would be the simplest way to do that?

author: sleemanj
author_rank: Super Contributor
timestamp: January 02, 2014, 11:48:46 pm
content: Quote from: rafalpilat0077 on January 02, 2014, 11:44:41 pm555 timer.

author: Dave
author_rank: Super Contributor
timestamp: January 02, 2014, 11:50:21 pm
content: A square wave is going to sound way more annoying than a sine. It's all about the higher harmonics.

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 12:40:18 am
content: Isnt the 555 timer limited to a low frequency

author: w2aew
author_rank: Super Contributor
timestamp: January 03, 2014, 12:46:29 am
content: Quote from: rafalpilat0077 on January 03, 2014, 12:40:18 amYes, but audio is low frequency.

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 12:48:31 am
content: About how high could the 555 timer go in frequency?I am looking to make the noise like 4-8khz

author: w2aew
author_rank: Super Contributor
timestamp: January 03, 2014, 12:51:15 am
content: Quote from: rafalpilat0077 on January 03, 2014, 12:48:31 amNo problem. 555s can go well above the audible frequency range.

author: sleemanj
author_rank: Super Contributor
timestamp: January 03, 2014, 12:53:03 am
content: Quote from: rafalpilat0077 on January 03, 2014, 12:48:31 amI think any 555 can handle 100kHz, probably 200kHz, even chinese sourced ones. Some datasheets specify anywhere up to 2MHz as the maximum.

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 12:54:34 am
content: Yes. I tought its a maximum of 100hz becouse i looked at it on digikey. Rechecked it and it apparently is 100Khz not 100hz.Epic fail

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 12:59:43 am
content: Anyways , thanks for the help

author: dentaku
author_rank: Frequent Contributor
timestamp: January 03, 2014, 02:26:33 am
content: The words to search for would be "555 Astable multivibrator"The Wikipedia page for the 555 timer has the schematic for it.http://en.wikipedia.org/wiki/555_timer_ICReplace the 2 resistors with 10K potentiometers and use a small capacitor like 0.1uF or 1uF then turn the potentiometers to change the frequency.There's a ridiculous amount of little things you can make with a 555 or 556 you can buy at Radio Shack.http://www.sentex.ca/~mec1995/gadgets/555/555.html

author: Rick Law
author_rank: Super Contributor
timestamp: January 03, 2014, 02:30:39 am
content: Quote from: rafalpilat0077 on January 02, 2014, 11:44:41 pmSince you are a beginner, and OK with square wave sound, I know this circuit is easy for beginner. I made this one as my first project when I first (return to) play with EE.The attached schematic came from the TI datasheet.

author: zapta
author_rank: Super Contributor
timestamp: January 03, 2014, 03:19:53 am
content: Quote from: rafalpilat0077 on January 02, 2014, 11:44:41 pmIf you have an Android phone, you can use this apphttps://play.google.com/store/apps/details?id=com.tronotech.waveformgeneratorlite&hl=enIt can also do frequency sweeping which is even more annoying.

author: rodcastler
author_rank: Regular Contributor
timestamp: January 03, 2014, 03:34:52 am
content: go for the real deal and google "atari punk console". two 555 or one 556 and you'll end up with a sweet sound generating machine you can build in 30 minutes.

author: noisebox
author_rank: Contributor
timestamp: January 03, 2014, 07:20:29 am
content: Hi, I've just signed up to this forum and I see a topic close to my heart, making a noise through a speaker!!The 555 was the first circuit I learned and once I had that nailed I found myself getting into electronics, I'm still very much a beginner but these are great simple circuits to learn, and fun (and I love noise!)I found the 555 quite limiting though as you won't get a true 50% square wave as the pulse width depends on the ratio of the two resistors across pins 6-7 and 7-8 (I think?!?!) you can end up getting a very nasly thin pulse sound if you are using a variable resistor to adjust one of these....what I discovered was the world of CMOS and the simplest oscillator ever, a true 50% square wave (to my ears anyway) using the 40106 schmitt hex inverter. The beaty of this is you can create six oscillators on one chip (mix them together or use one to modulate another, like a siren sound etc)...all you need is a battery, a 40106, a capacitor and a variable resistor (pot). The output is hot (ie. same as your power source) so you may want to reduce the output with resistors, but the chip can't drive a speaker itself (unlike the 555 which can drive a small speaker) so its best to plug it into some sort of amplifier, of course you can build one as well with an LM386 and a small amount of components (these will kill a battery very quick).Not sure on forum rules for posting links to other sites but if it's ok, here are some links to what I'm on about that should help you.The best bet really is to have a look at Nicolas Collins Hardware Hacking Manual, this has a load of CMOS circuits and good beginner electronic stuff, but the section on "worlds simplest oscillator" (page 64) will be what you are after!!http://www.nicolascollins.com/texts/originalhackingmanual.pdfLM386 schematic for driving a speaker can be found here....this site also has a lot of schematics for building noise boxes using CMOS chips!http://www.beavisaudio.com/library/LM386/LM386.htm

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 10:04:21 am
content: Quote from: Rick Law on January 03, 2014, 02:30:39 am

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 10:05:58 am
content: Quote from: zapta on January 03, 2014, 03:19:53 amHmm...I dont have an android phone. Maby there is similar aps in IOS.Again, this is not suitable for what im doing becouse i want to make it small and cheep. Not use my phone.But thanks for the help

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 10:07:51 am
content: Quote from: rodcastler on January 03, 2014, 03:34:52 amI wanted somethink small and cheep. Not a large project like that. Hovewer thanks for showing me that becouse ill probably make one.

author: rafalpilat0077
author_rank: Contributor
timestamp: January 03, 2014, 10:12:27 am
content: Quote from: noisebox on January 03, 2014, 07:20:29 amThat is a lot of information i will have to consider.I think the 555 timer would be good as a start.Thx for the help

author: dentaku
author_rank: Frequent Contributor
timestamp: January 04, 2014, 04:03:26 am
content: This post inspired me to go looking for more ways of making squarewaves again. Lately I've been messing with a voltage controlled SAW wave oscillator but tonight I had fun messing with square waves again.I decided to finally use those 4000 series CMOS chips I've never used for anything before.The "Clock Pulse Generator" from this site is the simplest square wave generator I've ever built.http://coolcircuit.com/circuit/4049/index.htmlReplace the 100K resistor with a potentiometer and you can vary the frequency.

author: Fabiusp98
author_rank: Contributor
timestamp: January 05, 2014, 02:36:51 pm
content: Another option would be a Schmitt trigger based oscillator, with this you can go up in frequency quite a lot, and it's easy:http://en.wikipedia.org/wiki/Schmitt_triggerhttp://talkingelectronics.com/pay/BEC-2/Page49.html

author: Zero999
author_rank: Super Contributor
timestamp: January 05, 2014, 05:29:33 pm
content: This should be easy to implement with some CMOS gates for an oscillator and an H-bridge IC to make it very loud.

author: dentaku
author_rank: Frequent Contributor
timestamp: January 06, 2014, 02:07:36 am
content: After posting my last message I just happened to find a 74c14 Hex Shmitt Trigger from a dead UPS so I unsoldered it any yes it IS the simplest square wave generator yetI just built 3 oscillators with 3 separate pots out of half a 74C14 and mixed the outputs together. You get all kinds of weird sounds.

author: noisebox
author_rank: Contributor
timestamp: January 06, 2014, 11:51:27 am
content: Mix the outputs together with diodes, things get interesting! You can also cross modulate the osciallators using diodes for some alien noises, or siren sounds if you have one in LFO frequency. Run the output into a 4040 and you can generate sub octaves....There is a particular sound I like when i "starve" the oscillator chip of voltage (ie. putting a pot between the 9v battery and the power pin, as a voltage divider), but I'm not sure, this may be bad for the chips?Replacing the pots with LDR's can produce some great effects, tape an LED to an LDR to create a vactrol, and use one oscillator to blind the LED, use some caps to create a lag and you can create a good siren sound....

author: dentaku
author_rank: Frequent Contributor
timestamp: January 06, 2014, 01:36:54 pm
content: I like the way you thinkThe diode thing was the next step was going to take.Quite a while ago I made my own Vactrol without knowing people actually did that.Now I wish I had a 4040.Quote from: noisebox on January 06, 2014, 11:51:27 am