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Line counting sensor? Answered

I have a group (20) of small robots that need to all end on a certain line in a grid. My question is how can I get each car to count the number of lines it crosses and when it reaches the right number it stops. The problem is I have a budget of $75 dollars to make the guidance for every car. If there was maybe some sort of central controller that would work for each or maybe it is just cheep enough to make a simple set-up for each one. Any comments or questions would be much appreciated.
Thanks in advance,



5 years ago

Is that $75 per car or $75 for all 20 cars ?

How thick and dark are these previously unmentioned lines ?

Ultrasonic guidance was not to your liking them ?


I found ultrasonic was getting a little complicated for the time I have left but I am definitely keeping it in mind if I go to the next level. Its $75 for everything I use and the lines are what surround the circles. Oh and thanks for all the help.

OK now it sets the price per robot at under $4!!

Your task master must admit that is tooo small a value !!!

IF you could arrange to make the ring paint conductive on an insulating surface or 
Insulating paint on a copper sheet ( a PCB board material source sheet ).
Can do ?

Then there is a very simple way to count the lines.

The robots have wheels ?
How many ?

I meant ; Then there is a very low cost way to count the lines. !!!

How thick are these lines now ?

Please ..... It is in your best interest to reply all questions to allow engineering minds to be able to help you

Ok I've talked to the challenge master, and the lines are going to be white masking tape. Also I can get more money if I get a sponsor. (Its to try to simulate creating a real world prototype so it gets kind of silly at times) Sorry about the reply times I'm working on the project right now so I'm kind of busy

If you want background for this question or like infra red sensors my other question might help (im posting on my phone so i cant get it to link) www.instructables.com/answers/How-to-guide-a-vehicles-with-two-infrared-sensors/

This is  a line sensing module fro a Picaxe based robot.

A wheeled robot In the UK can be built with it's basic guidence system for about £8 around a picaxe 08M An L293 H bridge and a couple of cheap geared motors I use to use A CD for the chassis.

You can find all the details here

how you count the lines is down to programming.

There are a hundred methods to locate a robot on a grid - be more specific. What EXACTLY do you have and what EXACTLY do you need to accomplish?