set tone frequency?

tth

Hi all,

Does anyone know if there is a way to specify a specific frequency for a tone for a buzzer to play? like you can in an arduino script?

thanks!

Josh

Which buzzer are you using, and which device is controlling it?

th2

Josh wrote[quote='Josh' pid='1264' dateline='1575514394']
Which buzzer are you using, and which device is controlling it?

Hey Josh,

Basically I have tried many different types of buzzers and speakers, which I have confirmed can do high frequencies when not using bpod, and I am using a state machine r2.

Basically my goal is to play either 1) a sweep of tones from _~4,000-24,000, or if I can't do that, 2) multiple distinct tones in that range.

The issue I am having is that it seems that I am maxing out through bpod at around 5000 hz frequency, anything above that sounds the same. Matlab can play much higher frequency sounds through speakers on the computer itself, so it isn't rate limited by matlab, the speakers can also play higher frequencies, so I can only conclude that bpod has some kind of rate limiting issue? Or the script for bpod?

Alternatively, I could just play a recorded sound, or matlab converted sound, instead of frequencies of buzzers, but when I try to play sounds with normal matlab commands in the bpod script, i get errors and it wont let me. and from searching on the forum it seems like that doesnt work?

My current method that works only up to 5000 hz is using a global timer to output ttls to my buzzer like this:

sma = SetGlobalTimer(sma, 'TimerID', 2, 'Duration', 0.0000001, 'OnsetDelay', 0,...

'Channel', 'BNC1', 'OnLevel', 1, 'OffLevel', 0,...

'Loop', 1, 'SendGlobalTimerEvents', 0, 'LoopInterval', 1/5000) %1/hz frequency of tone

But is there any easy scripting solution you can help me with to get to higher frequency tones, or is it a physical limitation of the bpod box??

I have seen in some other threads there are some audioplayer, teensy, psychtoolbox etc and things, but i get an error with psychtoolbox, and it is very unclear to me what hardware i need in order to use those other ones...

and i dont see why i shouldnt be able to do higher than 5000 hz using the state machine and matlab? very minimally simply just playing a recorded matlab sound?

any help would be greatly appreciated, and please let me know if i specifically do need to order other parts so I can do so asap.

thanks!

Josh

Hi TH2,

The state machine steps through time at 10kHz (100 microsecond updates) - so you can't set a state timer or global timer with a period of less than 100µs.

A premium solution for audio playback with Bpod is available from the hardware platform at CCU. You can contact them using the Email on this page.

A lower quality option (but still higher quality than toggling a state machine digital output!) is to use our analog output module with this adapter. You can define analog waveforms in MATLAB for playback with a 96kHz sampling rate - which should give you a fair waveform at 24kHz. However, unlike a true audio DAC, the analog output module's output is driven by a general purpose voltage DAC (i.e. an NI card analog output) - so you will have aliasing and other minor audible impurities in the waveforms. If you're going to go this route, we have special audio firmware (upload instructions here) and an audio MATLAB class to simplify sound playback.

-Josh