A simple way to make conductive greeting cards without soldering or using conductive paint.
Tip: A heavy 9B pencil trail is also conductive. ;-)
For my maker friend, Lyle.
Step 1: Materials
Card of your choice and design for front.
1/4" copper foil tape. Less than 18" total will be used for one card.
3V coin cell battery. (What I have on hand that works with the LED.)
3528 SMD LED (I had white, 3.2V 20mA)
Hot glue gun.
Step 2: Prep the Insert for Circuit.
Cut one card in half to use as the circuit base. Place this underneath your card front and figure out where to place your LED. Trim anything off the circuit base card that is hanging out when you close the card. Just a little though. We will use clear tape to seal this shut at the end.
Step 3: Create Traces With Foil Tape.
You've marked the spot for your LED. Start your first foil tape trace from one side of your marked LED spot to about 1/2" from the edge of your card. It can be smaller and save on tape. It's your prerogative!
Once you are stopped near the edge, fold your tape in the exact opposite direction that you need to take your trace and then fold it back over itself in the direction you need the trace.
I prefer to have the negative side to the left and sitting underneath my button cell. The positive runs to the right and has an 1/2" tail that lays on top of the button cell.
*DO NOT CUT THE TAPE!You will have issues if you do not use one continuous strip for the negative and one continuous strip for the positive.
Figure 1: you see I am at the end of the card. I then fold the tape to the right.
Figure 2: you can see I folded the tape back over itself and I am now on the correct path.
Figure 3: smooth over your trace with a clean pencil eraser. That helps removed gunk from your foil and stick it down nice and smooth.
Step 4: Add LED.
Careful, nobody sneeze!
These LED have a tiny difference on one corner and the other three are each the same. There is a slant on the upper left corner of the negative side of this particular SMD LED.
Carefully place your LED on the trace lines. You should have a tiny space about 1/16" left open for your LED. Add a small piece of clear tape to the top of your LED and strategically press it down. Pop the battery on and see if it powers up. If so, dollop hot glue over the taped down LED. This is an absolute MUST! The adhesive will give on your tape and your circuit will not light up without extreme pressure.
Step 5: Add Power & Test.
Now we have allowed the hot glue on the LED to dry. Let's fix the battery into place.
Place your battery in the desired position and very carefully squirt hot glue around it to help keep it in place. Do not place anything in between the top of your battery and the foil flap! We need that connection. It's okay if your hot glue dollops aren't cute, uniform or strategic. We are going to hide all of this inside the card.
Allow the glue around your battery to dry and test again. If you have a consistently solid light, let's go seal the deal!
Step 6: Hide Circuit & Test Finished Front.
Line up the circuit base card you just finished to the underneath of your designed card. Tape around all of the edges with clear tape to seal shut. Close your card and press for instant robot love.
This is a quick tutorial for a project that will be for a short enjoyment period. Please be Earth smart and appropriately dispose of your battery. The LED will likely last longer than the tires on your car but not the battery. If you make a card, please come back and share a photo in the comments!
Thanks for hacking \m/