Installation
To build working focuser solution you will need:
- installed arduino IDE http://www.arduino.cc/
- arduino board (project was build using Arduino Nano, however any other can be adapted)
- stepper motor (you need to figure out how to fit motor to the telescope focuser)
- DS1820 temperature sensor (optional)
- manual rotary encoder with push button (optional)
- buzzer (optional)
Driver installation
Get from downloads folder Jolo Focuser setup executable and install on your system. You need to have ASCOM platform installed on your machine (http://ascom-standards.org/) that makes this project available only for Windows family operation systems. No standalone software to control motor is included, so you need any other 3rd party software that is able to control focuser via ASCOM drivers (APT, Maxim, Nebulosity and many, many more). After driver installation you should be able to select Jolo main focuser position from ASCOM focuser selection window. There is also Jolo Focuser 2 setup executable that will install on your system another driver with different signature. This one will be visible in the ASCOM selection box as Jolo aux focuser so you can attach there another focuser that can be used for example to control guiding scope focuser.
Arduino IDE
Get from Arduino website installed for IDE and install it. From downloads folder get Arduino libs zip file and extract it to arduino libraries folder in your system (default one is My documents\Arduino\libraries). Configure arduino IDE, plug in your arduino board and get from downloads page Arduino sketch zip file. Unpack it, load to arduino IDE (project file is named focuser) and program your board. You are done. If you use other than 4 wire stepper motor, or want to connect external devices to other pins, you need to modify the sketch (see sections below).
In Arduino Nano board there is built in USB-RS232 converter, so you do not need another circuit. Some Arduino boards does not have built in UART converter (Arduino Mini) so you will need external one to communicate unless you have RS232 port available in your machine.
Stepper motor
Arduino sketch is by default configured to control 4 wire stepper motor. If you want to use different type motor then you need to change its configuration in the sketch. See http://www.open.com.au/mikem/arduino/AccelStepper library documentation how to configure it. It allows you to connect almost every stepper motor in the world.
Of course you cannot connect stepper motor directly to arduino board (unless you have some tiny tainy stepper device that drains less than 40mA - probably they exist somewhere). You need to build or buy stepper motor controller. Simplest solution is ULN2003 for unipolar driver, or double H bridge (like L293 chip) for bipolar motor. There is a whole bunch of ready to use projects or ready to buy circuits.
Temperature sensor (optional)
Dallas Semiconductor 1-Wire temperature sensor DS1820 is used in the project. If no sensor connected, temperature read and compensation will be disabled, no further configuration is required. Sensor data output is by default connected to arduino board pin 7 - you can configure it easily in the sketch. Take a look into the DS1820 documentation on how to supply this chip with power - it is easy as it is. Sensor needs to be connected to the board on powering up otherwise it will be not detected and will not be available till another power up or reset. There is a nice feature of Arduino Nano board however - you can reset it remotely using DTR line of the build in serial port converter.
Manual rotary encoder (optional)
The model must be equipped with push button. Encoder A and B outputs are connected do board pins 3 and 5, push button to pin 4. Common pin must be connected to the ground. Using encoder you can manually change focuser position. After pressing push button you can change number of steps for each manual adjustments. There are 7 available "speeds": 1, 2, 4, 8, 16, 32, 64, 128 and 255 steps per each encoder click. One may want to use just a few buttons manual controller instead of rotary encoder - no problem at all - just a small modification of the sketch will be required.
Buzzer (optional)
Buzzer is used to indicate following actions:
- driver connection (1 long beep)
- not recognized command (5 short beeps)
- focuser move end (1 short beep)
- push button action (1 short beep = focus mode, 2 short beeps = manual step adjustment mode)
- manual step adjustment (1 to 7 short beeps depending on selected speed)
Buzzer is optional, however I recommend to use it when using manual encoder - it is a great help, because no other indication of mode and selected speed is available.