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Miniscribe 8425S Sound Reproduction

jmacz

Well-known member
Thanks for the pointers. The memory in the 85 isn’t enough (need at least 1MB to keep the samples with enough quality) so will have to look into a data chip as well. Will try it first with an Uno I have somewhere and then if it works and is worth spending more time on, I will try with the ATTiny85. At that point will try and generate the sound dynamically rather than via samples.
 

Phipli

Well-known member
Thanks for the pointers. The memory in the 85 isn’t enough (need at least 1MB to keep the samples with enough quality) so will have to look into a data chip as well. Will try it first with an Uno I have somewhere and then if it works and is worth spending more time on, I will try with the ATTiny85. At that point will try and generate the sound dynamically rather than via samples.

Note that you mention using the Uno - the Uno can't do sound as well as the ATTiny85 because the ATTiny85 has special hardware features that allow it to do higher sample rates.

Sadly the component shortage means the ATTiny85s aren't as cheap as they used to be. They used to be about a dollar each on eBay.
 

jmacz

Well-known member

Note that you mention using the Uno - the Uno can't do sound as well as the ATTiny85 because the ATTiny85 has special hardware features that allow it to do higher sample rates.

Sadly the component shortage means the ATTiny85s aren't as cheap as they used to be. They used to be about a dollar each on eBay.
No I meant just get a working setup with the Uno controlling the Adafruit. Then if I think the synthetic reproduction of the miniscribe sounds is fun enough to continue, then look at eliminating the Uno and Adafruit for a simpler and smaller ATTiny85 implementation.

I could of course also just compile my own ZuluScsi firmware to latch the led a bit longer just to test.
 

jmacz

Well-known member
I did get it working using the Arduino but it's just doing a dumb hold on the signal to allow the Adafruit to trigger. The sound generation is actually kinda cool as the Mac is loading and doing its thing. :) but I think the novelty is definitely going to wear off and I don't imagine this is something I will leave on. It was fun putting it together though.

That said, @Phipli your suggestions have intrigued me. Just for fun, going to try miniaturizing this whole thing with an ATTiny85 and an additional memory chip (8K I don't think is going to be enough). Should be fun, thanks for the suggestion!
 

jmacz

Well-known member
This is what I got working last night.


This prototype is done. Although I can design a 3d printed bracket for it so I can mount it inside the Quadra 700, I'm going to stop here with this one. Going to start looking at miniaturization with the ATTiny85 next.
 

jmacz

Well-known member
Got some time to play with this this weekend. I got it working with an ATtiny85 although it took some work. The onboard memory isn't enough so had to utilize additional flash memory and just the IO from that used up 4 pins. 2 pins went to power/ground. 1 pin for the speaker. Still need a pin for the trigger but the remaining pin is the reset which is needed to program the chip. Had to change the fuse to change the reset pin into a normal IO pin but that meant using the high voltage reset for the fuse to switch back in order to be able to program the chip again. Not difficult, just tedious. The module is now a fraction of the size it was. But it came at a cost. The clock on the ATtiny85 is only able to drive 8khz samples and so the audio is really tinny... not as rich and realistic as it was at 44khz or 22khz. Anyhow, it was a fun exercise.
 

aplmak

Well-known member
This is what I got working last night.


This prototype is done. Although I can design a 3d printed bracket for it so I can mount it inside the Quadra 700, I'm going to stop here with this one. Going to start looking at miniaturization with the ATTiny85 next.
I absolutely love this! I had thought of this years ago.. I wanted to see if it was possible to even do it on an X-Profile for the squeaking of an Apple Lisa Widget. There is another product out there you can buy now but it produces mostly generic pc drive clicking.. not the sweet sounds of the Miniscribe 8425S! I’d totally buy a bunch of these if they were produced!!! Great work!
 
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