this may very well be a stupid question, but is there a way to use galvanic electricity that goes through you body to act like a button... like tuoch a peice of metal and a CD-rom opens... I've seen it on a Stereo once, and think it would be cool for a computer.
You mean touch sensor's ?? A piece of metal and when u touch it , it acts as a momentary switch ?? Get the QT110 chips from Farnell, code is 362-5825 Its a touch sensor IC... Good luck
I asked Zap how one of our light switches downstairs works. The switch is kind of like a really sensitive touch sensor but I know that it doesn't work by touch. It looks just like a rectangle peice of metal which when touched by either your hand or an earthed conductor (ie not a loaf of bread - that won't work) it'll either turn the lights on or off, or dim/brighten them depending on how lon you hold the switch. I can't remember what Zap said as I didn't really understand it but I didn't hear him mention anything about galvanic electricity. I'll try to look for the thread. Here is the thread: link
Well.. I just went to farnell.com .. then clicked my own little flag (belgium) ... They had them there... SO I assume u can get it in the UK aswell ... Enter the QT110, maybe ? I don't really know exactly how it works .. but its something with earthing the little metal plate.. u actually dont really have to touch the metal.. if they are behind a thin piece of plexi .. it will work aswell (lets say 1mm for example) cant explain how.. but it does -miracle- (we need a miracle smilie... dont know how that would look like though) I cant say I have tested it myself... but I'm positieve it will work without the plexi (just by the touch) EDIT: http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=TS1
the only problem is I need it in the US and I lloked at the company who makes them, and apperintly, the toggle on and off, but not momentary... and out of curiosity, is there a way to do it without chips, but with something else???
Most high-gain transistors will give you a crude switch if you touch the base lead, it's like the noise u get when u touch an amplifier input. Set it to drive a switch instead of a speaker.
thanks, everybody, all you ranswers were helpfull. but I'm probably going to go with the transistor though
Yeah there is http://www.aaroncake.net/circuits/touch.htm It's not the same thing .. here u will need 2 little plate's .. and when u touch bouth of them , the switch is activated... (momentary (depends on how big the capacitor is) Good luck
That's very strange. It finds the product now... That circuit Lovah posted the link to works, as I have tried a similar configuration myself.
farnell online search sucks. We get told in uni to look in the catalogue if we're looking for specific stuff such as chips.
Hi all ,I hope people are still reading this thread.. I found a circuit to make a real touch sensor... , here it is used as a alarm... http://www.uoguelph.ca/~antoon/circ/alarm2.htm But it is the same thing ..
yea they work on some kind of capacitance circuit involving you and the ground. somin to do with dear old kirchhoff and his merry laws
362-5825 is the Farnel code for the QT110-D (DIP) and this is the Active Low version. Click here for more information on these chips. How Kirchoffs Current Law Comes Into Play - taken from datasheet Like all capacitance sensors, the QT110 relies on Kirchoff's Current Law (Figure 1-5) to detect the change in capacitance of the electrode. This law as applied to capacitive sensing requires that the sensor's field current must complete a loop, returning back to its source in order for capacitance to be sensed. Although most designers relate to Kirchoff's law with regard to hardwired circuits, it applies equally to capacitive field flows. By implication it requires that the signal ground and the target object must both be coupled together in some manner for a capacitive sensor to operate properly. Note that there is no need to provide actual hardwired ground connections; capacitive coupling to ground (Cx1) is always sufficient, even if the coupling might seem very tenuous. For example, powering the sensor via an isolated transformer will provide ample ground coupling, since there is capacitance between the windings and/or the transformer core, and from the power wiring itself directly to 'local earth'. Even when battery powered, just the physical size of the PCB and the object into which the electronics is embedded will generally be enough to couple a few picofarads back to local earth.
