Picomite

[JKnightandKARR]

I've got links to the PPDB and PDB, now I measured the Raspberry Pi Pico and got 3.3v on the output, now what I need is, how can I modify the audio amp on the PDB to work better on 3.3v , not to mention putting the 2 audio ch into 1 ch or should I try the circuit on the PPDB even though I am using an ext speaker? The Picomite manual, on pg 35 shows a low-passfilter, that shouldn't be an issue using SMD right off the pins, but its the amplifier I'll need some help with.

Well, the amplifier on the PPDB is stereo. It is designed to use headphones.

I didn't find any filter circuit on page 35. In your last link, I did find one on page 49, for which the output could be connected to external stereo amplifier speaker systems, such as computer speakers, which can be obtained cheap, like these.

That's it, diff doc, so I might wanna download it so I got it... Anyhow, that shouldn't be hard on either todo, but I need a single speaker, for my voice display.

[Chris Savage]

That's it, diff doc, so I might wanna download it so I got it... Anyhow, that shouldn't be hard on either todo, but I need a single speaker, for my voice display.

Well, you don't need to use both channels. You could minimize circuitry and ignore a whole channel. On Arduino projects, I have often used one channel, because some of the lesser expensive MP3 Player boards and amplifier boards only have one channel. In that case I can make a mono MP3 and save space there as well.

[JKnightandKARR]

That's it, diff doc, so I might wanna download it so I got it... Anyhow, that shouldn't be hard on either todo, but I need a single speaker, for my voice display.

Well, you don't need to use both channels. You could minimize circuitry and ignore a whole channel. On Arduino projects, I have often used one channel, because some of the lesser expensive MP3 Player boards and amplifier boards only have one channel. In that case I can make a mono MP3 and save space there as well.

it's for DTMF tones, so I'll need both.

[Chris Savage]

it's for DTMF tones, so I'll need both.

Is this a limitation of the PicoMite? I'm asking because the lowly BASIC Stamp 2 can generate DTMF tones using a single I/O pin. Two channels aren't necessary to create a DTMF tone, unless the MCU is incapable of doing it without two channels.

At the same time, DTMF tones can be recorded and played back just like any other sound; again, with a single channel.

[JKnightandKARR]

it's for DTMF tones, so I'll need both.

Is this a limitation of the PicoMite? I'm asking because the lowly BASIC Stamp 2 can generate DTMF tones using a single I/O pin. Two channels aren't necessary to create a DTMF tone, unless the MCU is incapable of doing it without two channels.

At the same time, DTMF tones can be recorded and played back just like any other sound; again, with a single channel.

Yes, it requires both ch to make 1 duel tone, and what I want todo is match the tones in the show and the timing and not have the extra background noise, such as engine, or what not.  If it was just for me, I'd just use the BS2, sadly, it's something at some point I want to try and sell.

[Chris Savage]

Yes, it requires both ch to make 1 duel tone, and what I want todo is match the tones in the show and the timing and not have the extra background noise, such as engine, or what not.  If it was just for me, I'd just use the BS2, sadly, it's something at some point I want to try and sell.

I'll be honest, I'm shocked that's the case. Nonetheless, you can still mix two channels. In the schematic on page 49, remove one of the 22nF caps and tie the two outputs together after the 680Ω resistors on the right. I still think I would record the tones as WAV / MP3 files and play them back as samples, but that's just me.

[JKnightandKARR]

Yes, it requires both ch to make 1 duel tone, and what I want todo is match the tones in the show and the timing and not have the extra background noise, such as engine, or what not.  If it was just for me, I'd just use the BS2, sadly, it's something at some point I want to try and sell.

I'll be honest, I'm shocked that's the case. Nonetheless, you can still mix two channels. In the schematic on page 49, remove one of the 22nF caps and tie the two outputs together after the 680Ω resistors on the right. I still think I would record the tones as WAV / MP3 files and play them back as samples, but that's just me.

I'll consider that, but I do have other buttons to hook up and might have them random DTMF tones, which I can just create a bus of somekind to connect to.  Meantime, looks like the PDB used Op Amp I think and the chip on the PPDB is obsolete, but there are other similar options available. Haver to breakout my books from school on figuring out voltages on Op Amps. Thanks for the help.

[Chris Savage]

I'll consider that, but I do have other buttons to hook up and might have them random DTMF tones, which I can just create a bus of somekind to connect to.  Meantime, looks like the PDB used Op Amp I think and the chip on the PPDB is obsolete, but there are other similar options available. Haver to breakout my books from school on figuring out voltages on Op Amps. Thanks for the help.

Well, if you use the schematic on page 49, you can simply run that output into an LM386 amplifier using the reference schematic in the datasheet.

[JKnightandKARR]

I'll consider that, but I do have other buttons to hook up and might have them random DTMF tones, which I can just create a bus of somekind to connect to.  Meantime, looks like the PDB used Op Amp I think and the chip on the PPDB is obsolete, but there are other similar options available. Haver to breakout my books from school on figuring out voltages on Op Amps. Thanks for the help.

Well, if you use the schematic on page 49, you can simply run that output into an LM386 amplifier using the reference schematic in the datasheet.

That shouldn't be too hard. I think you said before that the bs circuit needs optimized for 3.3 so that shouldn't be too hard.

[Chris Savage]

That shouldn't be too hard. I think you said before that the bs circuit needs optimized for 3.3 so that shouldn't be too hard.

Actually, the supply voltage for the LM386 can be 4V–12V or 5V–18V, depending on the version of the IC. The supply voltage on this IC has nothing to do with the input voltage of the audio signal.

EDIT: Use the reference schematic in the datasheet for the LM386, not the schematic for the PPDB. The extra circuitry you need is already a part of the circuit on page 49 we talked about. Remember, the LM386 can be set between 20 and 200 gain.