Tuesday, July 27, 2010

Firefighting, Robot Expo, Maker Faire

John Maushammer's Asteroids Watch. 
Home made SMT at its finest! 
My favorite Maker entry by far.

Illness and family matters took priority the last few days. With both resolved, let me tell you about last Saturday's Robot Expo, mini Maker Faire, and Firefighting competition.  The day featured a wide array of great robots, creative gizmos, and cool whatsits.

Firefighting. Perhaps you've been eagerly awaiting resolution of the cliffhanger. Would Pokey succeed in his firefighting duties? When I arrived, the arena was set up, but alas, only two robots were capable of taking to the field in competition. One was fielded by none other than our good pal, Chief Creator of Club Workshop, Stephen Garran.  The other was... my very own robot, Pokey!

It was a fight to the finish, a robotic grapple of epic proportion!  Metallic minions marching forth to do battle with the Candle, and roll home in victory--or defeat!

...except what actually happened is that Pokey didn't have a fan, and Stephen's robot spun around in circles. (sigh)

The fan motor circuit I had just put together was fatally flawed and so I disabled the fan. But I was able to teleoperate Pokey from my laptop and he consistently searched for and pointed at the candle flame when asked. Not very functional, true, but at least we were able to demo the concept of firefighting to the audience... less the excitement of actually putting out a flame. Ah well.

Robot Expo and Maker Faire. Rather than tell you, let me just show you some highlights.

A low budget cellphone robot

First Lego League arena, left; 
David's robotic tank is coming along nicely, right.


Basil is a voice operated robot with impressive object avoidance capability.

A cellphone controlled Mech faces off against a deadly paper target, left. I forgot whose small robot is pictured above right.

George built a Rubik's cube solver from online plans and software. It solved cubes in just a few minutes.

Extremely beefy rover robot with welded steel tube frame, gargantuan motor controller boards (a dozen TO-220 transistors per channel), wires as big around as my fingers, and dents in the frame that I suspect may have been caused by running down a full grown bull moose.

Kurt's robomagellan with laser rangefinder, GPS, and more. 
This beastie was fielded at the Sparkfun Autonomous Vehicle Contest earlier this year.

Underwater ROV using pumps for thrusters

Friday, July 23, 2010

Low Cost MSP430 LaunchPad MCU kit

Hobby robotics just got cheaper for the masses.  Texas Instruments recently announced the LaunchPad, a development board for use with their MSP430 microcontrollers. It costs $4.30.

That's less expensive than just about every other off-the-shelf robot component you can get these days. Almost 1/3 the cost of a single GP2D12 infrared distance sensor, for example.
The LaunchPad includes a development board, 2 programmable MSP430 microcontrollers, mini-USB cable, PCB connectors for expandability, external crystal for increased clock accuracy, and free & downloadable software integrated development environments (IDEs) – everything you need to get started today.
I have two on backorder.

Thursday, July 15, 2010

Firefighting: Another Update

The fan motor driver board (left) was no sooner done, than I detected an obvious malfunction. A solution came while I was failing to go to sleep in bed last night :) Turned out to be a solder bridge. Fixed*.

One of the IR pairs for the encoders isn't working. Replacement boards were out of stock but individual chips were available. More are on order overnight--but Sparkfun doesn't do same day shipping. The trick will be to replace an SMT part without a rework station. Tomorrow night.

I'm most likely re-gearing Pokey to be even slower--even though I said I wouldn't. Why? To gain more precise, low-speed control when aiming at a candle.

Outside of robotics, I was picked as a juror yesterday afternoon for a trial which lasted for us until today at 7:00pm. That and some other life stuff going on.  I'm beat...

Some code needs writing and the fan motor and board needs mounting. Let's see what I have the willpower and energy to get done with the rest of tonight...

* Fixed?? Not so fast hotshot. After posting the above, I discovered that the circuit has a major design flaw. Namely, the MCU cannot turn off the fan. Oops.

Wednesday, July 14, 2010

Firefighting Update

Pokey: Getting Close...

The last few evenings I've been burning the midnight oil. Pokey's camera and vision processor board are mounted to the chassis, encoder discs are installed, and various other details completed.

Only three days left to work on it and there's lots to do.

I had two programs for the main controller. One implemented remote control over bluetooth. The other interfaced with the camera board to point Pokey at a bright light. Fortunately I got this latter pair of programs working again.

If I combine the two I can at least demo Pokey, driving it to a room with a candle, pressing a button, and letting the robot take over from there to find and put out the flame.

Monday, July 12, 2010

Firefighting Announcement and Update

SHARC/FRR Robotics Expo and Mini Maker Faire

Date:Saturday July 17, 2010
Time:11:00 am - 4:00 pm
Location: Club Workshop

Over the last few weeks, the SHARC and FRR roboteers have been working on their robots for the July 17 expo which includes Robot Fire Fighting, Robot Sumo and more.

Pokey, however, is sitting in pieces. {Insert numerous excuses and sob stories here}.

Pokey is a long way from competition

Not much hope of full functionality at this stage but I might be able to get it to detect and extinguish a flame if I just set it down in a room with a candle. The vision / detection system works just fine, albeit at a glacially slow (dare I say "pokey") frame rate. And I was able to code the robot to rotate itself to point to a flame. I'm not giving up entirely. Let's see what I can get done in the next few days. I'll keep you posted.

Friday, July 9, 2010

Spunky the Photopopper

Spunky, the Photopopper, a BEAM robot

Vital Stats
Weight: 19.7g; Size: 7cm length x 7cm width x 4cm height
Fred Solar Engine with 7600uF capacitance
Powered by dual Solarbotics 24x22mm solar cells

File this one under "stuff everyone else has done so I guess I better do it too."  I build this little photopopper several months ago. I'd been wanting to put together a BEAM photopopper for awhile -- I pulled most of the parts together about three years ago (ouch!). It was supposed to be a simple first project to get my feet wet in building robots. Oh well.  Better late than never, I guess.

For the first attempt, I followed Ray Diaz' tutorial for building a FLED (Flashing LED) photopopper using Ben Hitchcock's Fred Photopopper circuit, but with a few minor layout changes. Following my own advice, I prototyped the FLED solar engine on a circuit board and tested it out then built the photopopper you see here.

The power source is a pair of multi-cell 22x24mm Solarbotics solar panels that are replacement for the no-longer-available Panasonic BP-243318.  Motors are pager vibrator motors sourced from one of the online electronic surplus sites. Of the two types I had only this smaller one actually worked.

Removing the crimped weight from the motor shaft was a matter of cutting a slot in the middle of the weight with a rotary tool and using a vise to pinch the two halves together at the slot, which un-pinched the motor shaft.  Works like split shot fishing weights. A pair of 3300uF capacitors store power along with a third 1000uF up front added for balance.

The little bug works... sort of.  It's persnickety about the orientation of motors, weight distribution, side height, amount of indoor light, and so on.  Too much rear weight and it wants to pop a wheelie and fall back on its butt.  Too much front weight and it has trouble dragging the skid around so it just sits there.  Tuning the motor orientation for optimum performance takes patience. Lots and lots of patience

Nevertheless it is strangely fun to tinker with and to watch once it's operating correctly.  I haven't added the obstacle avoidance Solarbotics antennae (spring switches) yet but that should make it all the more interesting.

This photopopper was supposed to be my first robotics project to sort of get my feet wet.  Instead, I dove in head first (or fell in...) building Sparky then Pokey.

Following a naming trend... I'm calling the little guy Spunky.

Saturday, July 3, 2010


Been really busy lately with work (just got back from a week long business trip) and trying to get my Jeep through emissions.  The SHARC gang did take my firefighting arena and started working on it; they're nearly done.  I don't know if I will have a chance to go to wherever the arena is to do testing and coding.  So I may build another simpler arena again here.  Pokey, really, is nowhere close to being ready right now. And there's only two weeks left. Hmm...