Category Archives: TI Launchpad

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…

RadioShack Electronics Learning Lab

Recently I was intrigued by a Hack A Day post regarding a low-cost development platform for their MSP430 line of microcontrollers. I’ve long wanted to toy with an Arduino, but with many other projects currently under my belt, I’ve jut not had the time. When I heard the Launchpad was only $4.30, I figured I might as well pick some up for future use.

To make the shipping worthwhile, I ordered 3 of the boards from DigiKey. Unfortunately they were on back-order, but less than a month later – I got my purchase in the mail:

A couple Texas Instruments MSP430/Launchpads.The 3rd I gave to my brother

Each box contains the Launchpad Development board, USB cable, pin headers, a crystal, and two MSP430 chips. The online wiki contains links to a couple IDEs for use in the Windows world – and Hack A Day has a good writeup on using the msp430-gcc compiler in the Linux world.

Acting like an impatient kid, I put schoolwork and other projects on hold for a couple days to dig into the Launchpad. First mission – the basic “RC Car modification”.

Only modify full sized Police Cars.
To disassemble a real police car, first remove a couple tires.

After mapping out the pins on the H-Bridge of the RC Car, I decided to do something I’ve always wanted to do – buy a Radio Shack Electronics Learning Lab and brush up on what little I know.

The RadioShack Electronics Learning Lab. This circuit is a pacemaker for the human heart (from page 32)

This is something I should have had by the time I was in high-school – if not by 5th grade. The Electronics Learning lab contains 2 lab manuals (one covering Basic Electronics, the other Digital Logic), about 20 ICs, a handful of transistors, numerous resistors and capacitors, and jumper wires (among a few other things). The console itself has numerous built in potentiometers, LEDs, a relay, a transformer, a buzzer, speaker, DPDT switch, and many other components ready to use. Each of the built-in components uses springs to make contact. There’s also a built in breadboard.

The two included lab manuals.

Each lab manual contains background information on each of the various components, as well as example circuits that you can build. Each circuit contains a standard schematic, step-by-step instructions, as well as a checklist to help the user build an error-free circuit. The explanations on how many of the circuits work are lacking – requiring the user to do additional searching and reading to get a full understanding of what’s going on. (But seriously, that’s how it should be: You buy the lab to learn, doing additional reading should be encouraged)

If you look closely, you'll see an acrostic poem.

Which circuits you build and in what order you build them is entirely up to the user. Each manual is structured so that learning is incremental: You learn how resistors work, you learn how capacitors work, you learn many different ways in which resistors and capacitors can work together.

My goal is to work through each book page by page (I’m only just over halfway through manual 1). Each manual is about 96 pages long so this can easily be done in a long weekend (or a few in my case).

I really wish my high-school had offered an electronics class. My limited knowledge had been enough to get me by for basic projects, but the labs I’ve done so far have really bolstered what I know. And at $70, this is a real deal.

Next up: After completing all the labs, go back to the RC Car modifications and explore the possibilities of a TI Launchpad.