Looking for a device that will be immersed in liquid, will emit light and measure how much of it passes through it.
Thinking about a glass pipe bent into a U-shape, with LED in one shoulder and light sensor in the other.
But when I think of making it myself, it seems that it will be fragile. Also ebay amazingly doesn't seem to have suitable long glass pipes.
Maybe there is a ready one available?
A simple drawing of what you are describing would really be helpful. If there is a LED on one end of the tube and a sensor on the other, how does that measure how much light goes through the liquid?
Paul
Paul_KD7HB:
A simple drawing of what you are describing would really be helpful. If there is a LED on one end of the tube and a sensor on the other, how does that measure how much light goes through the liquid?Paul
LED emits light, light leaves one shoulder of the U-shaped pipe into the liquid, enters another shoulder of the pipe and hits the light sensor.
yurivict:
LED emits light, light leaves one shoulder of the U-shaped pipe into the liquid, enters another shoulder of the pipe and hits the light sensor.
Explain how the liquid gets INTO the pipe! That is why the request for a drawing!
'
Paul
Paul_KD7HB:
Explain how the liquid gets INTO the pipe! That is why the request for a drawing!
'
Paul
The liquid doesn't get into the pipe. The pipe is dry inside. The light is emitted from one shoulder of the pipe by the dry LED, passes through the liquid, and is sensed by the sensor in another shoulder. It only needs to go through the liquid.
It might help to explain exactly what you are trying to accomplish. I understand what you propose, but aerated crystal clear water would read the same as mud water.
tinman13kup:
It might help to explain exactly what you are trying to accomplish. I understand what you propose, but aerated crystal clear water would read the same as mud water.
aerated crystal clear water would read the same as mud water
I am not sure why you think this is true. If detector has the right sensitivity range it should easily detect even small changes in liquid translucency.
Google "Arduino turbidity detector".
Leo..
yurivict:
aerated crystal clear water would read the same as mud water
I am not sure why you think this is true. If detector has the right sensitivity range it should easily detect even small changes in liquid translucency.
Because you will be seeing many thousand reflections, which are different from translucency.
Paul
Wawa:
Google "Arduino turbidity detector".
Leo..
Yes, thanks! I found this relevant thread: Turbidity sensor coding - Programming Questions - Arduino Forum
The only problem I have with it - it is made of plastic, therefore isn't suitable for food, and it is too small to be convenient.
yurivict:
Looking for a device that will be immersed in liquid, will emit light and measure how much of it passes through it.
Thinking about a glass pipe bent into a U-shape, with LED in one shoulder and light sensor in the other.
But when I think of making it myself, it seems that it will be fragile. Also ebay amazingly doesn't seem to have suitable long glass pipes.Maybe there is a ready one available?
I think the word you need is spectrophotometry. Actually that measures absorption across a spectrum of colours,
I guess you need a "light absorption meter", or a "liquid-cell photometer" or some such.
Why the U-bend? Surely that's going to lose light out the side? Or are you trying to measure back-scatter?
MarkT:
I think the word you need is spectrophotometry. Actually that measures absorption across a spectrum of colours,
I guess you need a "light absorption meter", or a "liquid-cell photometer" or some such.Why the U-bend? Surely that's going to lose light out the side? Or are you trying to measure back-scatter?
I meant to have a pipe U-shaped to that emitter (in one shoulder) can be closer to sensor (in another shoulder).
Why not just use 2 pipes?
A couple of test tubes would do.
Allan
If you make a drawing would be nice : ) sounds interesting idea
Another idea - use a single test tube with the emitter and detector mounted one above the other with a light barrier between them.
Then you could look for backscattered light.
If you modulated the transmitter at a particular frequency, then you could detect just that frequency and to a large extent exclude ambient light - like an IR remote. And a suitable optical filter on the detector would help too.
Since you have access to both the tx and rx, a synchronous detector would be very simple - measure the analog output of the detector both during and between tx pulses, and take the difference.
This applies whatever the geometry of the system.
Allan