Recording and repeating voltages

[darren adcock]

Hi all. I've been trying to research how to record and repeat sequences of voltages to no avail.

What I want to be able to do is; use piezo discs and a signal conditioning circuit (courtesy of you guys a while back) to pick up vibrations from an area. then have a way of recording these and be able to repeat them in exactly the same way

I use the sensors to modulate parts of my synthesizer. However with the growth of my synth it's getting less feasible to take it to the field. So being able to record and repeat would be a huge help.

Thanks in advance

Darren

 

[Alec_t]

That's a job for a MCU. Condition the signals to be within the allowed analogue input range of the MCU, use an A-to-D converter in the MCU to get digital values, store the digital values for later conversion back to analoge by a D-to-A converter. Can you program an MCU?

 

[kellys_eye]

DAQ - Digital Acquisition. There are some projects around that offer analog/digital recording onto SD card in multi-channel ways but there are limitations in every system based on sample rate and length of recording although, theoretically, you could do this ad infinitum.

In a most basic form you could use those digital voice record/playback modules for short sample periods but without knowing your full spec requirement we can't be more specific.

 

[darren adcock]

HI folks I've never used a microcontroller or programmed one. I have however done quite a lot of coding in my past.

However I have no idea how to interface with a microcontroller even if i could write a programme for it... I have an arduino Kit somewhere which i've never looked at.... maybe this is the time to open that up

Full spec:

I'll try to address this here

Control voltage range is nearabouts -8v to +8v.... it's meant to be 5 either side but I've not ran into problems yet.

length of recording..... I think I'd like up to 20 mins for now... but to be honest even a minute would be a huge help

It would need to run also from a portable power source... at the minute I have AA batteries, which is rubbish..... but upgrading to LIPO soon


Thanks for replies and I'll follow your leads

Best

Darren

 

[Harald Kapp]

Recording and repeating a sequence of voltages is everyday business in music.

Any audio recorder can record the signals as long as the frequency is within the audio range and the amplitude is scaled to match the input range of the recorder.
The audio can be played back to reconstruct the sequence of voltages and these can be amplified to (almost) any level required.

Use for example the soundcard input/output of your PC. Use your smartphone if it needs to be portable. Plus an amplifier for the +-8 V amplitude required.

 

[Alec_t]

Use for example the soundcard input/output of your PC.

Be aware that sound cards may have a frequency response that drops sharply below about 20Hz.

 

[darren adcock]

Ahhhhhh thanks Harald. I can even begin work on this tomorrow.

Cheers

Darren

 

[Harald Kapp]

Be aware that sound cards may have a frequency response that drops sharply below about 20Hz.

That surely is a limitation to be taken into account, as well as the frequency response above 15 kHz ... 20 kHz.

 

[darren adcock]

I can use my field recorder ( it has 4 tracks) and auto levels function which i've used a lot with piezo discs.

 

[Harald Kapp]

You may want to turn off the auto level function to better record the varying levels of voltage from the piezo sensors.

 

[darren adcock]

Ok, Cheers Harald.