special WAV player for ham radio

[tf3t]

Hi

Just got the Teensy 4.0 with the rev.d audioboard yesterday -

So - I'm making a small voice keyer for ham radio, so - I got this working - just amazing libraries and code samples etc - that's why I love Teensy !

What I'm actually doing is a text to speech thing. My contest software is limited, and I really want this - so the contest software sends via serial protocol text like TF3T (my callsign) and the Teensy plays out T.wav F.wav 3.wav T.wav ... and those are the NATO phonetics in my voice - recorded, processed and snipped in Audacity ... reads out: "Tango Foxtrot Three Tango"

and I got this working in like 2 hours - still have some serial stuff to do - actually mimicking a Morse keyer that has a well defined serial interface .

but I'm just reading straight from the SD card - and I actually got extra PSRAM from PRJC..

so, as this is a "nice to have" project, that I reeeally did not think I would get working - I'm thinking - is it just ok to read each letter again and again from the SD card ? in a contest I work like 4000 callsigns, average length is 5 letters. so it's like 20k reads.. I would assume compared to GoPro or something working on a SD card is nothing

or is there some "easy" way (reads: you have code that you can show me) to read all the wav/letters into RAM when the Teensy boots up and then use them from the RAM


any hints greatly appreciated

Benni

 

[el_supremo]

is it just ok to read each letter again and again from the SD card ?

Yes. As long as the SD card doesn't lag between each WAV it'll be fine. If it does lag, you could store the audio files on PSRAM and use AudioPlaySerialflashRaw but, as its name implies, it doesn't use WAV file, only RAW files. You'd have to convert the WAV files to RAW.

I don't think the T4.0 has enough RAM to hold 36 or more WAV files - I estimate you'd need about 3MB.

Pete

 

[tf3t]

yes, I'm using about 5Mb for the wav files.. but this actually works very well... so I'm not pausing, and it's very nice to be able just to use the Wav format - so easy to record and change. So for this application the read time from the SD card does not seem to be a factor - but I will stress test this