Electronics Touch Sensitive switches?

Whats a Piezo Sounder?

 

Well, just about any. If you have too much latent capacitance, it'll throw the sensor off. Also, I don't think the sensing distance is enough to make "a wave of the hand" a reality.

 

Shadowspawn:

A piezo sounder is like a beeper, similar to you system speaker, but Im pretty sure it only can put out one frequency

 

actually, piezo buzzers can put out any number of frequencies depening on the DC voltage... the characteristics of the piezo itself determine the range possible (ie they can't all do .01 Hz to 99 GHz)

 

Piezo buzzers sound crap though.... I used one on my 60 in 1 electronics kit when I was young.

 

So then would CS be your input on this? Or do you HAVE to use the out to a relay?

 

mr. p, the circuit shown is just one possibility.

The two input pins are S1 and S2, the output (active low) is OUT. Think of the output like a GPO, it's jsut a logic level, so turning on your peecee with it (bad idea imo) would take a relay, AFAIK.

If you're planning on a realy, a clamping doide is a must. This output is only good for sinking 5 mA, so you'll probably need a transistor in any application that I can think of.

The datasheet is remarkably helpful.

 

So the CS in that diagram is just something to make a noise in response to you touching the sensor? Therefore, it can be left out of the circuit without and problems.

I want to wire this in place of the eject button on a cdrom...with the drive stealthed completely out of site, you touch a spot on the plexi case and the cdrom ejects.

So, if I check the voltage on the positive side of the existing switch and its in the range the input requires for this circuit, can I just connect the output to the other side of the switch?

 

dude! we could do touch sensative binary calculators! we'd be the greatist nerds ever..oh yeah.

ok. sorry. i'll shut up.

edit: thx linear.

 

If you don't want to deal with scrounging up all the stuff, Ramsey Electronics will sell you a little kit that has 2 touch sensitive circuits for $6.95:



I bought one to use in my Borg Cube LCARS project. <Evil Laughter>

http://www.thewarfields.com/BorgCubePanel.htm

 

Ramsey kits are awesome. How's it working for ya?

 

sweet, just perfect for a project I am working on!

Have you tried using it through glass, or do you actuall have to touch the metal contacts?

 

<evil grin>

If you had to touch a metal plate, you could use a key switch to change between using it as a switch, and being +120v AC (or whatever hot is where you are).

Unauthorized users trying to use your switch would be shocked severely Of course if they leave there finger there for long it could melt down the switch and short 120 into your case

</evil grin>

 

Just got my E11X evaluation kit today and well impressed..

it works through 3mm acrylic a dream (good cos thats what its gonna be used for in my new product..

So MANY thanks to Linear and Cpemma for the inspiration for what will be my best project/product ever!!

 

Seems a great little kit, anyone know of these sorta kits in the UK? i know that maplin do kits alike this, like knightrider lights etc, but haven't seen one of these, any ideas would be appreciated

 

You got it from the USA site? I can't find anything similar at RS or Farnell.

 

Got it from farnell in Uk.. and it comes with a reply card - sent that off and got loadsa smaple chips back - all SMD - but will get used ..

362-6003 is the part number

 

Thanks for the code, I still hate the Farnell Search

For anybody else interested, 3625849 is the code for the QT133-D DIL ic, £2.06 each.

 

I hate the whole site even when ya manage to find something the info is so sparse.. - prefer the catalogue meself..

 

Can you use a 555 chip - i have been told you can I dont know the circuit, but will hopefully be using it in the future so will let you guys know.