LCD Frequency Meter

Hi everyone!

I have a project that i need help on starting.

I have a flow transducer that outputs a frequency range which changes at different water flow rates.

I would like to convert this frequency output into a litre/minute calculation on a LCD display.

I am a novice, any tips or directions? Any help is welcome!

Use a microcontroller.

Yes I have looked into this but unaware of which microcontroller to use. I have a MPLAB In-Circuit Programmer.

InfernoJaffa said:

Yes I have looked into this but unaware of which microcontroller to use. I have a MPLAB In-Circuit Programmer.

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The use a PIC, what is the frequency range of the transducer?.

Nigel Goodwin said:

The use a PIC, what is the frequency range of the transducer?.

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The datasheet for the flow sensor can be found here; **broken link removed** .

Is this a hobby or a "work" project?

ronsimpson said:

Is this a hobby or a "work" project?

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This is a hobby with resources from work.

InfernoJaffa said:

The datasheet for the flow sensor can be found here; **broken link removed** .

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Nice and slow then, so should be an easy enough job to do.

Nigel Goodwin said:

Nice and slow then, so should be an easy enough job to do.

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Thanks! Any starter hints/tips?

If you check the EPE website, they have published a number of counter projects, or MicroChip have an appnote for a frequency counter.

Nigel Goodwin said:

If you check the EPE website, they have published a number of counter projects, or MicroChip have an appnote for a frequency counter.

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Hi Nigel,
Thanks for your reply, I have looked at the microchip appnote using a PIC16C54 and found that the source code snippet is written in assembly language. I have done little assembly at college but feel that the C language would be a wiser choice for me. I also tried searching for the EPE website you had mentioned and found a site called EPEMag, was this the one you meant? I couldn't find much on that website.

I have found other projects using an Atmel chip with easy to understand source codes although programming the chip will not be easy. I would like to design the PCB board to include on-board programming as this will be easier to reprogram in the future (this should be a simple addition at the end).

The PIC chips I used at college were PIC16F84A and were programmed in assembly language.

Edit: I have learnt that I can connect the frequency directly to timer1 and measure the counts over a 1 second period. I can then take the value from timer 1 and calculate and display the flow rate.

I have attached a flow chart of what I would like the PIC to do.View attachment 61806



Can anyone suggest a good PIC to use, I have found the PIC 16F874 with Timer1 function although it seems to have more features then I need (40Pins).

I have found another PIC chip called PIC12F683. Simple 8 pin chip with Timer1.

A simular project I have found when using this chip is https://picboard.blogspot.com/2010/09/experiment-no-6-pic12f683-timer1-used.html . Althought this is not connected to a LCD display (does this chip support this?).

InfernoJaffa said:

I have found another PIC chip called PIC12F683. Simple 8 pin chip with Timer1.

A simular project I have found when using this chip is https://picboard.blogspot.com/2010/09/experiment-no-6-pic12f683-timer1-used.html . Althought this is not connected to a LCD display (does this chip support this?).

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It's only an 8 pin chip, so it doesn't really have enough pins to connect an LCD - but an 18 pin one does.

Thanks for verifying this Nigel.

I have found this https://www.best-microcontroller-projects.com/pic-frequency-counter.html online and plan to follow it, I will then edit the output to calculate flowrate instead of frequency. Hopefully it's as easy as that .
Just have to source the components.

I will let you know how I get on and if anything unexpected jumps out at me.

Can anyone tell me the difference between these two PICs:
PIC16F887-I/P 20MHz - £1.89
PIC16F877A-I/P 20MHz - £4.09

I have chosen the PIC16F877A but in terms of cost the difference is 'noticeable'.

please see the ratees here
that much difference is not found.
https://uk.rs-online.com/web/c/?sra=oss&searchTerm=pic16F877&x=0&y=0
neither here there is such vast difference.
https://uk.farnell.com/jsp/search/b...search&Ntt=pic16f877&Ntx=mode+matchallpartial

mvs sarma said:

please see the ratees here
that much difference is not found.
https://uk.rs-online.com/web/c/?sra=oss&searchTerm=pic16F877&x=0&y=0
neither here there is such vast difference.
https://uk.farnell.com/jsp/search/b...search&Ntt=pic16f877&Ntx=mode+matchallpartial

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Thank you!

InfernoJaffa said:

Can anyone tell me the difference between these two PICs:
PIC16F887-I/P 20MHz - £1.89
PIC16F877A-I/P 20MHz - £4.09

I have chosen the PIC16F877A but in terms of cost the difference is 'noticeable'.

Click to expand...

The 877A is a very old device, similar to the 16F84A - modern devices are MUCH cheaper, presumably to encourage people to stop using the antique ones

Presumably the 887 is the modern replacement for the 877?.

Sorry , perhaps i mistook both for 877

Nigel Goodwin said:

The 877A is a very old device, similar to the 16F84A - modern devices are MUCH cheaper, presumably to encourage people to stop using the antique ones

Presumably the 887 is the modern replacement for the 877?.

Click to expand...

Thanks for confirming this, so I should be fine in using the newer chip as a replacement without any issues?