Let's Make Robots!

Mapping robot

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Hi Everyone, great site. Just created an account so i thought i'd share my robot with you. I originally designed this robot as a micromouse and i got it to navigate through a maze but decided to try and get it to do other things. I built a robot at university that was able to navigate and, by sending data to a pc, create a primitive map. It wasn't very accurate so im now trying to improve on this with my latest robot. This robot uses modified servos to drive. Theyre modified for continuous rotation and i ripped out the electronics inside and designed my own pcb to replace it, and it now has built in encoders using IR. It has a 3mm stainless steel chassis with aluminium struts to support the control board. Its tough but it weighs quite a lot. It has three sharp IR sensors and the control board uses and Atmel ATMEGA16 or 32, again designed by myself. It also uses a devantech compass and ive just equipped it with an easy radio module.



Update: I originally had my robot equipped with an easy radio transmitter and had built a reciever board to allow my PC to collect data from the robot.  But the Easy radio receiver stopped working, i don't know why but i couldn't get it working.  I had always planned to swap them for trancievers so this seemed like a perfect opportunity.  I have built two new circuits and i can now collect data from my robot and control it from the pc.


Update: My utimate goal with this robot is for it to be able to gather data to create a map and have it displayed graphically on a pc.  To start i want to have a robot mimic on the pc screen showing what the robot is sensing.  Ive started with readings from the compass which the robot is sending to the pc. I have written a program to receive the data and show it on the screen as a compass.  Have a look at the vid!!


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Exiting project! Can you provide some more details on how the map is created?
My original project used the sensors just for navigation and obstacle avoidance, and sent data to the pc of distance travelled, measured by the encoders and direction measured by the compass.  The pc used this to draw a line on the screen showing where the robot had travelled.  Data was also sent from the IR sensors but this wasnt used by the pc software.  Im working on using the sensor data to plot where obstacles and walls are on the screen.
nice project, i am already thinking in add a compass in mine robot
What sharp sensors are those? Do having them angled in like that cause any interference (I think it would not)?
Sharp GP2D12


Welcome, and thanks for sharing :D 

/ Fritsl

The sensors are sharp gp2d12. Ive angled them because the output from the sensors is unreliable under about 5cm. i.e as an object gets closer the voltage starts to go down again instead of up. Angling them means i can follow a wall quite closely without the sensor getting to close to the object. I havent had any interference having them angled like they are.

I made a big mistake when i first mounted the compass module on an older robot, i used metal bolts! Very bad idea, it has to be as far away from anything made of metal as possible!!

How sensitive is the compass - does it react to e.g. nails or screws in floor panels or floor boards?

Hi Ole, 

The compass is not too sensitive.  It says in the data sheet that it should be mounted around 12 inches from any metal objects but ive found that it can be closer than that.  Anything on the floor shouldnt be a problem.  I have found if my robot goes past any metal table legs too closely it affects the compass output.

Nice sketchup-drawing!