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MSP430 Controller Board

A project log for Astrophotography Camera Mount

A 3D-printed 10000 : 1 gear reducer and control hardware used for astrophotography

ChrisChris 02/05/2019 at 01:160 Comments

The controller for this project is by far the most complicated thing I've personally designed. Schematic and board were built using KiCad 5 and fabbed at OSH Park.

There are a few major blocks:

The board is a four layer stackup. Components and routing on top, 3.3V power plane, ground plane, and more routing on the bottom. The entire thing is hand-soldered, which isn't much of an accomplishment except for the 24QFN package of the MCU. Flux and drag soldering win the day!

The firmware is pretty simple. On powerup the MCU initializes the necessary peripherals and draws an opening menu to the LCD. The user can select speed  (sidereal tracking or lunar tracking), timer (10 - 60 seconds on the shutter), and then start the driver. While the driver is engaged the MCU PWMs a signal to the A3967 at the rate selected by the user until the user says "Stop."

This is still a work in progress. The latest fabbed boards had a couple of traces swapped so that the MCU was PWMing the driver's DIR pin instead of STEP. Fortunately the traces were readily accessible!

The shutter control feature is also totally untested. To date I've been mostly focused (lol) on getting the basic drive mechanics going.

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