This project was built to be a very rough prototype- a friend who runs a recording studio asked me to build something to see how viable such a device could be. I felt it could be put together very affordably, and I already had many of the necessary parts lying around. It was more or less thrown together in a bit of a rush, as I had only a month before moving to Waterloo.
The motion platform is a very simple design based on OpenBuilds style v-wheel gantry plates, with a few 3D printed parts to make certain interconnections easier.
Each axis is driven by a NEMA-17 stepper motor, powered by a Bigtreetech SKR Mini V1.2 driver board running Marlin firmware. This board was ideal for this application due to its use TMC2209 stepper drivers, allowing the motion of the steppers to be very quiet.
The host computer would be situated in the control room, so this necessitated some way of communicating with the driver board over a long distance.
The easiest way to do this was to take advantage of the recording studio’s infastructure. There are already many shielded microphone cables running through the wall to the control room, so I simply wired one of these up to the TX and RX pins of the SKR MINI. On the control room side, I used a FTDI breakout board to create a USB-serial interface with the host computer.
My intention was to code a simple host application in python to run on PC, but I ended up running out of time.
The gantry plates were machined out of sheet aluminum on my DIY benchtop CNC router, and the 3D printed parts were printed on my home-built mk2 clone.
The most obvious weakness in the design is that the further the microphone extends on the z-axis, the less rigid the setup is and the microphone will tend to droop. This isn’t too much of an issue though, as there is rarely a need for more than about 10 inches of motion on that axis. The XY positioning is fairly stable due to the use of dual leadscrews on the Y-Axis.
I was also anticipating there to be potential issues with electrical noise coming from the stepper motors and their wiring, but this luckily ended up being a non-issue.