Hey guys,
I’m planning on using two Seeed Studio water flow sensors for a project and have a few questions about the output signal on the sensor.
The data sheet states that the output signal voltage will be 4.5v at an input voltage of 5v. Is it safe to assume that the output voltage will be proportionately higher at 9v input voltage?
Also, what is the highest voltage that can safely be placed on a digital input pin (without blowing up my board!!! lol)
I have multiple sensors (flow and pressure) and did not want to draw to much current through the Uno, so on my power supply I have 9 volts feeding the Arduino and wanted to pull the power directly from the supply. I can simply add a 5v power reg and be done with it but wanted to make sure that I could not use 9v before doing extra work.
RobDrizzle:
I have multiple sensors (flow and pressure) and did not want to draw to much current through the Uno, so on my power supply I have 9 volts feeding the Arduino and wanted to pull the power directly from the supply. I can simply add a 5v power reg and be done with it but wanted to make sure that I could not use 9v before doing extra work.
Thank you.
Hall effect sensors draw very little current, I don't see why you can't power them from your Arduino's +5vdc pin. However using an external +5vdc regulator would work fine as well.
I have the data sheet in front of me, it states 15mA @5V.
I have made a few tests for my "Barnduino", just powering the sensor from my Duemilanove, it was fine, even when powered from my eee's USB port.
As an aside...
When I did my tests it was a fairly warmish day, around 28C, I had the sensor on the main water supply to the barn.
After the 25mm line goes into the barn it goes into a 50mm pipe which feeds 4 25mm hoses that feed 4 water lines on the southern half of the barn.
The northern half of the barn has the same setup.
With 5000 odd birds drinking, you should have heard the whine coming from the sensor as the little turbine span around!
It was reporting between 180 and 380 litres/hour!
I thought that was a "tad" high, so I turned of all 4 drinker lines and tested them 1 at a time.
The sensor then reported 45 to 90 litres/hour, after sunset when all the birds were asleep the sensor reported no flow.
I then snuck in and tried operating a single drinker cup and the sensor registered about 2 litres/hour.
As a simple test it worked well, but the final implementation will use a sensor on each drinker line.
The aim here is not to measure total flow but alert me when something has gone wrong, like when the little darlings break a drinker cup off the line or open the taps on the other end.
With a sensor on each line I'll know which one to turn off in a panick!
Depending on how things go I may add a solenoid valve to cut the water supply in the event of "abnormal" flow rate.
Developing this is WAY more fun than mopping up 2000 litres of water and the mess that goes with it!