I've been planning to make a copy lathe that can turn small pieces of wood. I was browsing the internet and came across this site and the motor control.
There are many types of copy lathes online, but I would like to build a lathe whose trajectories could be taught from a model and saved to the Arduino. After this, the machine would be able to turn a piece without modeling.
Has anyone made a similar device?
I wonder about possible interference with the servo analog data in the link?I already built the device according to the link and tested it. It works well on a breadboard.
Honestly the idea in the DroneBot tutorial works, but it’s just a small demo. A feedback-servo is fine on a breadboard, but once you put it on a real copy-lathe with motors and vibration, the analog signal gets noisy and the travel and torque are not enough. The concept is correct, but the hardware isn’t made for an actual wood-turning machine. For a real copy-lathe you’d need proper linear motion and a stronger feedback system.
I would assume this is a non critical application and suggest maybe using a Nano that plugs into your custom circuit board. This will give you better noise protection and reliability. I have been very successful with this approach. I put the RTC, FRAM, and other I/O on that board. I suggest you do not use the PCF 85 series of parts they have a potential latch up problem with the I2C. I switched to the PCA9555 and am very pleased with the results.
The PCA9555 and PCF8574 are both I²C GPIO expanders, but they have different logic levels for output. To make the PCA9555 compatible with a system designed for the PCF8574, you may need to modify the code to reverse the output logic, as the PCA9555 uses a different output configuration. It has a true output not a pseudo output.