Designing a keyboard with MIDI interface on Daisy seed?

Hello everyone, I am new with Daisy so I need your help to figure out which things I need for this design (or maybe if you recommend not to use Daisy for this)

So the device I will design is something similar to

-You turn it ON, and it will read sound files from an external memory. It will complete all the music notes that are not in those files by editing the other sound frequency

I think it will need to have a big RAM memory to store those sounds (is it possible for Daysi seed to upgrade RAM for this?)

-Then it will have a MIDI interface to connect a MIDI keyboard, to activate the sounds when a note is pressed

So tell me id this is possible on Daysi seed , or if you know about a similar project. I know there is Daisy Pod that could be more “ready to use” for my project, but it is a bit out of my budget

Thanks, and please tell me if you understood what I wrote (not native English) I will happily edit it for you to understand

Quite possible to do this on the Seed. You won’t get 128 note polyphony but hardly a problem on a 2 octave keyboard :slight_smile: Do you want to use USB or DIN MIDI ? And obviously less sounds stored on the Seed but the SDRAM is more than large enough for something decent.

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Thanks for your response

A polyphony of 4-6 would be perfect, but I am concerned about the delay and the quality of the output sound. Do you know how much miliseconds of delay and bits would I get?

I would prefer DIN MIDI, but that’s not very important. Why do you ask?

I looked again and just read that has 64Mb of SDRAM, I think that is enough for any 2-octaves sample

Other thing that I would like to do is to put a screen on the device, to read the name of the instruments. Is that possible on Daysi Seed? I saw a project (Pollen 8) that only used led lights to “comunicate” with the user

Probably best to use 16 bits per sample to reduce storage. Delay depends on what block size you use to drive the DAC. But you will be able to get high quality sample playback with no noticeable lag. I don’t actually think the number of notes in polyphony should be an issue - each keypress just triggers a new counter to increment through the wave and sum the results. Simplest way may be to have 128 counters so you aren’t assigning them dynamically to different notes. Sum the lookup results from all of them all the time. But if doing this make sure the first sample is zero to avoid any DC build-up.

DIN MIDI (a) works and (b) uses less processor cycles.

You can add a simple LCD screen on the SPI bus - the 2.4" ones work well.

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Do you know if there is documentation about this in Electrosmith? I want to know more about possible lag, it is one the main issues that I want to measure (I have only found “12-bit Digital to Analog Converters(x2)” on the page)
Or could you tell me more about it? It is possible to estimate the delay?

Thanks for your response, you are very helpful

The 12-bit DACs are not used for audio. There is an external codec for audio in and out.

Latency is discussed here:

Of course, there is also a small delay added by transmitting the MIDI message, that is true for all MIDI devices.

In my opinion, you should just build samplerbox.

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Thanks for your response

?? what are they used for?

Do you mean about this “High fidelity AKM stereo audio codec with up to 24-bit 192kHz,” (from Daysi seed page) ? Isn’t there a pdf with all specifications and data about Daysi Seed?

Cool, they measured it with a scope. Great post

Do you know how many ms?


I mean no insult, but it seems to me that you know nothing about how to implement a sample player. You won’t learn how by asking endless questions.

DIN MIDI takes about 1ms to transport a 3 byte message. MIDI running status reduces this by one byte when possible.

I am studying Electronic Engineering (almost finished), but yeah, I am quite new to this stuff. I am trying to start this project in my university to learn about it. I have professors’ help and everything, but they don’t know much about Daysi Seed

Sorry for newbie questions, but I need something just to start of

Another reasonable suggestion would be to forget about creating a sample player at first. Buy a Daisy Seed, wire up a MIDI input and some audio outputs, and start learning from the example programs. Details are in the Daisy Pod schematics.