Flow Sensors revistied
in [Design]
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From: JosephKK on 11 May 2010 05:16 On Sun, 09 May 2010 15:27:15 -0600, hamilton <hamilton(a)nothere.com> wrote: >On 5/9/2010 1:37 PM, John Larkin wrote: >> On Sun, 09 May 2010 13:28:51 -0600, hamilton<hamilton(a)nothere.com> >> wrote: >> >>> >>> I have been asked to build a digital to analog circuit. >>> >>> The flow sensor: >>> http://www.gemssensors.com/uploadedFiles/Literature/Spec_Sheets/FT210_1124.pdf >>> >>> has a digital pulse output proportional to the flow. >>> >>> I would like to create an analog detector, so when it has reached a >>> minimum flow rate, a logic level is triggered. >>> >>> I am a firmware guy and know how to do this with a PYFMC[1]. >>> >>> I would like to get some suggestions on how to do this in analog. >>> >>> >>> thanks >>> >>> hamilton >>> >>> [1] Pick Your Favorite Micro Controller >> >> >> You could use my Double-Tach circuit followed by an analog comparator. >> >> ftp://jjlarkin.lmi.net/DoubleTach.jpg >> >> >> Or maybe just a couple of cascaded retriggerable one-shots, if all you >> need is the single underspeed indication. That's simple. > >Thanks, > >Yes, underspeed is the goal. > >Just an output logic level going to another micro that controls the rest >of the system. > >> >> >> Nice looking sensor. What does it cost? > >AAck $100 each !!! > > >The boss thinks he need the accuracy. > >With the other comments, I will use a PYFMC [2] and just count pulses. > >The data sheet states the range is 37 to 917 Hz. (.1 to 2.5 LPM). > >hamilton > >[2] This time I'll use an AVR. Next question. How fast does it have to respond? Third question. How touchy is the system at detection threshold? |