AlpacaPi - Drivers

AlpacaPi Drivers

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AlpacaPi is the name I have given to my suite of Alpaca drivers and clients.

The drivers are probably the most important piece to the puzzle. Once the driver is running for a particular device, then any program that speaks Alpaca can utilize that devices. This also includes a web browser. However you can not send action commands to the driver from a web browser. You can read all of the status.

The AlpacaPi drivers run on Linux and were designed with the Raspberry-Pi in mind. They will run on most any flavor of linux.

AlpacaPi drivers currently support the following devices.

Cameras
- ATIK cameras
- FLIR grasshopper series cameras
- QHY cameras
- QSI cameras
- SONY A7 R IV DLSR camera
- TOUPTECH cameras
- ZWO cameras
Domes
- Raspberry Pi w/Motor control board for dome
- Raspberry Pi w/Motor control board for Roll Off Roof
Filter Wheels
- Atik filter-wheel
- QHY filter-wheel
- ZWO filter-wheel
Focusers
- Moonlite NiteCrawler
- Moonlite High Speed Stepper
Observing Conditions
- Raspberry Pi with sensors
Rotator
- Moonlite NiteCrawler
Switches
- Raspberry Pi with a 8 Relay board
- Raspberry Pi with a 4 Relay board
- Raspberry Pi with a WaveShare 3 Relay board
Telescope (Mounts)
- Talks LX200 via TCP/IP to tsc mount controller
- Rigel - Custom driver for Jim H.
- Raspberry Pi with Servo controller
- Skywatch

Client and server operation

To utilize any of the drivers, first you have to build the driver and run it. Then you run the appropriate client program to access that driver. In my environment, there are normally on separate machines, the driver running on a Raspberry-Pi and the client program running on my Linux desktop computer. They can also be on the SAME machine.

For example, if you want to utilize the 4 port switch (described below), follows these steps:

On the driver machine
1. make piswitch4
2. ./piswitch4
On the client machine (can be the same as the driver machine)
1. make switch or make switchcv4
2. ./switch

You should then get a screen like the screen samble below:

Dome	Focuser	Switch

Dome driver

The AlpacaPi dome driver supports the following configurations:

Dome with rotation and single shutter
- This option uses DC motor controllers
Roll Off Roof with roof acting as the shutter
- Version using relays for driving motors
- Version using DC motor controllers

A watchdog timer is also supported to close the dome if communications is lost.

The watchdog timeout occurs if no commands have been received for the specified time. (default is 5 minutes). If SkyTravel is being used, it queries the dome driver every few seconds for status thus resetting the timeout. The Dome watchdog timer controls the dome shutter. If the timeout occurs, the shutter will close.
The Dome movement timeout occurs if no MOVE command is received in the specified time (default is 2 hours). The Dome movement timer controls the dome position. If the timeout occurs, the dome will be sent back to the PARK position

Remote Shutter

The AlpacaPi dome driver supports the option of a separate drive that controls the door. This allows one device driver to be used for the dome since most client applications can only deal with one. While in reality there are 2 drivers. The primary DOME driver talks to the second driver (SHUTTER).

The SHUTTER devices is a non-standard Alpaca device. It will not be recognized by other Alpaca clients. It responds to the same door/shutter commands as the DOME device.

The AlpacaPi dome driver uses DC motors and a PWM controlled DC power board that handles reversing and power output. It also uses a terminal I/O board for connection to the DC controller and for sensor inputs. The sensor inputs are for door open and door close. Additional inputs can be used for positions in between.

The Raspberry Pi only has one PWM (Pulse Width Modulation) for speed control. I use one R-Pi for dome rotation and a second R-Pi to control the door. This allows the door controller to be mounted on dome and use wireless to talk to the dome rotation controller that is mounted on the wall.

Description	Power board	build / run commands	Notes
DC motor control	Click here for amazon description Click here for amazon description	make dome ./domedriver

Raspberry-Pi Dome Driver
Hardware configuration
Using BCM Pin numbering
Clockwise button pin	23	Input
Counter Clockwise button pin	24	Input
Stop button pin	25	Input
Direction Control pin	27	Output
Power PWM pin	18	Output
Home Sensor pin	5	Input
Park Sensor pin	6	Input

NOTE: These pin numbers can be changed, this is the default list.

Switch driver

The switch driver on the Raspberry Pi requires the wiringpi library to be installed. At present, the wiringpi library only works on the 32-bit versions of Raspberry Pi Linux.

Description	Relay board	build / run commands	Notes
8 Relay DIN mount	Click here for amazon description	make piswitch8 ./piswitch8
4 Relay	Click here for amazon description	make piswitch4 ./piswitch4
WaveShare 3 Relay	Click here for amazon description WaveShare product page WaveShare manual	make piswitch3 ./piswitch3	This board has inverted logic to the relays. A logic "0" turns the relay ON. This may cause issues on start up.
keyestudio 4 Relay	Keyestudio 4 relay	make piswitch4ks ./piswitch4