Clear boartd sensor

[STEAM]

I know that this has been discussed at length here in the forum. However I have been having this error today and found a "workaround" that seems to work fine.
Simply put what I did was: First make sure that the sensor was reading correctly which it was. A reading around 156 with my hand or a piece of wood. Then I took a piece of fine sandpaper and lightly marred the finish of both the glide plate and the squaring plate. I only did about an inch on each plate right below where the sensor crosses them. This makes the plates less reflective. That way when the infrared signal hits these areas it will not bounce back as much of a signal. But when it passes over the board edge the signal will rise greatly and the computer can then detect the board edge better. I think that if the plates (in this crossover area) were painted a flat black( at the factory) it would greatly improve the accuracy of the sensor.
I work in industrial electronics and with infrared sensors quite often.

In no way am I suggesting you should paint these areas yourself. If you don't know what you are doing you could severely damage your machine.

[Jeff_Birt]

Interesting idea...Out of curiosity what board thickness were you having trouble with that prompted you to try this?

[STEAM]

3/4 inch red oak

[Jeff_Birt]

I was curious if you were cutting thinner stock which can cause problems for the board sensor. As you found out it looks for the difference between the amount of reflection on the board and off the board rather than an absolute value. In your case it seems like you sensor is very sensitive and there was not a significant difference in sensor readings on and off the board. Your idea to scuff up the paint is clever, good show!

[STEAM]

I'll have to try different thicknesses and types of wood to see how it fares. I'll post my results later.

[dhauptman]

I am having the same problem but when I put my hand under the sensor or another piece of wood, the sensor reading is between 0 and 7. Does that mean my sensor is bad? Anything else I can try?

Thanks,
David

[Digitalwoodshop]

Yes, this is an interesting concept....

AL

[oldjoe]

David I just replaced my board sensor for the same reason I could not get it to go past 15. So I called LHR and they sent me a new one. I just put it in and have to check what my readings are and call them back. I am assuming you have taken it out and blown it out and wiped it off then retested it.

[dhauptman]

I haven't taken it out yet. I wasn't sure I could. Is it pretty easy to remove?

[STEAM]

I am having the same problem but when I put my hand under the sensor or another piece of wood, the sensor reading is between 0 and 7. Does that mean my sensor is bad? Anything else I can try?

Thanks,
David

Most likely it is either dirty, or bad. An infrared sensor should last the life of your machine. If you have thoroughly cleaned the sensor, try using a mirror. If you still get a low reading then most likely it is bad. However, that is not a call for me to make. That will be up to the techs at LHR. I am in no way affiliated with LHR.

I would be willing to bet that the receiver of the pair is giving LHR the most trouble. The transmitter is basically just an LED and those things last forever. Just consider what is in most TV remotes. Those are mostly infrared.
At work we replace quite a few more receivers than transmitters. It's just the nature of the beast.