Roz is currently built with 16 AX-12 servos, a bunch of bioloid brackets, a lot of 3D printed parts, and a mix of off-the-shelf and custom made hardware & components. For sensing, Roz has five VL53L1X laser time-of-flight range finder sensors, an MPU-9250 based IMU, and a downward-facing Optical Flow sensor. Roz also has a camera in the nose, hooked up to a Raspberry pi zero w board.
The sensors (except the camera) are controlled by an ARM Cortex M4 board running MicroPython. This board is set up as a Bioloid device on the servo bus, so I can access all the sensors over the bus from the raspberry pi. Roz also has a custom power management board that has an ARM Cortex M4 chip on it, also running MicroPython. This is also on the bus, and manages switching from wall power to the 3S Lipo battery seamlessly.
You can see some videos of Roz (including much earlier ones) on my YouTube Channel, like this one:
Roz when standing actually has 90mm of clearance under the head, which is where the sensor is. Right now I'm not using that sensor, because it takes a long time to get the data using the API I have in Micro Python (it varies, but sometimes upwards of 500ms). I have to take a much closer look at it to see what is happening. Right now the I think the head board has about 10ms free after hitting all the TOF sensors and the IMU, when I'm running it at 50Hz.