Artcile on IR distance measurement

[ardhuru]

The output isn't linear though if it matters to you.

http://www.acroname.com/robotics/par...P2Y0A02YK.html

Yes, that does look promising, though I wish the range was at least a foot or two more.

I could always use a lookup table. Or, I've noticed in a lot of exponential curves the reciprocal of a reading often fits on a straight line, ready to be used in an algorithm. (I'm no mathematician, so please forgive me if this sounds absurd). Will have to confirm it is so for this sensor in Excel.

Thanks,

Anand Dhuru

[Jerson]

The Sharp IR distance sensors IIRC are meant for small distances less than a couple of feet. I had tried to work with one of these sensors and found the range to be severely limited. I found success with the PING from parallax and subsequently rolled my own PINGer using some locally available Ultrasonic sensors http://robokits.co.in/shop/index.php...roducts_id=100 I didn't get too great a range, but, straight line performance was better than 5 feet.

Regarding the doubts about sensor reliability, you do get the sealed sensors that are meant for liquid measurement applications. The site which will give you a good handle is Maxbotix. This link shows a sensor meant for such http://www.maxbotix.com/MB7067__XL-MaxSonar-WRC1.html

[Ioannis]

Bruce asked if this is a commercial product.

If yes, do not try making your own sensor. In similar cases I used the MicroflexC US sensor. A great product with 4-20mA output. Powered from the 2 lines.

http://www.hycontrol.com/level_measu...onic_level.php

The other option ruce gave with the pot, wll not be very linear, though very cheap.

Ioannis

[mackrackit]

A pressure sensor at the bottom of the tank in an extra fitting. 0.43 psi/foot.

[Ioannis]

Unless the sensor is well isolated with a special cable too, this is also a good option (Classic 4-20mA too).

But in general is in my opinion, better not to immerse anything electronics in the water. Keep them out, in an controlled place.

Ioannis

[mackrackit]

Unless the sensor is well isolated with a special cable too, this is also a good option (Classic 4-20mA too).

But in general is in my opinion, better not to immerse anything electronics in the water. Keep them out, in an controlled place.

Ioannis

That is where snubbers come in handy to isolate the sensor. But a good stainless steel sensor should work with water just fine. I have used this type of thing with products ranging from a pH of 1 to 13.

Many options. What are the tank dimensions?

[El_AMPo]

Just to add a drop ,

I've built a proximity sensor from IR led + IR-VIs Phototransistor for the pic.

Really a low parts count solution and works like charm in the range of 2-30cm if you apply 2 or 3 layers of filtering.

Anyway, stay away from light reflection methods if you need an accurate linear response according to distance, or be prepared for resolution problems and lookup tables