Category Archives: Electronics

Every Police Car needs flashing lights

This weekend didn’t afford me enough time for personal projects, but I did have a few moments to solder connections onto the LED system on the RC police car I’ve been modifying. (I also drilled out the rear window).

Controlling the LEDs is simple: they  all share a positive terminal, bring a cathode to ground and you have light. Controlling the lights via an MSP430 is simple – set the connected pin to be an output, and set the pin low. The LED board has built in resistors, so there’s no need to add them.

There are 8 LEDs, 4 of which are independently controlled:

  1. The two (2) Headlights and two (2) Brake lights
  2. The Blue lightbar
  3. The White lightbar on the left
  4. The White lightbar on the right
  5. The Red lightbar

With the soldering of connectors finished, I hooked them up to the Launchpad and made a quick modification to the Hello World program –  this time  setting 5 pins as outputs, and turning on all the lights except the blue and white lightbar on the left. I toggle the entire lightbar approximately every ~6th of a second.

The specific pins to control each light will definitely change in the future, but seeing blinky lights in the meantime is always fun. I’m happy with my choice of this particular RC car – having 8 LEDs makes it real easy to display status codes and will definitely help with debugging later.

Next up: connect a PING sensor to  a small servo to the roof … once my box of servos arrive.

RC Car no longer under your control.

I’m in the middle of reading MSP430 Microcontroller Basics, which I’d picked up for some insight into the inner workings of the MSP430 line from Texas Instruments (especially the MSP30G2231, one of the controllers included with the Launchpad Emulator board). Unfortunately this coincides with a lot of overnight work at the office, so I’m still making progress (albeit slowly) with the RC Car modification and rebuild.

Patrolling a messy desk.

In the past few weeks, I’ve done a bit of work/learning with a couple of Parallax sensors  – namely the PIR and the PING. I’ve ripped out the stock board and replaced it with a SN754410E Quad half H-bridge, and began cleaning up some of the poor solder joints. More on all of this in a few weeks, but in the meantime let’s tryout my new Toshiba Camileo X30 (sorry about the low light) and Cinelerra, and look at using the MSP430’s TimerA for pulse width modulation:

More in a few weeks…

Java Circuit Simulator

While looking for HackerSpaces in my area, I came across the Philadelphia HackerSpace Hive76. Apparently the group has an Art of Electronics class, and while looking through their wiki – I found an excellent Java applet that gives examples as to how many common circuits work.

Circuit Simulator: That's where my electrons went.

Thanks to Hive76 for linking to this electronics resource. Paul Falstad has done a great job putting this simulator together, I definitely recommend it.

The Great Internet Migratory Box Of Electronics Junk: Excavating a box.

I recently received a Great Internet Migratory Box of Electronics Junk (man is that hard to say in the proper order).

The rules are simple: Sign up for a box (or start your own), dig through it and document (in some form) what you’ve taken  from the box and what you’re doing with it, and ship it off to the next person in line. I feel bad that I’ve been sitting on this box for longer than I should have (normally no more than 7-14 days)… but with work, other projects, a house, and not enough sleep lately, progress has been a bit slow. (My apologies)

Let’s go digging:

I’ve found some use already with large capacitors and solenoids (and my Electronics Learning lab kit)… and a small handful of other parts are going into an upcoming project that I plan on writing up (that’ll happen soon). Adding  a few items to the box, and off to the post-office on Monday to keep this thing in circulation.