$3.50 DIY TV-B-Gone Micro

Step 18 Optional: Add an Indicator LED

Unless you hold up a camera to the front, there is no indication that it is going. Here's a modification to add a visible light LED that blinks between each code to show what it's doing.

Materials:
3mm LED - $0.06
Another 150 ohm resistor - $0.05

First, take your LED and bend the positive lead (not on the flat side) straight out. Keep the negative lead (with a flat side) pointing the same direction and cut it so that it's about 3mm long. Solder this to pin 7 of the microcontroller, with the positive lead facing toward the switch.

(look at picture 2)

Next, cut the positive lead very short. Cut one lead of the resistor very short also, and solder the two together. Bend the other lead of the resistor around to the positive battery terminal, cut it, and solder it into place.

(pictures 3 and 4)

Now when you press the button, the LED will blink between each code. It will also blink 4 times quickly when all the codes have been sent.