please help! Need help making electric eye position sensor.

[Pomz23]

I need help to create an electric eye sensor, for a scissor lift table. what i need it to do is. sense when the table is not high enough and activate the motor to turn on and raise the table. I do not know where to find such a sensor, nor do i know what type of sensor i will need. because the table can roll around slightly, it has to be able to read the entire length of the table, not just a small position target. So i will a sensor that can project a laser and read if the reflection is present or not. If not present the table will rise.

 

[rjvh]

Based on your discription a laser sensor is a very expensive way to achieve your goal

its just simply that the table goes to a sertain hight

control the motor with an end switch and make this one adjustible in hight (if that is required) other wise instaled fixed on the hight you want

if you mean something different plaese make a sketch of what you mean

Robert-Jan

 

[Gary B]

I worry about shining lasers in people’s eyes. What about a simple LED through a cylindrical lens and a similar photo receptor. When something shiny (like the whites of the eyes) reflects the light source into the sensor, you stop the table height adjustment.

 

[KMoffett]

"sense when the table is not high enough and activate the motor to turn on and raise the table." What's the "reference" for when the table is not high enough (or too high?)...above the floor?..below a table top?...some other object?

Ken

 

[u4gubbins]

are you sure a limit switch on the scissor would not work?
in most situations I can think of this would be fairly accurate.
you could use a laser with a cylinder lens and a light activated not_switch. you may want a limit switch anyway, in case it passes the reflector.

 

[BrownOut]

what about pointing the light source at the floor and sensing the decrease in intensity at the sensor which is attacked on the table near the source ( reflected light ) It can self-calibrate before each time the table is raised. Not the most accurate way, but very easy to implement.