Star tracker

I had some spare acrylic from another project, so I decided to get this project underway. The basic idea is very similar to Alex Kuzmuk's design. https://kukuruku.co/post/diy-an-astro-tracker-in-two-nights/ I desired a simple and reliable star tracker, that was also small enough to carry, particularly for hiking or travelling. The use of the Arduino provides a lot of flexibility in gear and thread choice. Mine uses an M6 thread to drive the barn door. You may need to adapt it to your tripod/camera mount. There's a 6.5mm (1/4) hole for the camera mount. I used a 3d printed base for a ball joint from an old monopod, bolted in with a 6mm bolt. The tripod mount is designed to fit my Vanguard tripod with foot dimensions of 10mm high, top 32.3mm square, base 42mm square. There's a couple of potential improvements that could be made. The hinge could be redesigned to incorporate bearings (see update 19/06/17). The gear system could benefit from bearings as well. In a 'perfect' system, the main gear would rotate around a bearing, and the guide rod would be constrained by the gear. In this model (and most other barn door star trackers) the threaded rod constrains the main gear, and is itself constrained by the hole in the acrylic. As the hole in the perspex has to have some leeway for the threaded rod, this could result in vibration or oscillation as the rod and gear move around the hole. This design includes a picatinny rail for mounting a sighting scope. Electronics consists of an Arduino Nano (just the board - no riser pins), an illuminated switch, and a 5V BYJ48 stepper motor. Speed control is defined in the code, so just flick the switch to start tracking. https://youtu.be/23A9o62kssQ I'm not going to draw a sketch for the electronics. I'll just list the wiring below. There's not much clearance in the case for wiring, so be neat. :D Pin 12 -> switch -> ground Pin 3 -> stepper IN1 Pin 4 -> stepper IN2 pin 5 -> stepper IN3 pin 6 -> stepper IN4 5V -> stepper positive Ground