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PICAXE Pinpointer

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  • #16
    My apologies for the tardy reply, the Picaxe code can't be exported to a regular PIC programmer due to the basic bootloader in the picaxe, sorry.
    As I suggested, the chips and in-circuit programming cable are extremely cheap (unlike a decent PIC programmer/development system) - just buy one :-)))

    Best regards

    Neil

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    • #17
      I should mention, if anyone really wants one, I can easily mail (worldwide) a pre-programmed Picaxe chip at enormous expense if that helps - just PM me (I'm joking about the expense, they're only about 2GBP +VAT :-) - about 3 USD + a dollar for my time )

      Cheers

      Neil

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      • #18
        hi igull

        i have interest in some programmed picaxe

        i will contact you next days i if have some time for etch pcb

        regards

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        • #19
          Hi Igull,

          Try this : http://www.sonsivri.to/forum/index.php?topic=43548.0

          Works for 16f88 & 12F683

          Regards,
          Hugo

          Comment


          • #20
            Hi Hugo

            No, hadn't seen this, interesting.

            I personally wouldn't do it as it's illegal.
            What they are doing is stealing from the good folks at picaxe. For the sake of a few (literally) measly pennies, they are taking the small profit they make on each chip (that's how they can run their business). Bear in mind that picaxe was designed as an educational tool too. Without the folks at picaxe, we wouldn't have such an outstanding and useful system. The stuff there is so incredibly cheap, I wonder why anyone would bother. No doubt they use the multi-platform FREE software to program with too!

            /stepsOffSoapbox :-)

            Cheers

            Neil

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            • #21
              @igull :
              I think there is a mistake in your schematic.
              One side of the coil is connected to the ground and the other side must be connected between C1 & C3.
              Am I wrong ?

              Another thing ; What is the inductance of the coil ? The diameter of the ferrite rod (7-8mm) ? What is the expected frequency at the input of the Picaxe ?

              Regards,
              Hugo
              Attached Files

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              • #22
                Originally posted by hugo View Post
                @igull :
                I think there is a mistake in your schematic.
                One side of the coil is connected to the ground and the other side must be connected between C1 & C3.
                Am I wrong ?
                Another thing ; What is the inductance of the coil ? The diameter of the ferrite rod (7-8mm) ? What is the expected frequency at the input of the Picaxe ?
                Hi Hugo
                You win the 1 euro prize - you are the only one that spotted my deliberate error
                Yes, of course you are correct, it's a colpitts oscillator - my schematic is wrong, sorry - I should just have scanned my notepad version rather than converting it to eagle. My veroboard layout is correctly wired however (I checked just in case!).
                I have no idea what the inductace of the coil is - there are probably online charts that can quickly give you an idea - it was a case of pulling turns until it was close to 40KHz which is the frequency - 25uS.
                Ferrite rod diameter is 9.525x70mm - actually an imperial measurement of 3/8" - from a 100 year old transistor radio
                I've attached an updated schematic.

                Cheers

                Neil
                Attached Files

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                • #23
                  @igull :
                  Only 1 Euro ! Too bad, I wish I had won more !
                  The oscillator frequency is enough for me.
                  I'll calculate the coil.
                  Thank you,
                  Hugo

                  Comment


                  • #24
                    Hi everybody,
                    I've made this pinpointer with success.
                    But my first tests were quite poor.
                    The detecting range was less than 1 cm for a 1 euro coin.
                    Several tests later, I can reach 2 cm !
                    My mods :
                    Same coil but C2 increased up to 570nF. This decreases the osc. frequency down to about 23Khz.
                    I re-wrote the basic code too :
                    ' PICAXE Auto Pinpointer
                    ' © Neil Gillies 2012-05-13 22:22
                    ' MOD Hugo 2012-06-20

                    ' Operation - TR1 is a standard colpitts oscillator approx 23KHz
                    ' At boot, PICAXE measures and stores the frequency count ('calibrate').
                    ' 'measure' loop tests the current frequency against calibrated - if > 'calibrated' + 'threshold', it beeps.
                    ' That's all it does :-)

                    #picaxe 08M

                    setfreq m4 '4MHz

                    symbol oscillator = 3 'leg 4 - nominal frequency 40KHz - 25uS
                    symbol beeper = 2 'leg 5

                    symbol calibrated = w0
                    symbol measured = w1
                    symbol tester = w2

                    symbol gate = b8
                    symbol threshold = b9
                    symbol x = b10
                    symbol difference = b11

                    let gate = 100 'mS
                    let threshold = 6 'offset counts from calibrated

                    calibrate: count oscillator, gate, calibrated
                    let tester =calibrated + threshold
                    gosub beepLo
                    pause 250
                    gosub beepLo

                    measure: do
                    count oscillator, gate, measured
                    if measured > tester then
                    gosub beep
                    endif
                    loop

                    beep: sound beeper,(120,5)
                    return


                    beepLo: sound beeper,(110,5)
                    return
                    Regards,
                    Hugo

                    Comment


                    • #25
                      Hi friends,

                      Did you try to use proximity sensor IC? Fo example TCA305, TCA505.

                      Regards.

                      Comment


                      • #26
                        some news on picaxe pinpointer?

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