Bridge Apart


Just a small post on a gap cross robot we had to build for a competition at our hackerspace:

I used a PICAXE 08M2 as the brain.  I wanted to use a bigger chip like the 14M2 with a lot of sensors to let the robot detect the edges of the gap and count the number of turns on the winding drum etc. but I realised on this small scale doing everything by timing works just as well.  So the board has a couple of transistors to switch the bridge and drum motors and a H-bridge for the drive motors all controlled by the PICAXE.  The chassis is a Polulo Zumo and I highly reccomend it.  I used a voltage regulator set at 3 V to make sure the motors dont go slower as the batteries went flatter.

"The great divide"

Design and build a robot that can cross a 200 mm gap. (sounds easy)


* Use any technology you see fit (within the rules below)
* Use a button or some form of input to start your robot.


* Your robot may not be bigger than 150 mm cubed (150 * 150 * 150 mm ) at the commencement of the challenge.
* Your robot may not leave anything behind.
* Your robot may not have any wires for power or control, it must be self contained and autonomous.
* You may not use a quadcopter, or flying toy or anything that can hover.


* The field will consist of two blocks 200 * 200 mm placed 200 mm apart.
* Your robot must start 25 mm from all edges.
* Your robot will only be considered as fully crossed when all parts are on the end block.
* If it falls of the edge of either the start block or end block it is a fail.
* There is no time limit to cross the gap.

The only other robot that were in the competition did not work, so I kind of won by default.  I am sure with a bit more noodling the other robot would have worked brilliantly and I might not have won...
Good luck I guess..

The enemy:  It does look awesome!

Here is a (very short) video of my robot:

Or if I might have messed up the embedded video the url:



Submitted by maelh on Sat, 2017-02-18 18:34

Great idea to bring your own bridge with you and cool implementation.

Submitted by Roxanna77 on Sun, 2017-02-19 12:20

Roxanna77's picture

Very nice implimentation! Good luck in the event!


"Propeller Girl"
I tinker, therefore I am.....

Submitted by nschreiber0813 on Tue, 2017-02-28 12:38

nschreiber0813's picture

Dear: Mr. Booo

Cool robot!!! It would be so cool if it was bigger like the size of a car big but I am not asking you to do that because that would be kinda mean but still I wish it was like the size of a car becuase that would be cool. Anyways nice robot!!!

From: Noah

Submitted by jinx on Tue, 2017-04-11 04:56

very cool, congrats on crossing the void and winning 

Last updated: 
18 Feb 2017 - 14:03
Robot type: