ScopeDog eFinder

ScopeDog eFinder

Mailing list

For more help, you can subscribe to the eFinder mailing list at groups.io.

Source code

The source code can be downloaded from GitHub.

Needed parts

Purchase of the hardware

In the following list, you can see which hardware is needed to construct a working eFinder.

The Nexus DSC Pro cannot connect directly over WiFi to more than one machine (e.g. the eFinder and a tablet running SkySafari). To solve this, you can use an external router. The D-Link router is not needed if you use the Nexus DSC, as the problem does not occur on the Nexus DSC.

The Raspberry Pi has a poor WiFi connection when it is in a case. To improve the connection, you can add an external WiFi adapter. The TP-Link adapter is a good option. Instructions on how to set up the adapter are provided later in this document.

Since I live in Belgium, this section is focused on European suppliers. I purchased the ASI camera at Teleskop Service in Germany, and the rest of the components from suppliers in the Netherlands (Raspberrystore) or Amazon.

Ordered	Product	Company	Amount	Arrival
03/08/2022	Software	Keith Venables	€ 26.98	03/08/2022
03/08/2022	ASI120MM-S	Teleskop Service	€ 248.51	11/08/2022
03/08/2022	Raspberry Pi 4 model B - 4GB	Raspberrystore.nl	€ 74.95	10/08/2022
03/08/2022	Raspberry Pi Pico	Raspberrystore.nl	€ 3.99	10/08/2022
03/08/2022	2 x 1x40 header	Raspberrystore.nl	€ 2.00	10/08/2022
03/08/2022	Shipping costs Astroberrystore.nl	Raspberrystore.nl	€ 12.74	10/08/2022
03/08/2022	2.23 OLED Display Module for Raspberry Pi Pico	Amazon (.nl)	€ 20.99	09/08/2022
03/08/2022	Geekworm Raspberry Pi 4 Aluminum Case	Amazon (.nl)	€ 14.89	08/08/2022
03/08/2022	Sandisk Ultra 32 GB microSDHC	Amazon (.nl)	€ 8.01	08/08/2022
03/08/2022	100 x 60 x 25 mm DIY box	Amazon (.nl)	€ 10.62	08/08/2022
03/08/2022	Lon0167 Momentary Circuit Control Tactile Tact Push Button Switch	Amazon (.nl)	€ 11.31	16/08/2022
03/08/2022	50 mm F1.8 CCTV-lens for C-mount	Amazon (.nl)	€ 48.38	16/08/2022
10/10/2022	TP-Link 300 Mbps Wifi USB-adapter (TL-WN823N)	Amazon (.nl)	€ 9.95	11/10/2022
12/06/2023	D-Link DWR-932	Amazon (.com.be)	€ 54.83	14/06/2023
Total			€ 548.15

eFinder hardware configurations

The eFinder can be added to your telescope system in a variety of ways, depending on your specific needs and preferences.

Nexus DSC Pro, using SkySafari

A travel router is required when using SkySafari on a tablet with the Nexus DSC Pro. This is the needed hardware configuration:

The ServoCAT is connected directly to the eFinder using USB.
The ServoCAT is also connected to the Nexus DSC Pro using a serial cable.
The ASI camera and the eFinder hand box are connected directly to the eFinder using USB.
The Nexus DSC Pro is connected to the eFinder using USB.

Please use the following steps to install the eFinder

Install the Raspberry Pi 4
Create a RAM disk to store the index files
If using an external Wifi adapter, install the needed firmware
Install the latest firmware to the hand box
Connect the Nexus DSC Pro to the eFinder using USB
Update the Nexus DSC Pro to the latest firmware
Set up the Nexus DSC Pro

Using a Nexus DSC Pro, ServoCAT and SkySafari

Nexus DSC Pro, without using SkySafari

If you want to connect your tablet to the eFinder (for the GUI) then for the Nexus DSC Pro, you need a travel router. For the non Pro, the Nexus can act as a router.

Using a Nexus DSC Pro, ServoCAT and no SkySafari

Nexus DSC, using SkySafari

When using a Nexus DSC, a travel router is not required when using SkySafari on a tablet.

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Nexus DSC, without using SkySafari

When using a Nexus DSC, a travel router is not required when using SkySafari on a tablet.

Using a Nexus DSC, ServoCAT and SkySafari

Nexus DSC Pro

Update of the Nexus DSC Pro firmware

Remove the micro SD card from the Nexus DSC Pro.
Insert the micro SD card into a card reader of your computer.
Make sure that at least version 1.1.20 of the firmware is installed on your Nexus DSC Pro. If this is not the case, download the latest version of the firmware from the Nexus DSC pro webpage and copy the firmware image (nxpro.fw) to the micro SD card.
Make sure you properly eject the micro SD card from your computer.
Insert the micro SD card back into the slot of the Nexus DSC Pro.
Press and hold the OK button and turn the Nexus DSC Pro.
A screen is shown asking if it is OK to update the firmware. Press OK and wait till the update is completed.
In the info menu, the correct version of the firmware should be shown (1.1.20). The needed firmware version for the Nexus DSC is 1.4.14.

Network settings on the Nexus DSC Pro

Make sure the following settings are set on the Network page:

WiFi Mode: Access Point
DHCP: Disabled
SSID: Name the network
Password: Select a password or leave blank
Channel: 6 (The channel needs to be 6 to be able to connect the eFinder, a VNC client, and SkySafari on a tablet)
Protocol: LX200 (ServoCAT will not connect with the eFinder)

Specific settings on the Nexus DSC Pro

Change the Serial connection to ServoCAT, 19200, 8, 1, None
Change the USB connection from ServoCat to LX200, 9600, 8, 1, None
Change Wifi to connect to Travel Router
- Infrastructure, set SSID, Password, DHCP Disabled
- Channel: 6
- IP Address: 192.168.0.19
- Mask: 255.255.255.0
- Gateway: 192.168.0.1
- Protocol: LX200
- TCP port: 4060
- Use EPOCH: JNow

Connecting the Nexus DSC Pro to the eFinder using USB

This is only needed when using a Nexus DSC Pro and SkySafari on a tablet!

As the Nexus DSC Pro is a host, a ttl to USB adapter is needed (from amazon.co.uk or amazon.com.be). This cable should be connected directly to the GPIO pins of the Raspberry PI, as described in the following table:

Raspberry Pi GPIO Pin
GND	USB to TTL lead, black
14	USB to TTL lead, green
15	USB to TTL lead, white
Not used	USB to TTL lead, red

The USB converter is powered via the USB from the Nexus. Do not have the red wire connected.

The pinout is as in the following picture:

Raspberry Pi Pinout

Enable ’serial’ on the Pi raspi-config set up:

sudo raspi-config

Select Interface Options, Serial Port, No Login Shell, Enable Serial Port hardware

The Nexus USB communication should be set to LX200, 9600,8,1,N

A useful test is to use the Nexus DSC in test mode monitoring the USB port, when switching on the eFinder. You should see the traffic as the eFinder asks for geo data etc. If not switch the green and white wires on the UART to USB cable.

Software

Raspberry Pi 4

Install OS and needed dependencies

Download the Raspberry Pi Imager
Select the standard 32bit Raspberry Pi OS.
In the settings, enter efinder as username, efinder as password, and efinder.local as hostname.
Start the installation of the OS.
Checkout the eFinder software from GitHub

cd ~
git clone https://github.com/WimDeMeester/eFinder.git eFinder

Install all dependencies

cd eFinder
sudo ./pi-install.sh

Change the resolution for the vnc server, by starting

sudo raspi-config

Reboot

Install the ZWO ASI Linux SDK

Download the SDK from the Developer tab of the driver page.
Unpack the SDK:

wget "https://dl.zwoastro.com/software?app=AsiCameraDriverSdk&platform=macIntel&region=Overseas" -O ASI_linux_mac_SDK.tar.bz2
bunzip2 ASI_linux_mac_SDK.tar.bz2
tar xvf ASI_linux_mac_SDK.tar
cd ASI_linux_mac_SDK_V1.27/lib/
sudo mkdir /lib/zwoasi
sudo cp -r * /lib/zwoasi/
sudo install asi.rules /lib/udev/rules.d

Start eFinder

Activate a python virtual environment (do this every time):

poetry shell

Run the VNC Gui version of the app:

python src/eFinderVNCGUI.py

The headless version can be started using the command:

python src/eFinder.py

Run the VNC Gui version of the app without having a handpad, a camera or a nexus device. (The headless version has no command line options at the moment)

python src/eFinderVNCGUI.py -fh -fn -fc

An easier way to start the app is executing scripts/start.sh for the headless version and scripts/startVNCGUI.sh for the GUI version.

Start eFinder automatically after boot

Find the PATH

echo $PATH

Adapt crontab:

crontab -e

Add the PATH and the DISPLAY variable to the crontab

export PATH=<The returned path from the echo $PATH command>
DISPLAY=:0
@reboot sleep 20 && (/home/efinder/eFinder/scripts/start.sh > /home/efinder/logs.txt 2>&1)

It is not possible to start the VNC GUI version automatically from crontab.

@reboot sleep 20 && (cd /home/efinder/Solver ; /usr/bin/python /home/efinder/Solver/eFinderVNCGUI_wifi.py >> /home/efinder/logs.txt 2>&1)

Create a RAM disk on the Raspberry Pi

Edit /fstab to add the line:

tmpfs /var/tmp tmpfs nodev,nosuid,size=10M 0 0

Save & exit

Execute in terminal sudo mount -a

Install RTL8192EU driver for the TP-LINK TL-WN823N

Install the needed packages

sudo apt-get install git raspberrypi-kernel-headers build-essential dkms

Clone the driver from the GitHub repository

git clone https://github.com/Mange/rtl8192eu-linux-driver
cd rtl8192eu-linux-driver

Make sure the following lines are in the Makefile:

CONFIG_PLATFORM_I386_PC = n
CONFIG_PLATFORM_ARM_RPI = y

Add and install the driver to DKMS

sudo dkms add .
sudo dkms install rtl8192eu/1.0

Make sure the driver is loaded correctly

echo "blacklist rtl8xxxu" | sudo tee /etc/modprobe.d/rtl8xxxu.conf
echo -e "8192eu\n\nloop" | sudo tee /etc/modules

Fix possible plugging/replugging issue and sforce the driver to be active from boot:

echo -e "8192eu\n\nloop" | sudo tee /etc/modules
echo "options 8192eu rtw_power_mgnt=0 rtw_enusbss=0" | sudo tee /etc/modprobe.d/8192eu.conf;

Reboot the system

sudo reboot

Configure the new Wifi network
Disable the Wifi card from the Raspberry Pi by adding the following lines to /etc/modprobe.d/raspi-blacklist.conf

sudo bash -c 'echo "blacklist brcmfmac" >> /etc/modprobe.d/raspi-blacklist.conf'
sudo bash -c 'echo "blacklist brcmutil" >> /etc/modprobe.d/raspi-blacklist.conf'

Reboot the system

sudo reboot

The Raspberry Pi Pico handbox

The software for the Raspberry Pi Pico handbox is written in micropython. We first need to install micropython on the board.

Download Thonny from the website.
Connect the Raspberry Pi Pico to your computer, while pushing the reset button.
Start Thonny and select to install micropython (at the bottom right).
The Raspberry Pi Pico will automatically reboot and install micropython.
After the Raspberry Pi Pico was restarted, open main_eF1_2.py in Thonny and select Save As.... Select the Raspberry Pi Pico and save the file as main.py. The screen of the handbox should show ScopeDog - with eFinder - waiting for host.
Once this is loaded (as main.py) the usual Thonny stop won’t work. To stop the code (ie for an update) plug in handset with ‘OK’ button pressed.

Changelog

The changelog of the software can be found here.

Hardware

Adding the OLED display to the Raspberry Pi Pico

Solder the header to the Raspberry Pi Pico. Check if you are soldering the header to the correct side of the Raspberry Pi Pico (I soldered it the wrong side first).
Make sure to also solder a cable to GP16, GP17, GND, GP18, GP19, and GP21.
Push the OLED display on the soldered header.

Connect to the Nexus DSC wifi

Set up the Pi wifi to ‘know’ the Nexus DSC wifi DSC & password. That way on Pi boot it will always look for the Nexus wifi and connect as a priority.

How to work with the handpad

In the VNC GUI version

Simple press: Capture/solve & display RA, Dec & deltas.
Up: Nexus align or Local Sync
Down: Goto++

In the handpad version

Development environment

Poetry

Install poetry to manage the python dependencies.

Install the dependencies and the virtual environment (do this once):

poetry install