Wednesday, May 28, 2008

Learning something new: Robotics

It's time for another personal challenge, Robotics. I've never proclaimed myself to be a mechanical engineer, (or even play one on TV) Generally, if it has gears and mechanics, I tend to run for cover. It's time to stretch out again. I'm going to take a shot a the creation of a HERO 1 replica. The HERO was originally an expensive robot kit produced by Heathkit.
Like the portable Propeller, I set a target budget of $150.00. I'll be using a Propeller Protoboard to control all of the movement, take commands from a keypad, as well as the robot voice. It will be approx 1/4 scale of an actual HERO. I'm waiting for parts, but here's where the budget is right now.

Parallax Protoboard $20.00
Ping Sensor $29.00
2 Continuous Rotation Servos with wheels $34.00
1 Servo $freebie

I expect to be learning about plastic forming. More about that later.

Friday, May 16, 2008

Recycling Electronics with a heat gun

[rant]One of the most distressing things to me about our society is the fact that we buy things expecting to throw them away. I'm talking about typical consumer electronics items; TV's, microwaves, computers, etc. My grandfather owned his television for years. If it broke down, a repairman was called. It would be fixed and put back into use. Thanks to Chinese manufacturing, we buy products, expecting two to three years at most. Rapid technology advances have made the problem worse and it doesn't take a rocket scientist to realize that we've got a real problem with electronics disposal.[/rant]

That "rant" being said, I've found several good ways to be "green" in my electronics hobby, one of which is the Recycling of electronics components from broken/obsolete boards from everyday consumer electronics. Modern manufacturing uses "though-hole" or "surface mount" design, meaning that the parts are placed by robot, then the entire board goes through a solder bath to fix them in place. Heating the backside of the board will cause the reverse effect, parts falling easily into reusable condition.

I came across this article about this about six months ago. The procedure involves heating the board upside-down. Once the solder melts, the parts literally fall out of the board. The author of this article points out that "using a heat gun to de-solder parts is dangerous!" and mentions to make sure to do this in a well ventilated area. He appears to be doing this inside, which raises some concerns about fumes. Solder is around 40% lead, and a quick Wiki search on the effects of lead poisoning is scary. Heating boards like this will cause some dangerous fumes.

My own success with this has two added safety precautions, doing this outside, (sunny, breezy day) and the purchase of a respirator designed specifically to filter (among other things) lead dust and lead fumes. This safety item was an investment, (around $50) but you've got to ask yourself, "how much are your lungs worth?" Between the purchase of the respirator, and the heatgun, I'm up to around $75, and that would have bought a decent box of electronics, but also being in the PC repair business, I wind up with many dead motherboards, modems, video cards, which I have subjected to the process to collect connectors, relays, crystals, caps, and various SMD parts, so it hasn't taken me long to fill my parts cabinet with plenty of pieces for experiments. In fact I've created a website just for purpose of trading parts with others. Anyone need a few 3300uf caps or 14.318mhz crystals... I've got tons of them.

Tuesday, May 13, 2008

Modern Homebrew Computing

As a youngster I read the book Hackers: Heroes of the Computer Revolution, by Steven Levy and have always longed to understand what it was like to be present at the moment of creation of machines like the Apple I, or the KIM. Sadly, being a "next-genner" I was born too late, and too far from places like Silicone Valley. I grew up with machines like the Commodore 64, and the Apple IIe, and certainly experienced the heyday of the 8bit computer, but wish I could have been a fly on the wall when Woz lit up his first microcomputer. The early home machines hold a very special place in my heart, and I have a reasonable collection of Commodore, Atari, Apple, and Sinclair machines stashed around my home and office. I still enjoy the simple days of computing, before spam, spyware, and viruses.

In the last year I've been playing with an incredible new device called the Propeller. The Propeller is an innovative micro controller, which is capable of eight simultaneous operations (8 cpu cores), and operates at speeds between 80-114mhz. With very little coaxing it can communicate with VGA and TV screens, PS2 keyboard/mouse, even save data on a piece of SD media. It has 32 I/O connections which have been interfaced with hundreds of devices. Several games, miniOS, and basic have been written for this chip.

It doesn't take an EE qualification to work with the minimal amount of electronics required to play with the Propeller. In fact, anyone with causal experience with a soldering iron can now realize the joy of building their own microcomputer. The technology has taken many leaps in the last year I've been involved with it, but there is so much more that it can do, and plenty of room for others to become addicted to the experience of seeing a microcomputer, designed with your own hands come to life.