Hi Rob, I usually always use the classic Serial method so I think two tones are needed. The time between the commands is not short because they are handcrafted.
Op vrijdag 25 februari 2022 om 09:16:48 UTC+1 schreef hans: > Hi Vasiele and others. > I was born before the last world war and I suspect most of you after it. > I hope it stays that way!! > Great, I can study today again. Thank you. > > Op vrijdag 25 februari 2022 om 06:58:52 UTC+1 schreef vasile: > >> Kiste, not only the ZX81 but Sinclair Spectrum and most of it's clones >> did the same. >> The biggest problem was the tape speed variation (among the volume >> variation which was corrected in romanian clones -and we had more than any, >> I recall 5 different types). >> >> Hans, on the actual PIC18 series on which JAL works ( presuming you will >> do with JAL) you might have some sampling speed issues. You need at least >> 7.5us for an ADC sample and according to Nyquist theorem you need not 2x ( >> which is pure theoretical) but at least 4x faster sampling than maximum >> frequency you are recording. >> After your AD is sampled, the PWM is not an issue, but you might >> experience a small delay between real recorded speech and the PWM filtered >> one. >> If you plan to add voice for your puppet, then limiting to 4KHz may be a >> good choice. >> >> best wishes, >> hopefully not WW III, but in pace for playing nice... >> >> On Thu, Feb 24, 2022 at 10:38 PM 'Oliver Seitz' via jallib < >> jal...@googlegroups.com> wrote: >> >>> Hi Rob, >>> >>> connecting two PICs is not like an audio recording. Better connect the >>> pic to your soundcard to record and then playback, that way you'll get >>> something similar to a tape recorder. >>> >>> The difficulties when using audio equipment are (at least): >>> >>> - only alternating current is transmitted >>> - the volume is never exactly the same >>> - the frequency range is limited to like 100Hz-10kHz >>> - the line level voltage is less than 1V >>> >>> Reading should be possible by most PICs which have comparators. Only a >>> resistor is needed, then you can detect zero crossings. >>> >>> The Sinclair ZX81 used audio equipment as storage. A burst of three >>> oscillations coded a zero, five coded a one. The output was low-pass >>> filtered. You usually had to try loading a program several times, slightly >>> adjusting the volume, until you got lucky. >>> >>> Greets, >>> Kiste >>> >>> Am Donnerstag, 24. Februar 2022, 19:56:01 MEZ hat Rob CJ < >>> rob...@hotmail.com> Folgendes geschrieben: >>> >>> >>> Hi Hans, >>> >>> If I understand you right the only thing you want to do is to record a >>> signal or a sequence of signals on a casette player that can be used to >>> trigger something when the recording is played back right? >>> >>> If my initial suggestion would work - which may work since I have the >>> idea that my Apple II did more ore less the same thing - I could give it a >>> try to do a proof of concept. >>> >>> I may have a the problem that I do not have a casette recorder but I >>> could fake it by just connecting two PICs to see if that works. The final >>> test could then be done by you. >>> >>> Which PIC type are you using? >>> >>> Kind regards, >>> >>> Rob >>> >>> >>> >>> ------------------------------ >>> *Van:* jal...@googlegroups.com <jal...@googlegroups.com> namens hans < >>> hansvanve...@gmail.com> >>> *Verzonden:* donderdag 24 februari 2022 17:07 >>> *Aan:* jallib <jal...@googlegroups.com> >>> *Onderwerp:* Re: [jallib] PWM serial audio transmission >>> >>> Another piece of text: >>> So far I've done everything with MIDI. I used one midi channel for the >>> actions with a general command type. Then 2 data, one for the device nr >>> (16) and one for the command. (0-128) >>> This has worked well for years, but it does require a complete MIDI >>> sound package. >>> >>> Op donderdag 24 februari 2022 om 16:55:46 UTC+1 schreef hans: >>> >>> Hey , >>> I have tried a circuit with an MT8880 but the ICI has failed. I did hear >>> the 16 tones, but when I wanted to receive them, the chip gave up the ghost. >>> In theory I understand your suggestions well, but developing something >>> like this is not easy for me. I'm just a LEGO builder. >>> regards >>> Hans >>> >>> Op woensdag 23 februari 2022 om 19:30:37 UTC+1 schreef >>> rob...@hotmail.com: >>> >>> Hi Hans, Kiste, >>> >>> You can still by DTMF decoders and I assume also DTMF encoders. Just >>> look at for example Aliexpress and type DTMF. >>> >>> But another suggestion. Many, many years ago I had built an Apple II >>> and I used cassette tapes to store and load games which was using tones >>> generated by the Apple II itself using two tones, one for high, one for low >>> and one as a lead-in tone (not sure in the lead-in tone was another tone) >>> to synchronze the start of the recorded program. You would not need this >>> lead-in tone in your case >>> >>> So I think it may not be that complex: >>> -) For recording on casette, generate this dual tone by the PIC via PWM >>> or maybe it is also sufficient to generate one tone in case of a 1 and no >>> tone in case of a 0 but I think this will be less reliable. >>> -) For playback, measure the length of the recorded PWM tone. If is is >>> within a certain range you accept it as a one and in case of two tones the >>> lower tone could be zero and the higher tone is one. >>> >>> As long as the tone frequency is not too high, I think this could work. >>> >>> A more advanced solution would be to use a phase locked loop (PLL) but I >>> am not sure if it will work. The PLL locks to the input signal so the >>> voltage that controls the oscillator goes up and down to follow (lock on >>> to) the input signal and this oscillator voltage signal could then be used >>> by a comparator of the PIC to detect a high or low tone. You can also use >>> the oscillator of the IC to generate the two tones by controlling the >>> oscillator voltage by the PIC. A typical IC for that is the HEF4046. I have >>> used this IC many many years ago too. This solution may be bit over the top >>> since you only want a kind of trigger signal >>> >>> But maybe the first solution is more doable. Just give it a try. >>> >>> Kind regards, >>> >>> Rob >>> >>> ------------------------------ >>> *Van:* 'Oliver Seitz' via jallib <jal...@googlegroups.com> >>> *Verzonden:* woensdag 23 februari 2022 09:58 >>> *Aan:* jal...@googlegroups.com <jal...@googlegroups.com> >>> *Onderwerp:* Re: [jallib] PWM serial audio transmission >>> >>> Hi Hans, >>> >>> 20 years ago I would have suggested using DTMF, but the decoder chips >>> are rare these days... >>> >>> PIC controllers include various peripherals which can be used to encode >>> and decode DC-free signals (which, apart from the frequency below, say, >>> 10kHz, is the requirement to be recorded as audio). On/off keying or >>> frequency shift keying are the easiest, I think. Which chips are you going >>> to use? >>> >>> Greets, >>> Kiste >>> >>> Am Mittwoch, 23. Februar 2022, 09:15:43 MEZ hat hans < >>> hansvanve...@gmail.com> Folgendes geschrieben: >>> >>> >>> Hello everyone, >>> I have been trying for a long time to place a serial signal on one track >>> of an audio recording which I can read afterwards. To make all kinds of >>> things happen at the same time as the audio is played. I have now tried to >>> do this with the old modem system ( TCM3105) but it failed hopelessly. I >>> read that there are also systems to do this using PWM. Does anyone have an >>> idea? >>> regards >>> Hans >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "jallib" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to jallib+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/773ca37b-9bed-4349-a8eb-32a5d8973df6n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/jallib/773ca37b-9bed-4349-a8eb-32a5d8973df6n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "jallib" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to jallib+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/201142693.752814.1645606718467%40mail.yahoo.com >>> >>> <https://groups.google.com/d/msgid/jallib/201142693.752814.1645606718467%40mail.yahoo.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "jallib" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to jallib+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/d4803c41-505a-4297-81d5-7be0ef06b112n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/jallib/d4803c41-505a-4297-81d5-7be0ef06b112n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "jallib" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to jallib+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/DB6P195MB018301D93CBE73C8A9C74FF0E63D9%40DB6P195MB0183.EURP195.PROD.OUTLOOK.COM >>> >>> <https://groups.google.com/d/msgid/jallib/DB6P195MB018301D93CBE73C8A9C74FF0E63D9%40DB6P195MB0183.EURP195.PROD.OUTLOOK.COM?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "jallib" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to jallib+un...@googlegroups.com. >>> >> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/jallib/1712343432.941652.1645735109957%40mail.yahoo.com >>> >>> <https://groups.google.com/d/msgid/jallib/1712343432.941652.1645735109957%40mail.yahoo.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- You received this message because you are subscribed to the Google Groups "jallib" group. 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