Motion Detector as a limit switch

[HorridHenry]

Instead of using a Micro switch I'm thinking of employing this circuit into the CNC.

Anyone see a problem using an Infared motion detection rather than a mechanical one?

[hgk]

Just curious, why does it need a transmitter instead of just being a switched on ir led?
Regards -George

[HorridHenry]

Its a beam breaker IR ie any solid intrusion between the beam triggers the limit line on the bob.

[bowber]

Quite a few people do use them but you need to guard against swarf and coolant. I think the most reliable way is to have a tag or arm going into a slot in a body that's holding the switch.

You could also try proximity switches.

Steve

[peteach]

The circuit you found is for a motion detector, like for turning on a light in your yard! Fine if you want to know if someone gets near your machine, but will never be a limit switch. Micro switchs are so cheap & simple I wonder why you feel the need to use something more complex.

[cnc4cheap]

Instead of using a Micro switch I'm thinking of employing this circuit into the CNC.

Anyone see a problem using an Infared motion detection rather than a mechanical one?

Henry,

Check this out:

LMDC Catalogue: Servo Components

Scroll down approximately 2/3

OPTO LIMIT SWITCHES

Ron

[Muzammal Baig]

When the transmitter frequency would be close to 40kHz then use a off-the-shelf IR remote receiver IC (found every where in all remote controlled devices).
It is a three terminal device with + - and out terminals

when receiver window faces you then left most pin is +5V mid pin is Gnd and right most pin is Data out which will be +5 when no IR beam and 0V when the beam is detected.

so easy to use.
and so cheap in price.

best of luck

[HorridHenry]

The circuit you found is for a motion detector

The circuit diagram says its that but its an Infared beam sent to a phototransistor and when an object breaks the beam it triggers whatever is connected to pin 7 ie a relay,ect

We have all seen them in art gallerys,banks,museums,it doesn't detect motion as such but merely an obstruction in its straight path.

[HorridHenry]

so easy to use.
and so cheap in price.

Exaclty,all parts can be got from scrap electronic consumer products.

[Al_The_Man]

The circuit diagram says its that but its an Infared beam sent to a phototransistor and when an object breaks the beam it triggers whatever is connected to pin 7 ie a relay,ect

We have all seen them in art gallerys,banks,museums,it doesn't detect motion as such but merely an obstruction in its straight path.

Is there any reason then you are not using an ordinary infra red slot detector?
Al.

[peteach]

Not just the diagram says it's that, but the description says so too, read it again. The diagram is deceiving. It works like radar not a beam breaker. Like Al said, "infra red slot detector" they are beam breakers & cost the same as a micro switch. Or you can get some out of old printers, they used them for paper and/or jam detectors. Lots of info at OPTEK Technology: Optoelectronic and Lighting Solutions

[roughneck266]

Proximity sensor would be a better option if you are dead set against micro switches. Although it would be easy to acquire and infrared set from a garage door, or as above from a printer.