For this project, I made a circuit on the lid of my laptop that turns four LEDs on at the motion of opening the laptop, creating a cool light effect. The chain is conductive and closes the circuit when it touches a loop of conductive wire attached to the cover.
Materials:
- Laptop
- 4 LEDs
- 4 1000 Ohm resistors (resistance varies for different LEDs)
- Fabric
- Scissors
- Ruler
- Pencil
- Conductive Tape or Conductive Thread
- Sewing thread
- Needle
- Elastic
- Jewelry Craft Wire (check for conductivity)
- 3V battery
- Pendant or heavy bead
Construction of circuit
Create a parallel circuit with the choice of conductive material on a small square of fabric. Initially, I used fabric tape but it lacked strong connections so I modified the circuit and used conductive thread.
Sew a strip of elastic to the top corner of the square. Make sure it overlaps the conductive material, and sew conductive thread through the underside of the elastic. This serves as a housing for the battery. Allow the conductive thread to hang loose; touching the end to the rest of the circuit should close the circuit the LEDs should light up. Send the loose thread through the other side of the fabric; it should not be visible on the side of the circuit. For reference, I’ll call this thread “Connection A”. The thread at the other end of the circuit will be “Connection B”.
Using the craft wire, curve small lengths into closed “S” shapes. Link them together until you have reached a length that touches both ends of the circuit.
Making the laptop cover
Measure a rectangle of fabric the size of the laptop lid and using sewing thread, attach elastic to corners. This is going to secure the cover to the corners of the laptop screen. The square of fabric with the circuit will be attached to the backside of the cover, underneath it.
You can do the same elastic connection for the top, or use craft wire to create a cool metal detail.
Completing the circuit
The circuit is going to be controlled with motion, so the chain will have to be the last connection to close the circuit. Send the thread “Connection A” through the cover and then attach the conductive chain to it. Repeat this with “Connection B” and attach a small loop of conductive wire to it. I added a pendant to the end of the chain to weigh it down to create tension. The LEDs should light up when the conductive chain touches the loop!