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FarmBot - Accelerated

A project log for FarmBot - Open-Source CNC Farming

FarmBot is an open-source CNC farming machine and software package built for small scale, hyper local, DIY food production.

rory-aronsonRory Aronson 08/28/2014 at 20:360 Comments

One of our project's software contributors, Tim Evers, just updated the Raspberry Pi and Arduino codebases for FarmBot to support acceleration! Before these updates, FarmBot performed very abrupt movements because the software would drive the motors from standing to full speed and back to standing in an instant; there was no smooth acceleration function built in.

Now, the motors are ramped up to full speed and back down over a period of time. This is especially important for FarmBot because the motors are relatively small (NEMA 17) for the size and mass of the FarmBot gantry system. Before the update, the stepper motors would occasionally "miss steps" meaning that the microcontroller told the motor to turn, but there was too much opposing torque and so it did not in fact move as expected. This creates a situation where the microcontroller thinks FarmBot is in one location, when it is actually somewhere else. Subsequent movements could cause wasted water, damage to the machine, or the destruction of the plants - all bad!

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