Post by thread:[PIC]: Tachometer RPM for car or metalworking mach

Hello all, I would like to make a tachometer all i can find on the web are examples of freq meters i would like to use: pic16F84 7x 7sement led's (20 000RPM) maybe an extra ic for each segment so that the multiplexing speed of leds is not important and a brighter less flikkering display is the result would like to measure the time_between_pulses and 60sec/time_between_pulses is RPM i would say update display and do it again is there maybe someone who has done this already or could point me to a project or maybe someone is willing to help with the code hope to hear from you luberth http://luberth.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> I would like to make a tachometer > all i can find on the web are examples of freq meters What's the difference!? A PIC CCP module used in capture mode is very useful for period measurement. You then do a divide to get the frequency. I've done a bunch of these all with slightly different wrinkles. One series of these used a 16C923 which has a CCP module and built in capbility to drive raw LCD digits. Once the input signal is converted to a digital pulse train, the rest is pretty much the PIC, a 4 or 5 digit LCD display, and wires. That's about as simple as it gets. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Luberth Dijkman wrote: > I would like to make a tachometer > all i can find on the web are examples of freq meters > > i would like to use: > pic16F84 > 7x 7sement led's (20 000RPM) > maybe an extra ic for each segment so that the multiplexing speed of leds is not > important and a brighter less flikkering display is the result > > would like to measure the time_between_pulses > and 60sec/time_between_pulses is RPM i would say > update display and do it again Hi Luberth! :o) Is this your first time on the Piclist? I have watched your plotter CNC page etc for a couple of years now, very nice pages. :o) The tachometer should be fairly easy with a PIC, but I suggest using the freq rather than period measuring as it has a lot of advantages. For a tacho you really don't want to display more than 2 times per second, or the display flickers and gets messy. So set the PIC to time for 0.5 second and just use an internal timer to count pulses. Then a simple multiply by 2 and display the data in RPS. The only use where it is better to measure period is when the revs are very low, like under 100rpm which is unlikely with an engine or a CNC spindle etc. :o) -Roman -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I've built an instrument that displays RPM/PERIOD/FREQUENCY on an LCD display, using an 'F84. You could modify the circuit & software to use LEDs if you so desire. It's overkill for your application, but you could study the code & modify it for your own needs. The program would be a lot smaller without the other two features (essentially,, the RPM section averages 10 cycles (pulses) to determine the RPM). Let me know if you want it. Dennis {Original Message removed}

Dennis, On Mon, 4 Nov 2002 09:52:10 -0500, Dennis J. Murray wrote: > I've built an instrument that displays RPM/PERIOD/FREQUENCY on an LCD > display, using an 'F84. You could modify the circuit & software to use LEDs > if you so desire. It's overkill for your application, but you could study > the code & modify it for your own needs. The program would be a lot smaller > without the other two features (essentially,, the RPM section averages 10 > cycles (pulses) to determine the RPM). > > Let me know if you want it. *I* wouldn't mind a copy of this program if you're offering! Cheers, Howard Winter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

May I have a copy please? Vyas PS. I am running a week behind in reading PICLIST. > I've built an instrument that displays RPM/PERIOD/FREQUENCY on an LCD > display, using an 'F84. You could modify the circuit & software to use LEDs > if you so desire. It's overkill for your application, but you could study > the code & modify it for your own needs. The program would be a lot smaller > without the other two features (essentially,, the RPM section averages 10 > cycles (pulses) to determine the RPM). > > Let me know if you want it. > > Dennis -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.