1.555.555.555 eric@invisiblefocus.com
Month: December 2017

Preparing for the next rebuild

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Over the last year I have added quite a few extra components to Eric and had run out of places to plug in more I2C based sensors.  Wiring had been cobbled together using what I had to hand and the wires to the sensors on the pan and tilt head her pulling against the servos and giving bad positions as the head was not where the robot thought it was.


Plotting the objects on the map

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My first mistake was to try working in degrees.  It made sense when I started as I could see what was going on but as the mathematics get more complicated I need to be working in radians.  Now is the time to ensure that all the internal variables are in radians and they only become degrees for display purposes. Read More

Teaching Eric to stop banging his head off the waste paper bin.

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The main problem with IR sensors is their dislike of dark or non reflective surfaces, such as a waste paper bin or computer monitor.  Using these sensors we can only work in a controlled environment with white surfaces for walls and floors.  If Eric is to explore we can not be expected to run ahead of him painting the walls white.  I’t time to get out the laser! Read More

FreeMat is now my friend

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When ever I looked at robot control systems I came across SLAM and associated with that were MatLab and Octave and if you are reading this I expect you have found the same.  SLAM stands for “Simultaneous Location And Mapping” (I think) and Matlab and Octave are maths programs.  The problem I had with the explanations were that the ideology was to send the live data from the robot to the maths program, evaluate the data in the maths program, then send any changes to the robot based on the output of the maths program.  That’s cool but I don’t want to have a second computer involved so I largely ignored  this method until I had to get into some serious graphing of data.

I’m not using real time data but I do want to analyse the data from a run (Like reading an aircraft black box after the disaster) and LibraOffice Calc was getting far too slow when It came to graphing the data

Why chose C

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As choices go C++ seemed to me the best option as I already know how to compile a program.

It does not matter what you use to program your robot as long as you are comfortable with the language.

Slightly Miffed Eric – Fuzzy Road.

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On my fathers bookcase was a copy of “Build Your Own Working Robot” by David L. Heiserman (ISBN 0-7042-0171-2). The author takes you through building a robot based on a child’s ride on electric car giving all the circuit diagrams and build instructions. The final, autonomous robot can run around avoiding obstacles and even recharge its own batteries by returning to a recharging station when it needs to. Published in 1976, pre-dating the first home computer, it is all down to logic circuits and some very clever thinking. As a child, this book started me on the road to robotics. I never did get an electric car to work with but I did have access to lots of Meccano. When I left home and ventured into the big wide world my father gave me the book and started replacing the damaged skirting boards. Read More