eFinder Build Instructions

Building your own eFinder is relatively easy. Just a little soldering is required and a box drilled and cut to take the display.

You will need a camera and lens. Currently the code only works with ZWO ASI cmos cameras. I recommend the ASI120MM-S.    A 50mm f1.8 cctv lens is ideal.

For a small fee a copy of the code is available. This has been primarily developed to work with telescopes controlled by a Nexus DSC. Each installation will be different though and I can provide some help in modifying the code to suit. Please contact me if you want the code. This isn’t a commercial product, so please be prepared for some ‘work in progress’ and bugs.

Parts List - control & display box

1x Box. I suggest one of the commercial raspberry Pi cases that has an extended height, which will accomodate the LCD display. 

1x Raspberry Pi 4b 4GB

1x 16GB microSD card

1x display module. Adafruit RGB Negative 16x2 LCD+Keypad Kit for Raspberry Pi

5x 10mm high buttons (to replace the short ones on the LCD module.

1x 10k ohm potentiometer (optional, to adjust display brightness)

1x USB to TTL cable (using the PL2303 or FTDI chipsets)

assorted small screws and nuts.


Thats it! (All these parts are available from the Pi Hut)

The LCD display does get a bit sluggish at cold temperatures, but otherwise it is nice and readable and has 5 built in buttons. Other types could be used, but be prepared to modify the code!

Control Box Schematic

Screenshot 2022-04-30 at 12.44.10


Screenshot 2022-04-30 at 12.45.26

Wiring List

This table lists the wiring required to the Pi. The LCD module does come with a ‘header’ that will plug directly into the Pi, but that restricts subsequent mounting into a box, and covers the pins needed for the Nexus USB connection (but these could be soldered on)

When assembling the LCD module, replace the 220 Ohm fixed resistor labelled “red” with the 10k ohm variable resistor. Also, replace the supplied push buttons with the 10mm high ones.

On first powering up, the LCD will probably look blank. Adjust the contrast pot on the module to get a clear display.

Click here for a gallery of photos of the eFinder build

© AstroKeith 2022