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Introduction to Robotics – an exercise in thinking

November 6, 2014 by Robin Englebright   

A long time ago in a galaxy far far away I used to get paid for designing robots. I had a hand in designing Mr Psyches, Growler and Cassisus Chrome for Robotwars, worked on the look and feel of the Destructoids for the tv series “Mechanoids”, and made a comic to pitch the idea for an ITV series called Rescue Robots.

Cassius Chrome

With my then youthful children I was also a competitor in RW S5,6 and 7 with our Robot Killer Carrot.

Today I got the chance to revisit the area of Robot Design when I taught a class of 17 University of Brighton D&T and Computing teacher trainees about elementary robotics.
We aimed to cover some of the key areas in the National Curriculum for D&T and computing, and managed to hit most … with more or less success.


KS3 Technical Knowledge -understand and use the properties of materials and the performance of structural elements to achieve functioning solutions -understand how more advanced mechanical systems used in their products enable changes in movement and force

-understand how more advanced electrical and electronic systems can be powered and used in their products [for example, circuits with heat, light, sound and movement as inputs and outputs] -apply computing and use electronics to embed intelligence in products that respond to inputs [for example, sensors], and control outputs [for example, actuators], using programmable components [for example, microcontrollers].


We started by discussing inputs, logic and outputs – looked at discrete components – reed switches, thermsistors, LDRs, LEDs, Is LEDs, and thought about how various systems might work by creating top trumps cards detailing:
logic, inputs, outputs, cost, reliability, speed
for – a garage door opener, a plant waterer,a burglar alarm, a cat feeder, a lunar lander and a mars orbiter… and discovered that whilst there may be differences in costs and reliability, the inputs and outputs and logic are pretty similar for each of these setups.
As a group we then looked at a simple PICAXE BOT120  running a line follower program, and drew a flowchart for the processes and worked how they mapped to the actual code.

'## Adapted from the Bot120 manual by: Willem van Heerden ##
'## bugfixes and alterations by Rob Englebright##
'## initial sensor calibration setup white = 10 black tape = 67
Init: 'Initiation Label
 Symbol Left_Bumper = pinC.1 'Left Bumper Input Pin
 Symbol Right_Bumper = pinC.3 'Right Bumper Input Pin
 Symbol Line_Tracker = 8 'Line Tracker Input Pin
 Symbol Mid_Level = 30 'Custom Calibrated
 Symbol Track_Value = b0 'Line Tracker reading

 If Left_Bumper=1 or Right_Bumper=1 then 'If it bumps then...
 halt A 'Stop Motor A
 halt B 'Stop Motor B
 readadc Line_Tracker, Track_Value 'Read Value
 If Track_Value > Mid_Level Then 'Evaluate Reading 
 Forward A 'Run Motor A forward
 Halt B 'Stop Motor B
 Halt A 'Stop Motor A
 Forward B 'Run Motor B forward
 End If
 End If

 Goto Main

We then tried to run the flowchart application, and the fancy logicator and everything went horribly wrong.

So we switched to the ever reliable LEGO NXT,  and started looking at how we could decompose a problem – in this case the rules for SUMO ROBOTS – and build functional SUMO bots.

 “Lego Sumo unlimited height, 15.0 cm width, 15.0 cm length,  1,000 g weight.

Any method of control may be used, as long as it is fully contained within the robot and recieves no external signals or directions (human, machine, or otherwise). Autonomous robot operation must begin automatically no less than five seconds after being started by the user. Robots starting before the five second mark forfeit that Yuhkoh point.

We had four working NXT units (mine died gracefully after demonstrating the variation on the line follower code) so the students worked in groups of about 4 to analyse the challenge, design a strategy – draw a flowchart and then write the code… or drag and drop the icons in the Mindstorms application.

I gave the teams a starter code based on the line follower code, but switching the “dark detector” for a “light detector” to match the black Sumo ring arena and it’s white boundary line.


Screen Shot 2014-11-06 at 19.34.55

….and the teams went at it, looping through the code, testing and re-testing adding “hair” and labels and extending their weapons with taped on pens.

The debugging of code was frantic, and the pressure grew as we approached the contest.
We ran 2 heats, a final and 3 rd place heat which resulted in real excitement and shouting and cheering… a fitting end to the day.


 Learning technology isn’t just VLE’s and commercial software, sometimes it’s a cute little robot.

If you are interested in using microelectronics in your teaching there are plenty of places that can help… At UoB contact me… elsewhere:

STEM ambassadors – Based at UoB –
First Lego League- International –
(FIRST (For Inspiration and Recognition of Science and Technology).)
CodeClub (9-11-
CoderDojo (7-17
NodeBots- Javascipt for robots

and don’t forget you local Hackspace… I can of course reccomend BuildBrighton … but there are others all across the UK… and indeed the world:

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  1. Jonny says:

    Hi there, do you have any surviving material on Rescue Robots?

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