Let's Make Robots!

First Robot-Object Avoider

Wanders about avoiding objects

I've been lurking on this site reading and looking and finally got enough good info to create my first robot.


The chassis is made from 1.6mm thick phenolic. Laser cut from a sheet. Alum wheels were from another old project. I narrowed them and fitted an O-ring tire. Entire robot was modeled in SolidWorks 2009.


Picaxe 18X High Power board (CHI-035) supplies the brains. I had to remove (1) MOSFET and add a jumper to control my Sharp vision servo. Also added the screw type terminal blocks.


Front "wheel" is a Pololu Roller Ball. Servo is a Parrallax (Futaba #FP-S148)

Many thanks to Fritsl for making available the program which I tweaked a bit to get this guy running! The mechanical and electrical parts I can do fairly well but I have a *LOT* to learn about programming. This will get me a good start while I play with future additions and maybe the design for my next bot.

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Really cool robot, nice wheels. What did they come from?

Thanks for the comment!

 The wheels started out as a r/c drag car project years ago. They were made on CNC lathe at the machine shop where I work. The r/c club ended before I got the car built. I cut them down for the Bot and used a large rubber O-ring for a tire. They are 2.00" [50mm] in dia., 2.38" [60.3mm] with tire.

 Cool bot. I like the way the body is all tidy. Can you show us video?

nice wheels. they're shiny blinky and clean. Where can we find them?

I have a CHI035A board, 18M2 and a SN754410 all on order (I like the fairly local "SparkFun") but I have a question...

Have you tried to control motor speed yet? I can't see a way of PWMing more than one motor (the B.6 pin on the 18M2 will control one motor, but not both!) I may have to "pull" the h-bridge and put it on a perfboard so I can control the enable pins.

Like I said, I love the bot! Very STRONG, basic look to it that is something mine never look like. :-( I do great with the electronic design, a little less with the programming and I am horrible at the mechanical stuff.

Keep up the great work and let me know if you can control your motor speed, and how???

(BTW, A 18M2 SHOULD drop right in to that board in the future and has a huge amount of new features!)

  You are correct, the 18 series chip will not do PWM on (2) pins. The motors went fairly slow so I did not have to mess with the speed. It needed a little speed control since the motors ran in opposite directions and the rear wheels were turning at slightly different rpm, causing it to run on a curve not straight. I do poorly with programming and had some help with the program. You can use a "pause" command to slow the motors down.

Congratz on your first robot! Now have fun improvising it, like you know, make it do things :)


Are wheels homemade?