Let's Make Robots!


Object Avoidance
quab.bas2.88 KB

Update 3/27: Per request, I've attached the code I used for this guy.


This is my next little object-avoider, made from spare parts from around the house. I actually made this guy a while ago, but I wanted to try to program a fun personality for it. Since that never happened, I'll just post it and move on.

Parts: Since the bot is powered by low-torque pager motors (yes, with pepsi caps for wheels), the body needed to be lightweight. So i made it out of some old CD cases. I accidentally stepped on the plastic partway through the process, so I ended up with lots of little plastic parts. no biggie; now the shell is just made from lots of little parts. The buck-teeth are made from an outlet cover.

This project also used my first robot part ever: my picaxe project board. While creating my own "Start Here F-type" robot, I accidentally soldered the A/B motor ports into oblivion. So as you can see, I bypassed them, and soldered pins directly to the motor driver chip outs. the rest of the chip is plugged into the board.

Code: I haven't had much success with servos, so I wanted to make an object avoider that didn't use one. To avoid getting snagged on the "blind spots"to either side of the sonar sensor, I made it wiggle from side to side as it moves forward. (I noticed that crabs, who can't move their heads, do the same thing). The goal was to make the bumper switches unnecessary. 

Instead of programming "turn left / turn right" subroutines, i made a single "turn" that either went left or right based on a "direction" bit variable. The main loop then includes an "inc direction" line that toggles which way to go. That way I only have to say "go forward for X, then turn" instead of "go forward for x, turn left, go forward for x, turn right".

QUAB also has a speaker that beep-bop-boops one of dozens of little sounds when he encounters objects, in an effort to give him some personality. But there was a lot of background noise in the movie, so you'll have to take my word for it.

The top of the shell is taken from the same scrapped toy that provided my other bot's housing.quab_top.jpg

Looks tough, doesn't it? The treads are extra Tamiya treads from the infamous gearbox.


I vant to avoid your object. blah!


my jimmy-rigged h-bridge (blue wires).


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So I scrapped my Dogbot project in favor of making a small friend for my cat. Essentiall it will be a remake of the quab with a shoe string that gets flicked around for the cat to chase. Just wanted to say thanks for the inspiration! Also, I have found the alpha counter to be an awesome addition, thanks for that idea as well! 

Then they're used for nothing. :) Mood and pitch were left over from a more complicated program that played music and got frustrated if it had to dodge too many things. Those routines were removed. Delta was similar to alpha, but for lower-level loops. Enjoy!

you would change the measure-taking subroutine to have adc instead of pulseout. you'd also want to switch the greater than / less than tests in all the decision-making (for sonar, less = closer).

The alpha counter basically tells it to run through the main loop x number of times before switching directions and "wiggling". then it resets and starts over again. Basically you can use it as an internal timer to say "when alpha is X, do Y". Calculon doesn't know if other bot-makers use the alpha count idea, but they're calculon's bread and butter.

awesome thanks!!! JUst one more question, calculon. What are the symbols delta, mood and pitch used for? I dont see them anywhere in the rest of the programming. 

hey man, Im failry new to picaxe and was looking over your code here.... why do you need a counter? (i.e. "Alpha") 

also, if I used a Sharp sensor instead, would I use "readadc" instead of "pulseout/ in"?

I really like the look of this little dude, gonna start saving my bottle tops ! Nice work.

Very nice crab-like aesthetic! Sometimes I'm into clean designed-looking robots, other times the Junkbot style suits me - in any case - it is the building that matters!


Nice video BTW. Looks like Quab is pretty good at avoiding obstacles. Looks to me like Quab has lots of personality!!




raw aestethic


this bot is what i LIKE



-i have rated it 5 star..... why i can not see the stars over my post?


I'm new to Robots and I wanted to ask if you could send me the code for that robot?

I think this robot would be a good starter-robot.

Thank you.