Flow sensor has two no flow states
Flow sensor has two no flow states
(OP)
I am inquiring about some ideas on how to handle a turbine pickup flow sensor, cheap model about $12. The sensor has three states: 1. NO FLOW - gnd, 2. NO FLOW - +V, 3. FLOW - variable frequency square wave. The signal is low pass filtered and drives the gate of an nmos fet indicating flow or not.
Problem: the flow state and the +V no flow state drive the gate of the nmos fet to on. Any ideas on filtering this signal short of an MCU?
Much appreciated
Cy Drollinger
Problem: the flow state and the +V no flow state drive the gate of the nmos fet to on. Any ideas on filtering this signal short of an MCU?
Much appreciated
Cy Drollinger





RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
It's been done with 555s, of course, but you may find that a small PIC is cheaper than the resistors you need for any analog solution.
Mike Halloran
Pembroke Pines, FL, USA
RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
http://www
RE: Flow sensor has two no flow states
Mike Halloran
Pembroke Pines, FL, USA
RE: Flow sensor has two no flow states
The peak detect at approximately 9V at the drain of FET_1 drives the gate of FET_2 (flow on signal)while the voltage divider at the gate of FET_1 is not enough to turn FET_1 on.
When the sensor stops at a 12V output also seen by the drain of FET_1 a the voltage divider Vgs large enough to turn FET_1 on dumping the current of 12V through a 100k resistor.
Cy Drollinger
RE: Flow sensor has two no flow states
Mike Halloran
Pembroke Pines, FL, USA
RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
RE: Flow sensor has two no flow states
Maybe it's just me but I cringe at the thought of using a 555.
RE: Flow sensor has two no flow states
Mike Halloran
Pembroke Pines, FL, USA
RE: Flow sensor has two no flow states
CY