#pbasic

Arsonbot has awoken from his slumber. 

But wow, this design needs some work.  The drivetrain is awful, the wiring is crap, I don’t understand anything about the servo or H-bridge control routines...  Maybe it’s time I upgraded this little guy to an arduino platform.

Have fun with your 25 bytes of RAM.  You heard me.

Arsonbot can move again.  So that’s progress. 

I’m reading through the Hero Jr. BASIC manual right now, and I’m finding it to be suitably powerful to handle a great many tasks.  It’s an integer BASIC, with no support for floating point but for a robot, that seems just fine.  It has no graphical needs, so why bother?  Wintek BASIC looks like it will be plenty capable and fun.

One thing I’m glad it includes are GOSUBs, which I happen to like.  I listened to  years of GOTO bashing, followed by folks making fun of BASIC because it had to rely on the GOTO statement for subroutines.  Then I discovered that the GOSUB command existed, and while it doesn’t carry along function variables, or return values, it is plenty powerful.  After that, BASIC became far more user friendly in my mind.  For imperative programming, one can survive surprisingly well without the luxury of modern function system.

I attempted to get Arsonbot’s fireball cannon to work tonight. 

The critical part of the fireball cannon is a glow plug designed for small RC vehicle engines.  My last approach involved a separate AA battery, and a relay controlled by the BASIC Stamp, which did not work.  The relay drew too much power for the microcontroller to successfully actuate it.

Meet Arsonbot. 

He just returned home after spending two years buried in boxes in my storage unit.  I figured it was time to bring him home and commence repair work.

Arsonbot is a scratch-built robot I made during college, but never did finish.  His chassis is based on a Tamiya tank tread kit.  The computing power is provided by a BASIC Stamp 2: HomeWork microcontroller, connected to a Pololu H-bridge module for driving the motors.  There is a Parallax PING sensor for measuring distance, attached to a small servo to allow for looking left and right.  The only other sensor in board is a simple bumper to detect collisions.  The rest of the chassis is composed of assorted Erector Set/Meccano parts and some plywood, plus an antenna for decoration.  Oh and on top sits a small fireball cannon.

The part I never finished in the hardware was hooking the fireball cannon to the microcontroller.  It’s based on something I saw in Make: Magazine years ago, designed to launch flash paper/flash cotton by way of a glo-plug (one from a Nitromethane powered radio control car).  The idea is that the fireballs it launches leave no smoke or ash, and disintegrate within a second of leaving the barrel.  Relatively safe, considering its name.

Now that he’s out of storage, I can redesign the electrical system so I don’t have to rely on three separate battery packs.  In general, operational time has been rather limited due to the power consumption of the motors.  Plus, he can’t drive in a straight line; there’s a bit of listing from the tracks being slightly mismatched and the spokes add a significant amount of friction to the entire drive-train.

He’s programmed in PBASIC over a real RS232 serial connection.  Can’t say I ever wrote a good AI for him, just a few test programs for the critical functions as I added each new component.