Custom telescope mount using harmonic drives and ESP32

Summary

TL;DR → The Spark Early Orion Nebula capture A few years back, I developed an interest in astrophotography thanks to YouTubers like Nebula Photos. Armed with an OM System OM-5 and a 15-140mm Olympus lens, I managed some decent shots of the Orion Nebula from a tripod by taking 300 pictures with a 2-second exposure time and stacking them in Siril. Knowing I could achieve better results with tracking, I bought a Move Shoot Move tracker for around €200. It delivered longer exposures, but finding targets and achieving proper polar alignment remained challenging. I spent countless hours researching proper telescope mounts with GOTO and tracking capabilities, coming close to pulling the trigger on units ranging from €1,200 to €4,000. For a hobby I was still exploring, that investment always felt like a leap too far. The PCB Awakening Late 2024 I randomly came across this YouTube video about custom PCB design in my feed, and I was hooked immediately. With a decent collection of microcontroller boards, the idea of ditching messy breadboards for clean, custom, affordable PCBs was revelatory. My first project replaced my home thermostat with an ESP32-based design with e-paper display, interlocking finger patterns for the original carbon rubber dome switches and space for a Bosch BME680 sensor breakout. After completing that project, I revisited the telescope mount idea - this time armed with newfound PCB design skills. The question emerged: "How hard can it be?" Down the Research Rabbit Hole The plan crystallized around harmonic drives (strain wave gears) - the favorite of modern telescope mounts for their excellent performance in compact packages. The concept seemed straightforward: motor, microcontroller, optional gearing, and a strain wave gear, all housed in a sturdy enclosure. I divided my time between scouring AliExpress for components and studying existing DIY builds. AliExpress proved to have the worst search functionality in e-commerce history. Google's site:aliexpres...