For my original Coffee Over IP project, I pulled a network jack off of something and glued it to my coffee mug. Not a serious project, just something silly to do, and it got people to take a second look. The only image I have is dated 2008, so that’s how long ago it was. Eventually, the heating and cooling of the mug loosened the glue and it fell off.
Naturally, the next step is to make it light up. I found it’s a lot easier to just buy some RJ-45 jacks than to pull one off a board and keep the pins intact. Originally, I had intended the transmit light to blink, but the idea I had for that turned out not to work. So, I just made both lights stay on and I’ll save that for COIP 3.0.
I used a CR2032 battery case with an on/off switch for power. The case holds two batteries, but since I only need three volts, I only put one battery in it. I tried to use Velcro to attach everything to my mug, but that caused enough problems that I just glued it all. The good part of this is I can flick the on/off switch with my thumb while I’m holding the mug.
While shortening the wires to make the circuit more compact, the connections on the ballast resistors broke, so I had to redo the whole RJ-45 jack from scratch. I dabbed on some liquid tape to stiffen the connections and make it more water tight. Everything should hold now until I drop my mug.