Connect SEN0551 to DFR0918
Pedro.Sousa 2026-09-01 07:50:36 174 Views5 Replies I am having difficulty to get the signal on the software from the Gravity: Liquid Flow Sensor (SEN0551) to the Raspberry Pi GPIO Terminal Block HAT (DFR0918).
If i test it, I can listen the turbine rotating, I can see the Led from the GIO blinking but I cannot find any program that can red this pulse.
Do you have any template software that I can test it?
Thank you.
Thanks for the feedback.
The point here is also measuring during the raise up and down. I check it with the Multimeter and I detect that the voltage (when the turbine is rotating) never drops lower than 1.63Vdc… the maximum is ok, but the problem is never detect the rise down… therefore don't detect the pulse, even I see the GIO led blinking.
I try many configurations on the wiring, having some resistors in serie to pull down the pull-up, divide the Voltage throw Tension divider but never can go further down… when pulsing.
I believe the best case is to connect directly to the Arduino and then from Arduino to connect to the PI by USB… a bit frustrating but I think will be the solution here.
Appreciate your support. Thanks
Pedro.Sousa Two boards will also solve the problem. What project are you working on? I think your thinking is quite flexible.
In fact, many things that can be accomplished with one board can also be extended to two boards. When I was studying at school, I used the Raspberry Pi to do YOLO. Later, when I learned STM32 with the teacher, I expanded the project to use the Raspberry Pi as the upper computer and the STM32 as the lower computer for motor control. I think being able to solve problems is actually a good thing. Having two boards also means you have more interfaces, which can expand larger projects.
The SEN0551 wiki only has Arduino code. The sensor outputs 75 pulses per litre, so the logic is just counting rising edges.
On the Pi you can use RPi.GPIO with add_event_detect on the pin you wired the signal to. Same interrupt idea as the Arduino sketch.
Jason.Miao If possible, you could share your code, even the hardware connections. The clearer the problem description is, the easier it will be to solve.
