Possiblity of using Moppy2 for a 56K modem

[DB4000K]

Is there any way I can use moppy2 to play higher pitched or lead melodies on the 56k modem speaker, or with the built in dial tones via serial connection?

Also, how do you connect HDD's to Moppy?

[samphonic]

Is there any way I can use moppy2 to play higher pitched or lead melodies on the 56k modem speaker

Yes. The "how" might be a bit involved though 😜. Because the STEP pins are essentially outputting square waves, you could theoretically just connect them directly to the speaker (possibly via some sort of amp) and drive the speaker directly. Trying to do anything via serial would probably be difficult as you'd need to basically emulate the modem drivers in your Arduino code.

or with the built in dial tones via serial connection?

Same as above for any sort of serial connection, but also the touch tones (different than dial tones, but who uses phones these days, haha) are all pairs of frequencies (each number is a pair) so unless you were playing very specific, discordant melodies they wouldn't really be of any use.

how do you connect HDD's to Moppy?

HDDs are also connected physically rather than via data connections by connecting to the coil (possibly via an amplifying circuit) on the read head. The coil is in a magnetic field and acts basically like a speaker to reproduce the frequencies being input.

Floppy drives are fairly unique in having their stepper motor controls essentially directly exposed via the STEP and DIR pins on the back, whereas more modern hardware (HDDs, printers, scanners, etc.) have some sort of abstraction between the data cable and the motors.

[DB4000K]

ah okay, gotcha. so i can solder to the speaker. maybe i can figure some other stuff out too with it. i have a few scanners i would love to try with this

[DJthefirst]

Also if you want to player higher notes with Moppy they will become increasingly out of tune. On a suggestion someone on my discord was able to use a dedicated timer to improve the resolution but as a result you only get a single instrument per microcontroller. (They ported it to their Moppy version)

[samphonic]

higher notes with Moppy they will become increasingly out of tune

Ah, also a good point. If you're using an ESP32 you could try using PWM as well and that might get you some fairly in-tune higher notes (honestly if I ever get around to revamping Moppy, might switch to ESP32 and just use PWM by default actually)

[DJthefirst]

The person on my discord says they were able to hit 0.1 us on an uno though I haven't validated it myself. I suggested using a single timer and sent them this article but they implemented it. https://forum.arduino.cc/t/highest-frequency-using-arduino-timers/1053104/12

I also asked and they sent their code which is for Moppy but I'm not on my computer atm so it might be a bit before I can send it. I might also ask them if they want to make a merge request if it does not disrupt the code too much.

As for PWM on an esp32 I am not using it in my current version which only gets down to 8us which is much better than the default 40us but still off by a few cents on high pitched stepper motors. Now that you brought it up I will look into it more when I have time but I originally thought the Esp32 shared a common base freq across its PWM channels but it looks like that's not the case...

[DB4000K]

I currently have four 56k Modems connected to my arduino. This was all supposed to be a test LOL! I am trying to work with serial connections. These modems are all pretty basic US Robotics and Zoom Modem. Currently testing on Arduino MEGA but might try an ESP board later and write up some own code for these modems. On the mega, I can generate DTMF tones by sending AT commands from my Arduino Mega to a 56k modem. I’m using a MAX232 to convert the Arduino’s 5V TTL serial to proper RS-232 levels for the modem. Once the modem is in command mode. I know most of the modems I have will support AT commands. I have two flatbed scanners I am also working on tracing the motor driver pins cleanly. It’s definitely more of a challenge than floppies since everything’s engrossed behind the onboard controller chips, but if I can tap into the stepper control lines cleanly, it should be doable. ESP32 PWM could be the way to go for sharper notes. definitely worth a try. Let me know if you share that code.