I implemented the UHU Servo Controller 3.00 on the Atmel ATtiny2313, with the goal to provide an affordable alternative to commercial servo products. It is the ideal base for DIY servo projects.

Its focus is easy integrability and a simple user interface which can be used to parametrize the servo loop for a wide spectrum of applications.
The controller is based on an extended PID algorithm, where in addition to the common proportional, integral and differential loop parameters a higher order feedback is employed to stabilize the system without negative influence on the tracking error.

The connection to the PC based CNC application is the widespread step/dir interface plugged on the PC parallel port.

The controller can be parametrized from the PC by serial communication and plain text dialogue.
All loop parameters can be stored in the built in EEPROM which is secured by a forward error correction algortihm. Multiple sets of parameters allow the usage in different applications just by switching to another optimized setup.

If the special terminal program is used, the tracking error can be displayed online like on an oscilloscope. This ensures a best possible tuning of the servo loop.

The motor power can be switched off if an adjustable tracking error value is exceeded. An error input allows to shut off other axes if one system runs in an error.

An internal watchdog shuts down the power stages if for any reason the recalculation loop is not jumped in for more than 125ms.

The controller makes easily over 150.000 steps/s (4-fold interpreted encoder lines).
All inputs are handled as hardware interrups.

The english version makes use of english commands as shown in the manual.
The controller is not distributed on a commercial base. Due to an overwhelming interrest I decided to ship the controller in a special licence model. I call it 'BeerWare'.
Whoever wants to get his hands on one of them, sends me the money I have to pay for the parts and a bottle of his best local beer. This can be substituted by useful tools or really hot sauces and hot and spicy snacks.
Read more in the '
instruction leaflet'
Kontakt: uli@uhu-servo.de