Questions about the:
PICList Project The Weeder Frequency Counter PIC 16F84 port by Peter Cousens

Questions:

• esteban.adra at spamgmail.com asks:

  Im going to build this circuit but simulating on proteus i get "Overflow" from the lcd, no matter how i change the freq. Do you know if its a proteus problem ? I need the circuit to really work, it's for a schoool project. Thanks !
  

  +
• Giulio Coslovich asks:

  Hello
  I have built this circuit:
  http://maxhobby.altervista.org/frequenzimetro16f84/pfc50shc.gif
  and when I use the hex file of this site the 16x1 display shows only 8 black squares.
  But connecting a 16x2 display with the pin order like on this site makes it works perfectly.
  How can I make it work with a 16x1 display and with the pin order of the picture?

  +
• microtek at spamcenturylink.net asks: " Is there any chance that a PC board is still available for this project?" James Newton of MassMind replies: I don't believe it is. If you decide to have some made, I'd be willing to go in with you on a batch purchase.+

  +

• soti_159 at spamhotmail.com asks: " This frecuency meter wokrs fine or what...??? i read that it has error: wen the frecuency is 511 KHz it shows 255 KHz? It's true that afirmation??" James Newton replies: It seems unlikely to me, given how long this project has been around and how many people have played about with it. But anything is possible. That is the nature of open source systems. Try it and if you find the problem, please post a solution.+

  +

• contact2snehal at spamrediffmail.com asks: " real time application of 50MHz frequency counter
  " James Newton replies: Counting frequency of electrical pulses up to 50Mhz.+

  +

• aiza_ice9 at spamyahoo.com asks: " if I want to use LCD instead of 7-segment ,what change I do in hardware for PIC16F84A?""
• josephjeevan at spamrediffmail.com asks: " can anyone explain the working of this circuit???
  mean, block-block??
  " +
• Ooi Joe Earn asks:

  I faced the problem that mentioned above that the MPLAB ICE v7.40 software showed a warning message when builded the source code.How to update the software so that i can build it?

• barryhyland at spamiol.ie asks: " Is it possible to buy already assembled, a cheap frequency counter with LCD display and battery suitable for use with an Icom-R5 scanner?" +
• msn_etemad at spamyahoo.com asks: "
  if I want to use four 7-segment instead of LCD,what change I do in hardware?" +
• lu2dlt at spamfullzero.com.ar asks: " Thanks James, solve with the code 8x2 Thank you very much to it. Luís Alberto Argentina. " +
• lu2dlt at spamfullzero.com.ar asks:

  installed Weeder frequency counter with PIC16F84a and
  Fordata 16x1 LCD display unfortunatelly
  dosen't work, but everything seems to be good.
  The lcd shows black square on first eight character,
  and nothing all.Have You any idea what is the problem
  with this circuit? Best regard, please help me..
  My email lu2dlt@fullzero.com.ar

  goran roglic of goran replies: Hello ! I have a same problem with my PIC 16F84A, only 8 black characters. Did You solve a problem? Please if, can You help me about that? Thanks Goran+

  +

• srini vasan of ms electronics asks:

  installed Weeder frequency counter with PIC16F84a and
  CRYSTALONICS CDM16116 LCD display unfortunatelly
  dosen't work, but everything seems to be good.
  The lcd shows black square on first eight character,
  and nothing all.Have You any idea what is the problem
  with this circuit? Best regard, please help me..
  my email id: elektronik_ms@yahoo.com
   

• hichkok at spamhotmail.com asks: " do u have a flow chart for this project " James Newton replies: No. If you develop one, please consider sharing.+

  Y.C. Tseng replies: I'd build this Frequency counter and use wct5 / wct6 code in 16F84A. The codes work very well for me. Just remind that make sure set everything off and clock in HS mode.+

  + derkjan75 at spamhotmail.com asks: " Can somebody change the code for the PIC16F84A and mail it to me? thanks" +
   

• john.paterson at spambbc.co.uk asks: " shouldn't RB0 from the pic goto DB0 on the LCD display, with RB1 going to DB1 and so on?" +
   
• oswa_mene at spamyahoo.com.mx asks:

  I installed frequency counter with PIC16F84A and a 16x1 LCD
  but the LCD shows only the 8 left characters with the WCT5.asm above. ¿can anybody send me please the right code? I can give you an alternative imput circuit for this counter.
   

  
   
• Where can I find the modified source code for the PIC 16F84A
  +
• edel at spamgr8.co.za asks: " I will create a seven segment diode disply addon schematic if someone will do the software.
  thanx ed " Y.C. Tseng replies: Maybe this webside you can take a look...+

  Y.C. Tseng replies: Maybe this webside you can take a look... http://www.saturn.dti.ne.jp/~khr3887/fcp.html

  +
   

• researcher at spamfreemail.it asks:

  I would like to use this frequency counter in an ancient radio receiver so does anybody know how I can subtract a constant value? ex: it should be interesting subtract 10.7MHz or 455KHz from the red value.
   

• criradu at spamyahoo.com asks:

  I wander there is any way to establish a 4 bits paralel interface between pic and LCD. I want to put a 64 frequency devider to increase the masured frequency. I need a pine from the pic to set it high if the frequency devider is in use, and low if is not. Any idea...?
  Thenks for your atention! Radu
   

• Ian asks:

  Can anyone modify this code so it will multiply the frequency by 64? and display upto 1300 Mhz (or even 3000 Mhz) on the display.
  
  I have found that the circuit can be easily modified to easily read these frequencys. I accept that it might not work so well at the lower end.
  
  Its quite simply using a /64 IC. If anyone can write this code, it would be a great asset, and I will put a link to the modified circuit.
  I have looked at the program, but my software simulator (labcenter Isis) cant handle all of this code (and yes, im lazy :-)
   

• dudasz at spammatav.pecs.hu asks:

  I installed this counter with wm-c1601m-1tnnc LCD.
  The LCD shows some black square, and nothing all.
  Have You any idea what is the problem with this circuit?
  
  http://www.wintek.com.tw/ModuleList.asp?LcmType=&DispType=CHARACTER&ModuleNo=WM-C1601M-1TNNc
   

• hi, anyone can modify this to use single +5v power supply? +
   
• srousseau at spamcomlab.com asks: " Wich type of LCD may I use? S6A0069, HD44780 or other?" +
   
• Is there a PC Board layout for the Weeder Frequency counter?+
   
• tzhang asks: " hi, it is difficult to buy MPF102 and 2N4403, may i replace them
  use 2sk83 and 9015 (or 2n3906)?
  thanks!" +
   
• tzhang Says: " i got the answer. the secret is 74hc132 and fr10 .
  the author is very clever! " +
   
• tzhang at spamwtusm.edu.cn asks:

  hi,
  i am confused with this:
  This counter use /256 prescaler, so i think it can't measure the
  freq below 256 Hz, but it CAN measure the freq below 256 Hz very well, would you like to give me the answer? thank you veru much!
   

• scs_r at spamindiatimes.com asks: " How Can I use 7 segment LED instead of LCD in 50 MHz Frequency counter kit. I am novice to PIC16F84.
  Thanks in advance."
  James Newton replies: You would have to A) redesign the display drive circuit and B) re-write the code that does the display. This would not be an easy task.+

  +

• dudasz at spammatav.pecs.hu asks:

  I installed frequency counter with PIC16F84 unfortunatelly dosen't work, but everything seems to be good. The LCD shows some black square, and nothing all.
  Have You any idea what is the problem with this circuit? Best regard, Zoltán Dudás
   

• r_manione at spamyahoo.com asks: " Hello: I would like to know whether a PCB design is available for such an interesting project.
  thanks in advance. Roberto"

  Try http://www.weedtech.com + + or see above
   

• What kind of 1x16 display I should use? Are they all same standard type? ...so that pinouts and inits are the same?
   
  James Newton replies: Any 1x16 with an 8 bit parallel interface should would, but the pinouts are NOT standard and so you will need to make sure the correct signals are connected to the correct pins on the PIC. The signal names (e.g. D0, RE, etc...) are standard.+
   
• cklymko at spamhotmail.com asks:

  I'm stuck with a display that only shows the first 8 characters. It seems that anything after that needs to be addresses as if it were on line 2 of the LCD. Anyone know how to make this work short of replacing the LCD?

  See the 8x2 LCD code +
   

• nojunkmails123 at spamyahoo.com asks: " I don't know why mine cannot measure above 39.XXX MHz, above that, the LCD just doesn't display anything. Can you help me figure it out? Thanks." +
   
• tkoch at spamrogers.com asks: " Why do you use the 74HC132 in your circuit? And can I use a LCD with a back light and a 7805 with a 13V DC 1 A power supply?" +
   
• padlam at spamtcp.co.uk asks:

  Can anyone explain what the 74hc132 does? My freq meter works if I pump an oscillator into the RTCC pin of the pic, but doesn't if I come in to the 74hc132.
   

  je at spamnanosoft.hypermart.net Answers:

  The 74HC132 is actually set up as a multiplexer, so it can read either new count data or the output pulses from RA2. To understand why this is done, one must remember that the prescaler of the TMR0 in the PIC is not readable. Now, being able to feed it pulsles means that you can just keep ticking it over until it gives, allowing you to get an extra 8 bits of accuracy.
   

• Aussieglider at spambigpond.com asks: " Can this be modified for better resolution (0.001hz). I only need maximum frequency of 1kHz, but need to measure mostly from 0-10 hz"
   
• callsaver at spamiolinc.net asks: " does the pic16f84 convert with your upgrade program without any changes to the weeder board? Thanks, Ken.."
   
• macavei_andrei at spamyahoo.com asks: " www.andreimacavei.go.ro where can i find schematic of this frequency counter?"

  Answer: From the link to the circuit, above.
   

• callsaver at spamiolinc.net asks: " I need a frequency counter like the one shown, will it count on a square wave and how much does the kit cost and the assembled version? Thanks, Ken."

  As the web page says, these questions should be directed to Weeder Technologies.

Comments:

• Most likely, the doubled result in the frequency measurement is due to the poor quality of the generator, which gives uneven and distorted signals.+
• It just shows a blinking black square, nothing else.+
• milroc at spamfullzero.com.ar " Hello there was any possibility of using a pic 16F628
  From Thanks" +

See also:

• skylimit000 at spamgmail.com refers to

  http://www.microwave.gr I constructed the counter. Only the 8 of the 16 digits light up showing black rectangles only. The counter does not do anything. What could be the fault?

  James Newton of James Newton's Massmind replies: Almost anything. Find a middle point in the circuit, figure out what you should be seeing at that point, and test it with a meter or 'scope. If it's good, look towards the output, if it's not, look towards the input. Keep dividing it in half till you find the first problem.+

  +

  .