Audio Stimulation

MarcoC

Hello everybody, sorry to bother once again!

I'm currently working on the development of a task that introduces auditory stimulation in our usual olfactory-only task.
To implement this, I was considering using piezo speakers paired with amplifiers, triggered by an arduino (that generates our waves too). The arduino would be then access via ethernet serial communication through the state machine.
Is this strategy valid in your opinion?

The only inconvenience is that we currently only have 1 Bpod Shield and it seems to me that generic arduino shields for the Uno won't work properly when interfaced with the state machine.

What's your suggestion on the topic? What would be the best possible choice (good sound quality, cheap and rapidly assembled) to implement simple auditory stimuli in my task?

Thank you in advance!
Have a great day,
Marco

Josh

Hello Marco,

Arduino Uno is an 8-bit board, and our Arduino shield is only compatible with 32-bit boards. All 32-bit Arduino boards have a native USB connection in addition to a separate hardware serial (UART) on pins 0+1.

If you want a low-cost audio system, one option is Teensy 3.2 + the Teensy audio board + the Bpod Teensy Shield. Load this firmware to the Teensy board, and control it in MATLAB with this class. Bytes from the state machine indicate which sound to play, and byte 255 stops any ongoing sound.

Of course, there's always the HiFi module if you need a more premium audio solution with ultra-low latency and low distortion across the rodent hearing range.

-Josh

Melissa_ovo

Josh
Hello Josh,

I'm just wondering does this solution still work right now for Teensy 4.0 or 4.1 (and is there a recommended version between these two)? The info on the website is still says that Teensy shield is only compatible with Teensy 3.x, but I also saw another thread saying 4.0/4.1 is also fine. Has anyone tested this for sound play specifically?
Also, if we are planning to play on four different speakers, is it better to use seperate teensy boards for each which occupies four module ports, or try to connect a set of two stero speakers to a board and seperate left and right track so that they only occupy two ports?

Thank you!!

Melissa_ovo

Josh Or is it possible to connect four speakers to the analog output module?

MarcoC

Josh wrote[quote='Josh' pid='3980' dateline='1635828857']
Hello Marco,

Arduino Uno is an 8-bit board, and our Arduino shield is only compatible with 32-bit boards. All 32-bit Arduino boards have a native USB connection in addition to a separate hardware serial (UART) on pins 0+1.

If you want a low-cost audio system, one option is Teensy 3.2 + the Teensy audio board + the Bpod Teensy Shield. Load this firmware to the Teensy board, and control it in MATLAB with this class. Bytes from the state machine indicate which sound to play, and byte 255 stops any ongoing sound.

Of course, there's always the HiFi module if you need a more premium audio solution with ultra-low latency and low distortion across the rodent hearing range.

-Josh

Thank you Josh!

Josh

Hi Melissa,

It is possible to connect four speakers to the analog output module, keeping in mind that while it is not an audio DAC, the sound quality may be suitable for certain applications.

Each Teensy audio shield only has two channels, and if two Teensies are triggered simultaneously by the state machine, the timing of audio playback start may have jitter as it depends on microSD card access. If all four channels need to be started simultaneously, I wouldn't use this option.

-Josh

Melissa_ovo

Josh Thanks Josh! Just two more things to clarify -
I read on Bpod Wiki that AudioPlayer Serial Interface allows you to "play mono or stereo sounds using Ch1 + Ch2 of the analog output module." Does this mean each BNC output supports one mono sound, and you need to somehow connect two BNC channels to a stereo speaker to play stereo sound?
And also, has anyone tested Teensy 4.0/4.1 compatibility for sound play?

Josh

Hello Melissa,

To play on 4 channels simultaneously you'd need to use WavePlayer firmware. You'd control the device with the BpodWavePlayer interface. More info on swapping firmware is given here.

I tested 4.0 with Teensy Audio for 4.0 and the Bpod Teensy Shield. It works, but you'll get better latency, onset jitter and data transfer speed with the Analog Output Module or HiFi module.

-Josh