An ASCOM/RoboFocus protocol compatible focuser driver for unipolar
a Hurst stepper motor in spare, I built the stepper motor controller
circuit from www.vimms.org and
rewrote the firmware (Atmel AT90S2313) to mimicry a RoboFocus controller
(without temperature compensation). I also added to buttons to allow
manual control of the focuser.
Standalone operation using built-in buttons, running the motor
at slow or high speed.
- (Nonlinear) acceleration ramping
- Half step – high torque stepping
- All parameters are permanently stored in EEPROM
- RoboFocus compatible protocol – to control the focuser
use the free downloadable “RoboFocus Control Program” (RFCP)
which is ASCOM compatible and supports ActiveX scripting
- Simple and cheap to build
SBIG DC/DC 12V Converter
A cheap, simple,
small, secure and lightweight DC/DC converter for SBIG ST7/8/9/10/2000
This small circuit delivers +12V (direct connection), -12V (125mA)
and +5V (3000mA) which are necessary to drive a SBIG ST-X series CCD
camera and also supports safety protection like inverse polarity, overload,
overcurrent or short circuits. To avoid any noise from other devices,
the input is filtered with some caps, totalling in 1600µF.
circuit is from Takashi
Ohta, Japan but I used other
parts which were available in Austria.
Total cost: ~70.00 €
This replacement for the original Losmandy controller contains:
- Boxdörfer MTS3-SDI with
- LC Display
- Encoder IC with separate 5 Volts supply and DB-9 connector
- Handbox/Autoguider RJ11 connector
- External MTS Port
- USB-RS232 converter
- 12 to 24V converter (for MTS3-SDI)
- USB 4-port hub
- USB 2-port hub + RS232 converter
Because of the vast number of cables between those items I just put
them together in a Tupperware box, and mounted it to the Losmandy G-11.
Finally, the number of cable connections have been drastically reduced.
I also plan to put the Focuser circuit and the SBIG DC/DC converter
into a new and better built version of this box.