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Forum Index : Microcontroller and PC projects : Webmite and Water Flow Sensor
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| Gerad Regular Member  Joined: 10/01/2024 Location: GermanyPosts: 42 |
Does anyone have experience with Webmite and Water Flow Sensor. I only find Python information. Who can help me ? |
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TassyJim Guru  Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
What type of water flow sensor? Most sensors use hall effect devices and send out pulses proportional to the flow rate. My sensors send approximately 300 - 400 pulses per litre so it is simply a matter of using the counting inputs and read the value every 30 seconds (or what ever time span suits your application). Jim VK7JH MMedit MMBasic Help |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
Hi Jim Thank you for your reply My test sensor is a Digiten FL-S401a Specs: 0,3-6l/min 3-24V F=98*Q(L/min) "F" probably means "frequency). But what does 98*Q(l/min) mean? Gerad |
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| Pluto Guru Joined: 09/06/2017 Location: FinlandPosts: 357 |
Q: waterflow expressed im liters per minute. example: 2 liter per minute would give a frequency of F=98*2=196Hz. Could also be F=196 pulses per minute. If you have the sensor, why not test and see? |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
Q = quantity. Frequency = 98 * Q Q = Frequency / 98 count the number of pulses in one minute and divide by 98 to give Litres per minute. Flows below 0.3 L/min will not be accurate. Flows above 6 L/min will not be accurate. My sensors are bigger at 50 L/minute but work the same and are 440 pulses per litre for one type and 330 for a different type. Jim Edit: Looking at some specs it might be pulses per second, not minute. A test will soon tell you which it is. Edited 2024-03-17 19:04 by TassyJim VK7JH MMedit MMBasic Help |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
It seems the FL-S401a sensor is the wrong one. The sensor should measure in the range 95ml to 570ml. I'll probably have to use an expensive laboratory sensor. Thanks Jim Thanks to everyone for your tips Regards Gerad |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Look on AliExpress: not too expensive for low flow rate versions Example Another Mike Edited 2024-03-17 19:41 by Solar Mike |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
If the FL-S401a sensor is 98 pulses per second for 1 litre/min that gives you 98*60 or 5880 pulses per litre. Measuring 95ml should be easy. Jim VK7JH MMedit MMBasic Help |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
The sensor delivers an impulse. Faster or slower depending on the flow. > SETPIN GP7, FIN > PRINT PIN(GP7) The result is 0 What am I doing wrong ? Gerad |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
Hello Mike Thank you for your AliExpress note. Was very helpful. Have a nice Day Gerad |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9114 |
Is the output of the flow sensor open collector? If it is you will need a pullup resistor |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
hi matherp These are the sensor specifications Frequency: F=98 * Q (L / Min), error: ± 2% Flow range:0.3-6L/min Maximum Consumption current:10 mA(DC 5V) Working voltage range:DC 3-24 V Pressure range: 0-0.8MPa Storage Temperature:-25-80℃ Output Waveform:Square Wave,output pulse singal. That's all I know Gerad |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
Assuming you are running the sensor on 3.3V to match the picomite, try a 1k resistor from 3.3V to the output (yellow) lead. If you use COUNT instead of FREQUENCY, you can specify an internal pull-up instead of the external one. Jim VK7JH MMedit MMBasic Help |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
I have been using similar sensors recently measuring water flow from a distant pump into a header tank; running off 5v used a 10K resistor from output (yellow) to 5v, the sensor output can start from a logic low or high depending on where its impellor rests at initial start up. In your code look for a transition edge and count the pulses over a set time. You can test it on the bench by gently blowing through the input tube. Note they have a directional arrow for water flow. Cheers Mike |
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| Gerad Regular Member Joined: 10/01/2024 Location: GermanyPosts: 42 |
it's a mystery to me I use a new Raspi Zero W with a Freenove breakboard. All pins are equipped with LEDs. The LED of GP7 reacts to the sensor pulses but the input does not count. GP7 has a 1K pullup resistor. The sensor is connected to 3.3V. What's going wrong? Maybe the sensor doesn't work correctly with 3.3V Gerad Edited 2024-03-18 20:28 by Gerad |
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