arduino tap tempo for pt2399 ?

[carlozsulca]

Hello, I recently made a thread asking for recommendations on delays with the pt2399, I was putting together one that I liked but I wanted to add a tap tempo, well I investigated and they always use specialized chips, I live from Peru, here it is very difficult to get those chips so idee in a tap tempo made with an arduino nano and a DAC, the idea is for the arduino to control the tap tempo and send a signal to the dac and it makes a voltage change and goes to a led that controls an ldr, it's something Simple in my opinion, if anyone has any idea which transistor could go, it would be better I think, I also put a switch to vary between the tap tempo and the speed potentiometer.
the bad part is that I am not an arduino programming scholar, I hope someone from here can support that, I suppose it would be to edit a tap tempo code that already exists and add the voltage control of the DAC, here is the idea and schematic, anyway I will try to make the code, maybe it will take me a few months, I will publish it if I get it
-The position of the switch is wrong but I did not find the way to change it

[Ripthorn]

I've posted a project on my website about doing exactly this using an Attiny85 for the tap functionality. It's based on the tap tempo scheme I've used on several other projects. It should work, though I've not built this standalone yet. It's pretty straightforward and I have schematic, code, etc. All available for free. https://scientificguitarist.wixsite.com/home/pt2399-tap-tempo

[iainpunk]

why would you use an external DAC if you can just program PWM to control the LED!

cheers, Iain

[carlozsulca]

I've posted a project on my website about doing exactly this using an Attiny85 for the tap functionality. It's based on the tap tempo scheme I've used on several other projects. It should work, though I've not built this standalone yet. It's pretty straightforward and I have schematic, code, etc. All available for free. https://scientificguitarist.wixsite.com/home/pt2399-tap-tempo

Thanks for the link, great project by the way, I will try to get the Attiny85 and I will, perhaps the only thing that comes against is the complexity of the circuit, instead in the idea that I present, it is only to solder the atmega in smd and dac They take up very little space and the entire delay pcb could fit in a 1590b
can even generate waves with the dac and thus obtain a kind of vibrato

[ElectricDruid]

why would you use an external DAC if you can just program PWM to control the LED!

Yes, my thoughts exactly! I'm not familiar with the AVR/Arduinos but I bet you've got 10-bit PWM output, and maybe even better. That's loads for something like this (examples that use digipots only have 8-bit resolution, for example).

Perhaps more important is feedback from the PT2399's pin 5 clock output back to the Arduino so it can measure what delay length it has set. Otherwise you'll have to do some kind of "manual" calibration step.

[carlozsulca]

I've posted a project on my website about doing exactly this using an Attiny85 for the tap functionality. It's based on the tap tempo scheme I've used on several other projects. It should work, though I've not built this standalone yet. It's pretty straightforward and I have schematic, code, etc. All available for free. https://scientificguitarist.wixsite.com/home/pt2399-tap-tempo

Hello, I made all preparations to make the delay, tomorrow I will go to the electronics store, I had a query, the encoder switch must be 20 or 24 positions?

[Ben N]

Apologies for digging up zombies, but I just came across Brian's project, and it looks like a great add-on, even for one of those super-cheap PT2399 modules on Aliexpress, etc. Kudos!
One question: Brian, what about Tom's point re. pin 5 feedback/calibration?
Edit, a couple more questions:
As to the ATTiny85, 10mhz or 20mhz make a difference?
And - I can't open the schematic (png) on the Github site, is is the same as the one on your Wix page?
And - any more info on the rotary encoder, so I know what to order?
TIA

[Ripthorn]

Hi Ben, encoder is any EC11 with switch. I typically run the attiny at 8 Mhz internal. I didn't do any pin 5 calibration, but the encoder will adjust relative to the trapped in time in small increments (2 or 4 ms, I think, I don't recall of hand). Schematic on github is the same a on the web page. After in home from vacation at the end of the week, I'll try to see about getting that fixed. I have used this module on a few different projects, such as the EchoWreck, but I haven't built it completely standalone yet, as it's always just been an integrated part of the circuit I was building. Feel free to provide any feedback.