Well, I have gotten a Lego Mindstorm EV3 for the grandkids to learn programming. This is a start that will give them a very good start into this field. I have been playing with it for a few weeks now to make sure I get the hang of it so I can help them when and if they need it.
While I've been tooling around with different bots, (and also some very cool machine builds like one that scans and solves a Rubik's Cube), I have been learning alot. There are two annoying aspects of the EV3: 1) Batteries don't last long enough. 2) There is no backlight. So, I set out to tackle these issues.
There is a rechargable battery pack that is supposed to have longer life; I just haven't buckled down to get that, yet. I opted for a corded solution to help with some other projects I'm working on.
I got two dead AA sacraficial batteries, about 3ft of 20ga electrical bell wire, a scalpel (knife or wire strippers will work), and an EV3 brick.
I sat down and ripped the brick apart, got the display out, and started to figure out what I could put where. I was hoping to get an Indeglo backlight and slide it behind the screen. Nope, that was not going to happen this time around. Double-sided adhesive foam is not known for coming apart. Plus I wasn't going to spend that kind of time on it atm. So, I opted to cut some plastic away on the left side of the screen cradle to make just enough room for two tiny surface mount leds I had laying around. This got interesting; as I was constantly in fear of slipping and scratching the lcd or breaking it entirely. I whittled away at the first notch (for what seamed like eternity). I got it done and the fitment of the led just right. I then started on the other one.
Once I got both leds in place, I soldered the wires needed and left about a six inch tail for both leads. I powered them up to ensure all the joints were good. And Vola! I had light. I reassembled the screen into the housing being careful of the wires and the leds (Hot glue would have been good!).
Now, I was on to find a good point to get power from off the EV3. I poured through schematics and probing the board. I tried the programming usb port, but nope. Not enough power there. I found that the full size usb port has a 5v supply, but I can't get to it to solder to it. The main board also doesn't seam to want to budge (More foam tape?). So, I'm going to install a surface mount transistor to automatically turn the LEDs on and off with the main power.
Stay tuned... I'm not finished yet.
