Today I finished modifying the doorbell with which I started yesterday. I drilled a 4.5 mm hole through the back of the doorbell and led a solid core CAT5 cable through that hole. This cable will be used to connect the doorbell switch and the 2 LEDs (a white and blue one) to the Jeenode that will be placed in the fuse box which is only 2 meters away. The legs of the LED were bent sideways right there where they come out of the LED housing and these legs were temporarily glued to the doorbell housing to secure the position of the LED for easy soldering. You can still see some residue of the glue (the white blur on the housing surface) where the legs of the right LED touch the doorbell housing.
To get a good insulation from the outside world, I pushed the cable through the hole, put hot glue on it and pulled the cable back a few millimeters; this should suffice for proper insulation. After the wires were cut to the right length and soldered to the legs of the LEDs, it was time to check if everything was working. So I put the 2 halves of the doorbell housing on each other, pressed them firmly, and put the other side of the wire on a breadboard. With a 5V power supply, two 330 Ω resistors and a multimeter I convinced myself that everything was OK.
BTW, it’s a good thing I didn’t choose red as one of the colors for the LEDs; otherwise, a visitor might think he’s being held at gunpoint by a sniper with laser sight 🙂 In other words, the LEDs are a bit too bright, so I think I’ll use a higher resistor value in the final version – that’s why I left the resistors out of the housing in the first place, cause I was anticipating “tuning” issues like this.
Well, now that I have verified that the doorbell is working OK, I can move on to the next step: the JeeNode, some more hardware and the software that goes with it!