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Digital Readout Windlass
Zero Shift Focuser
Low Temperature Thermostat

I enjoy designing and building electronic projects.  As time permits, I am going to document projects here for the benefit of all.  I use microprocessors from MicroChip.  Typically the 16F87x series.  These come in several versions from 28 pin skinny dip to 44 pin PLCC, with speeds up to 20 MHz which provides an instruction execution time of 200 nsec.

900GD-DRO - Windlass Digital Readout - this provides a digital readout in the cockpit of the length of chain is currently out to the holding anchor.  It features a button to set the length to zero, a hold button that allows the windlass to be used with another anchor, a pair of buttons to control the brightness of the LED display.

ZSF - Zero Shift Focuser - on commercial schmidt-cassegrain telescopes (such as made by Meade and Celestron), focusing is done by moving the primary mirror forward or backwards.  This motion introduces an unwanted motion in the form of the primary mirror "rocking", which in turn causes the final image to move sideways.  In an eyepiece with a large field of view, this is just an annoyance.  For a CCD camera which has a small field of view, it can cause the image to move off the CCD.  One answer to this problem is to use the normal focuser for coarse focus and an auxiliary focuser between the telescope and CCD camera that allows fine focus and has no shift. 

Low Temperature Thermostat for Heat Pump - In order to keep from freezing in the winter, a heat source is required.  Typically a small 1000W/1500W electric heater is placed in the main cabin.  Not wanting to use a portable electric heater, I wanted to use the primary heat pump on board.  However, the thermostat that comes with the unit will only allow you to go as low as 60F.  Regulations at the marina require that the interior of the boat be no more than 40F.  This project allows me to use the heat pump and still be within marina regulations. It uses a Dallas Semiconductor DS1620, set up as a stand alone thermostat.

Please Note:  All projects are the property of David V. Fansler, who does give permission for them to be duplicated for personal use only.  Any commercial use is prohibited without a contract.


Please address general comments to web@dv-fansler.com

This page was last modified: 01/22/14
This Document is Copyright 1998-2014 by David V. Fansler  All rights reserved.
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