DIY Touch Sensor

Step 3 Input wire

Strip the tip of the wire and embed it into or behind an object or the surface which you want to act as a touch switch. when connected to a conductive metal sheet, or mesh this works really well. When doing multiple switches, it is important to make sure the surfaces are surrounded by ground, so as to protect each distinct touch surface.

You can see how the light turns on and off when my finger touches the wire.

Comments

[altaholic]

is there any way i would be able to make an on/off latch for the output?

[lasermaster3531]

If you connect both pin 3 and pin 4 to ground it will latch. There Is an 'ible somewhere around the site about building a USB powered proximity detecting led lamp. Just search up touch lamp and you should find it.

[altaholic]

great, thanks a lot. i'll check that out.

[MANIAC]

could you wire it so the LED turns on when you touch it??

[alezito_gdl]

Looking at the operating voltages, I assume it uses TTL logical levels (0v for a logical "0"-off, and 2.7v to 5v for a logical "1"-on). So, this circuit is basically giving a logical 1 all the time as long as you are not touching the input wire. The easiest solution, (supposing you are using the direct output, in case you are hooking it To to the MAKE board, all you gotta do is to reprogram) is to add a generic logic inverter, such as the 74LS04, though that would represent a lot of wasted space. You could also build a simple inverter using 2 transistors and some resistors. Input signal for the inverter should be the output from the touch sensor circuit. The +5V would be wired to V+. 2N2222 general purpose NPN transistor should do the trick. Those are cheap and easy to get. Hope this answers your questions!. Image @ http://www.play-hookey.com/digital/experiments/images/ttl_inverter_sch.gif