4 module to be installed. Module with 4GB of RAM is recommended.
AstroLink 4 Pi has been designed to work under the control of the dedicated AstroLink 4 Pi INDI driver, which
is available at https://github.com/astrojolo/astrolink4pi . Astroberry system is recommended, however any
working Linux distribution that supports INDI drivers system will work. Good quality 32GB or larger card is
recommended (Class 10 at least). Most of the Raspberry Pi *problems come from a poor quality power
supply or SD card.
PWM outputs
AstroLink 4 Pi has two RCA outputs that provide PWM (pulse width modulation) regulated signal.
Regulations cover the full 0-100% range. These outputs are usually used for powering dew cap heaters.
Output can be regulated using controls in the dedicated INDI driver panel. PWM cycle frequency can be set
in the INDI driver options in the range 10-1000Hz. Default output value at the connection can be defined.
Switchable 12V DC outputs
The device contains two switchable DC outputs, that may provide a supply voltage for imaging setup
components (camera, mount, etc). Output can be switched using controls in the dedicated INDI driver panel.
Default output value at the connection can be defined.
Focusing motors control
The focusing motor can be controlled with AstroLink 4 Pi device. The focusing stepper motor can be
connected to the 6 pins RJ12 socket (see Figure 5). It supports 12V unipolar motors with gearboxes and
bipolar motors at any microstepping resolution in a range of full step to 1/32. The focusing motor can be
controlled with a dedicated INDI driver panel and via the INDI focuser interface. Depending on the AstroLink
4 Pi revision, the stepper motor current is adjusted with a potentiometer, or in the INDI control panel.
Setting holding power is also possible. For unipolar geared motors it is highly recommended to set holding
power to zero, so the motor will not overheat.
Permanent 12V DC output
This output is connected directly to the input 12V XT60 socket. Can be used to provide power to a mini PC or
any other device powered with 12V.
Adjustable DC output
Internal switching converter provides regulated voltage in a 3-10V range that can be used to power any
peripheral devices (DSLR, USB hub, etc.) Voltage can be adjusted with a 2mm flat screwdriver using a small
potentiometer.
Sensors
AstroLink 4 Pi can be equipped with a DS1820 temperature sensor to monitor ambient temperature. The
temperature reading is available in the dedicated INDI driver panel and can be used to perform temperature
compensation of the focuser position.
