Vermes
Advanced Member level 4
It is a simple controller for unipolar stepper motors. The electrical system consists of few elements. The most important of those are Atmega8 microcontroller and 4 transistors 2SK2382. A large electrolytic capacitor stabilizes the motor's power supply voltage (it is not necessary, because engines should be powered by constant current rather than constant voltage). In addition, the plate included 4 LEDs indicating operation of keys and one as a power indicator. It is possible to power the engines and microprocessor from the same source (only one condition is that the power supply was greater then 7V). To make this, just close one jumper. The system can also be powered by connecting a separate source of voltage 5V to separate ARK connector or directly from the USB adapter – RS232 (+5V, TxD, RxD, GND). Free 3 MOLEX connectors are used to connect end switches (HOME, END) and the emergency button (E_STOP).
The purpose of this project was to test stepper motors before connecting them to a small milling machine. After mechanical connecting with the construction, it would be possible to precisely control one axis via PC.
The software uP was written in WinAVR and PC was written in VS C# 2010 Express (not ready).
The development of control 3 or more axis can be done. The system should be expanded by additional two I/O lines and communication module with an additional processor should be built.
The CNC milling machine:
Screen of the control panel:
In addition, waveforms of control the keys:
Link to original thread (drafts in attachment) – Sterownik silników krokowych unipolarnych RS232/USB miniCNC