HOW TO MAKE CAPACITIVE TOUCH OPERATED TONE GENERATION WITH A MICROCONTROLLER? - Page 1
Forum section: electronics / general

author: nishy555
author_rank: Newbie
timestamp: June 04, 2015, 07:50:07 am
content: Hello… Im a mechanical engineer & product designer from india.....Im trying to make a project....for that I need TO produce continuous tone at 6 different frequencies (between 17000hz to20000hz) or (between 20000hz to 26000hz) from single sounder/buzzer. And these 6 frequencies should be operated with 6 capacitive touch points. When ever I touch one of these buttons specific frequency should produce….Can anybody please clear my doubts….1) Is using microcontroller is my best choice? (Presently im using 555 timers in astable mode to produce specific frequency with 6 Toggle switches.2) Is it possible to produce a continuous tone at specific frequency with line of code using microcontroller? Im working around 20k frequency….Most of the micro controllers working speed is several Megahertz does this produce tone brakes or any other problem?3) How many pins & bits microcontroller im going to need?4) What is the smallest & least power consuming microcontroller I can use?

author: matseng
author_rank: Frequent Contributor
timestamp: June 04, 2015, 08:04:09 am
content: If you can't write software for microcontrollers (code in C) or don't know anyone that does my guess is that a microcontroller is not your best option.For touch operation of your existing 555-circuit you might want to use something like this.

author: matseng
author_rank: Frequent Contributor
timestamp: June 04, 2015, 08:27:01 am
content: But if you want to use a microcontroller a 8-pin ATtiny13 (or similar device) would most likely be enough.One tone output pinThree+two pins for capacitive sensing of six buttons configured in a 2x3 matrixTwo pins for powerRunning at 1MHz it only uses 190 uA.In addition to the microcontroller you need a transistor to up the speaker volume a bit, and some caps+resistors.

author: nishy555
author_rank: Newbie
timestamp: June 04, 2015, 08:54:36 am
content: Quote from: matseng on June 04, 2015, 08:04:09 amThanks for your reply....For now im using 555 timer with 6 resistors along with 6 toggle switches.... When ever switch is pressed that particular resistor comes into circuit and produces specific frequency depending upon resistance value. I dont know how can i add transistor based touch switch at the place of normal toggle switches.....(Im afraid small flow of current that exist through transistor may produce noise/unwanted frequencies while it is unused) ....

author: Moondeck
author_rank: Regular Contributor
timestamp: June 04, 2015, 05:47:56 pm
content: Use one of those capacitive switch ICs from Microchip, they are dirt cheap and have simple "boolean" interfacehttp://www.microchip.com/wwwproducts/Devices.aspx?product=MTCH108Microchip is love, Microchip is life

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: June 04, 2015, 07:16:16 pm
content: Have a look at this guyJulian Iletthttps://www.youtube.com/user/julius256/videosHe's recently been playing with touch sensors and sound generation, one of his recent projects is a "Penny Organ"

author: nishy555
author_rank: Newbie
timestamp: June 10, 2015, 05:48:46 am
content: Quote from: Moondeck on June 04, 2015, 05:47:56 pmThanks a lot for your help.... basically im a product designer(http://www.nishanth.me/home.html) i hardly know about electronics...... Can you imagine how much time it will take to make this for a beginner?? Can i find any related tutorials? or any related projects on web? or it is it better to go for a freelancer? How much should i offer for a freelancer?(I really don't know how hard is this thing to make) i wnat to make this within a month....Please suggest me anything help full....

author: slateraptor
author_rank: Frequent Contributor
timestamp: June 10, 2015, 07:07:43 am
content: I'm curious how you intend to validate implementation considering 17kHz is pragmatic threshold of human hearing for all but a certainly small percentage of the population, let alone 26kHz...food for thought.However way you decide, recommend verifying that the selected sounder/buzzer's frequency response is within range.

author: Moondeck
author_rank: Regular Contributor
timestamp: June 11, 2015, 01:52:43 pm
content: Quote from: nishy555 on June 10, 2015, 05:48:46 amFirst of all, what do you want to make?Second, on your site you say you are an engineer?