CV in for parameter sweep

I would like to control a parameter sweep of a sound through the Shruthi’s CV input. I was thinking I could send an analog output from Arduino, which is 0 - 5V PWM into one of the CV ins. I’m just not exactly sure how to do it. CV1 already has a connection coming from the Controller Board. Do I run a wire in between the controller board and the filter board? Do I also need to run a connection to ground? My idea is to use the Arduino to manage data coming from external sensors and then send CV out to the Shruthi.

It’s the digital board that processes the CV in, not the filter board (if you look at the latest board revision, there’s no hole/pins for the CV ins, to make it clear).

You need to run a cable from the filtered arduino output to the Shruthi-1 CV-in, and another cable to connect the ground of the Shruthi and the Arduino.

Yes, there needs to be a filter between the arduino PWM output and the Shruthi-1, as simple as a lowpass RC network with a cutoff of 1kHz (eg 22k / 10nF).

Thanks Pichnettes! Will I need to modify the firmware to make this work? I looked at the signal flow documentation in the manual, but I didn’t fully understand how it works.

You don’t need to modify the firmware as long as you’re fine with having your CV input being made available as a modulation source in the mod matrix.

Just use the Modulation Matrix, choose a Slot, select CV1…4 as Source and anything you like as Destination and set the amount to something other than 0 (try 63 for max effect.). Its really that simple, try with a Pot…

Ok, I think I understand how this works. I have a question about the CV inputs on the controller board though. My board (v0.7), has a section labeled “Input Expansion” with IN1, IN2, IN3, and IN4. Below that are CV1 and CV2. I should be using the IN1, IN2, IN3, IN4 for my CV ins? Are the CV1 and CV2 just redundant? As far as the Filter Board goes, I have an 8-pin connector between the controller and filter boards, so there are no pins going to the filter board from IN1, IN2, IN3, IN4. I’m assuming this is fine, correct?

The filter board doesn’t do anything with the inputs 1 to 4.

CV1 / CV2 are outputs.