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How to guide a vehicles with two infrared sensors? Answered

I have a robotics project where I need to guide a few robots to specific circles that are at a random distances. On the day it is due I will be given the distance to the middle of the circle and can adjust what ever guidance system I have. There is a budget cap on the project so i would like to use just one or two controlling things for every robot. Now what I was thinking was to set up some sort of IR beacon in the starting square. If I placed two beacons, one at each corner or the square (each circle is a certain distance from each side of the square) I could have an arduino to remotely control them. I hope that makes sense so if you have any ideas or questions that would welcome both. Thanks in advance,



5 years ago

Are you using stepper motors ?
Are you using a single IR detector ?
Pointed ( looking ) which way ?

What my plan was was to have two beacons in the corners and have the ir transmitter on the vehicle and have the receivers on the beacons to measure the distance. I do not have stepper motors I was just going to cut the power to a geared motor.

Measuring distance by IR intensity even in total dark is very difficult

This is further complicated by the nonlinear IR LED intensity vs angular displacement.

The only way I know to overcome most of  these impediments is to spin he led or reflect it through a rotating mirror.  
This would enable the detector to detect a peak intensity somewhere each led revolution  as distance changed.

Ok thats sounds complicated, do you think just having the vehicle find the most highest concentration will suffice? Or is there something more simple?

My difficult, how do you measure distance from a highest intensity
when the IR beam is not pointed at the photo sensor ?

BTW how is your robot steering work ?

Yea this is getting really hard really fast. What if I had the beacons flash with a different code and got the distance from that somehow? Also my steering is just your standard servo back and forth.

I was hoping you had a solution, I never saw a working IR distance.

There is a mirror grating detector that can provide a semblance of LED distance but must be pin point aimed on target and only inches away..

The only good way I know of. How do proper distance is to use
this ultrasonic sensor.   It sends a sonic sound burst and
measures time of flight from the nearest echo target.
Works with any uP.

You will need two such sensors to triangulate and steer your bot
to the target center.


5 years ago

If I understand this correctly.
  1. You are not permitted to place a beacon in the circle ?
  2. You want to measure distance by IR intensity ?
  • what about two narrow IR slots and
  • determine the intersection by peak intensity


1. No none of my controlling factors can leave the start square
2. If I understand you, I cross the beams (uh-oh) at a certain point and the vehicle detects that strongest point and goes to it?

Thanks for the reply