Liquid Flow meter using infrared sensors

Discussion in 'Homework Help' started by luciansm, May 19, 2014.

1. luciansm Thread Starter New Member

May 19, 2014
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0
Hi, in my final graduate project i'm thinking to project a liquid flow meter using infrared sensor (phototransistor) and a microcontroller.

The main idea its to do 2 horizontal lines of tranceivers and receivers with a know vertical distance between then.

The infrared receiver it will generate a Vout that depends of the opacity of the liquid.

My idea is to measure in the first line, the Vout voltage with the A/D converter of the microcontroller and the time that the voltage was measured.
The second line of the receivers it will do the same measures (Vout and the time).
With the measures done, the time of the SAME Vout measures it will be compared, and with this data i can measure the speed of the liquid.

An example:

The firts line receivers generate 3.2V at Vout that was readed at A/D converter at the time 300ms.

The diference between the time of the measures is:
320 - 300 = 20ms.

If the distante between the line of the receivers is 3cm, i can measure the speed:
speed = 3cm/20ms

The question is: It's possible to do this or the complexity it will be huge?

Any ideas how to start?

Thanks.

2. shteii01 AAC Fanatic!

Feb 19, 2010
3,500
511
The only way I see this working is to use some coloring agent when you need the speed measurement. Meaning, the fluid normally has opacity X, when you want to measure fluid velocity you introduce a coloring agent, the fluid opacity changes Y, the coloring agent passes through first sensor and time is recorded, the coloring agent passes through the second sensor and time is recorded, the fluid returns to its original opacity X, your uC does the math and displays the result.

The change in opacity is the key to taking measurement.

I think food coloring should be safe for most nonindustrial applications.

luciansm likes this.
3. luciansm Thread Starter New Member

May 19, 2014
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0

yes, the change of the opacity of the liquid it will be very important.

I was thinking to test it with process that the opacity of the liquid changes during the time.
I think there is a lot of industrial applications that the liquid changes during the process.
Like cow milking, coffee machine and others.

4. THE_RB AAC Fanatic!

Feb 11, 2008
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1,305
Or you could google for "electronic liquid flow rate sensor" and find hundreds of ready made flow rate sensors that are reliable AND already calibrated.

5. luciansm Thread Starter New Member

May 19, 2014
3
0
Hi THE_RB , thanks for the reply.

Yes it has manny devices ready made, but the objective is to build one for my final graduate project in Computer Engineer.
I'm looking for suggestions and hints to where start.