Mic sensor on CM-550

@willson @Andrew
I want to be able to detect the beat of music so that I can make my robot move with the beat and also change the color of his chest LED’s from blue to red with the music.

I have been unable to find out how to get sound level reading from the built in mic, it seems to only have recognize really load claps.

I did manage to connect an external mic to 1 of the ollo ports and use the ADC to read it although it needed a voltage splitter because because the power supply of the ollo is 5v but the ADC input is 3.3v. see my video here https://youtu.be/NjI_BYqcQ8Y

I would much rather be able to use the built in mic rather than having to build and add extra external stuff.

Is the a way to be able to read the internal MIC ???


Our engineer confirmed that the MIC cannot be used as an analog input device as it is connected to one of MCU pins that cannot be configured as an ADC input.

If your mic doesn’t require more than 0.5A to operate, you may use one of OUT1 or OUT2 pin of 5Pin channel 1 or 2 to get 3.3V power source as described in the eManual.

Hope this helps you to reduce the complexity of the hardware design.

Thank you.

@willson thanks for your reply

I tried to power the mic by 1 of out pins on the same port, when I set the out pin to high it will power the mic fine but as soon as you set the Analog pin on the same port as an input it then sets all the other out pins to low and stops powering the mic. So it is not possible to set an out pin to high and read the ADC pin at the same time. Maybe this can be fixed on future firmware updates for the CM-550

In the end a voltage divider isn’t a difficult work around to step from 5v down to 3.3v for any peripheral I want to connect to an OLLO port. What is more of a design complexity is the fact you can’t use the on board mic as to detect sound level and you have to wire on a second mic.