In this project, you'll build an ON-OFF touch switch with two separate touch switches; one for turning the LED on, the other for turning the LED off.
The Circuit
This circuit uses two NAND gates connected as an SR-latch. There are several ICs that have NAND gates, but we’ve used the IC 4011 in the example below. Each touch sensor will just be two uninsulated wires standing close to each other on the breadboard.
Although not shown, the 4011 chip needs to be connected to plus and minus.
Parts List
| Reference | Value |
|---|---|
| Battery | 9V |
| D1 | Light-Emitting Diode (LED) |
| R1 | 100 kΩ |
| R2 | 100 kΩ |
| R3 | 10 kΩ |
| Touch Sensors | 4 bare wires, 2 cm length |
| U1 | CD4011 |
The Layout
You can create a touch sensor using two small pieces of metal, like the clipped of legs of a component.
