counting water drops dripping from IV bottle

greeting everyone,

I am doing a school project. I want to count the number of drops dripping from the intravenous bottle which are used in hospitals. I have tried using laser emit and LDR sensor. I have tried passing the drops between the laser emit and LDR sensor placed in line. But I drops were not detected. Can anyone give me another alternative for my project.

Thankyou in advance

LDRs are very slow to respond to changes so that may be why it did not work. An IR photo-transistor is many times faster than an LDR and may detect the drops.

thankyou so much

which one should i use as the light source on the IR photo-transistor??? a laser or a IR light source?

I would think that a nice bright IR LED would work, but I don't know your setup so no guarantees. I would be very wary of using an IR laser except where it can be totally enclosed so that there is no danger to anyone.

You will need to test the IV tubes to see if they will pass IR light. Remember the light will have to pass through two thicknesses of plastic as well as being diffused by the liquid.

Paul

The reference in reply#1 shows transmitted and reflective modes of operation. You may want to experiment to see which gives the best response to the drop.

Unless you enclose the drip chamber in a lightproof box, which is not really appropriate as the drips must be visible to others, you need to use modulated light - whether it is visible or infra-red - so that the sensor does not respond to illumination by ambient light.

The second problem is alignment. You may need to allow for the drip chamber not to be precisely vertical so the drops do not fall down the centre. Also, a drop is of course, transparent, and as it obstructs the light beam, it does not do so completely, so you are looking for a decrease in the light but not complete blocking. An interesting alternative is to detect scatter instead - have a black pad opposite the light source whether laser or not, and sense perpendicularly to the beam. Again, modulated.

You may not realise this, but while optical drip sensors were used at one time for this purpose, they proved to be quite unreliable and have therefor been completely replaced by peristaltic pumps.

Paul__B: Also, a drop is of course, transparent

Not with a banana bag, so:

Paul__B: Also, a drop is of course, often transparent

;)

Maybe you could try something like this? https://www.ebay.com/itm/254175261156

Here are some more links on how to proceed with this

https://infusionnurse.org/2011/03/25/calculating-and-counting-drops/

https://www.ee.iitb.ac.in/~spilab/Publicatios/bio_vision01_kamble_drip_rate.pdf

neiklot: Not with a banana bag, so:

What, praytell, is a "banana bag"?

Banana bag, bright yellow and full of all manner of goodness. My son has had near-miraculous recoveries with call outs to collapsed patients who looked at death's door and then walked off like Lazarus after a bag full.

Back in August 94 I published a circuit to count and time drips in order to show the emergence of chaotic behavior as the drip rate increased. I made this circuit.
BBC132D.jpg

The diagram also showed why you got a double pulse from transparent drops.
You don’t need the 74LS74 when using an Arduino.

groundFungus: I would think that a nice bright IR LED would work, but I don't know your setup so no guarantees. I would be very wary of using an IR laser except where it can be totally enclosed so that there is no danger to anyone.

thankyou so much for your suggestion

Grumpy_Mike:
Back in August 94 I published a circuit to count and time drips in order to show the emergence of chaotic behavior as the drip rate increased. I made this circuit.
BBC132D.jpg

The diagram also showed why you got a double pulse from transparent drops.
You don’t need the 74LS74 when using an Arduino.

thankyou so much for your help sir. btw can I know the code how to interface IR source and IR receive to count the number of drops

Paul_KD7HB: You will need to test the IV tubes to see if they will pass IR light. Remember the light will have to pass through two thicknesses of plastic as well as being diffused by the liquid.

Paul

that is a really good point, I will look into it

hemanth09_: btw can I know the code how to interface IR source and IR receive to count the number of drops

You just wait for the pin to go high, then wait for it to go low, then increment your count.

Another way to count drops may be a piezo (aka knock sensor). It'll produce a signal when a drop hits it.