Power box
Fitting the Electronics
Contents
As this is quite a large project, I've decided to split this project into several pages. Each page dealing with a different aspect of the project.
This is the part of the project where we start pulling the other parts of the electronics together. I wanted a little fuse board inside the project box, to help provide a little protection to the scope, heater and aux circuits. For this I etched a board and fitted 20mm fuse holders. I've made provision to hold 4 fuses, but I'm not sure if/when the fourth will be used. Also this provides a neat way of providing power to all the circuits, and it will cut down on the number of wires. You wouldn't believe it from the spaghetti in the pictures.
I didn't take any contruction photos for this project, as I wanted to crack on and get it finished. The method for construction was to cut all the holes in the box, then fit the circuit boards. The only thing holding the two graph circuits in place is the pressure on the LED's you need to be careful not to break the tracks holding the LED's in place. Once fitted, I then added the wires to connect all the switchs and boards together. I've used wire that is overrated for the amount of current that I'm going to use for each part of the project. On the right hand side of the box, you'll see the 8 pin DIN that is used to for the cable that connects to the scope's distribution box. It's important that this is wired corrected and tested before plugging into the scope.
The fuses that I used in this project are all the quick blow type, with ratings of 2amp for the scopes power line, 3.1amp for the aux circuit, and 6.3amp for the dew heater circuit. The Vellman board provides the upper limit for the dew heater circuit, as it has been rated as 6.5amp Max, 6.3 should mean that the board is sufficiently protected, whilst allowing maximum performance from the heaters.
It would have been nice for the switchs to be illuminated when they are turned on, however, the type of which that I used needs a much high voltage in order for that feature to work. If I had to re-make this project, I'd use different switches that will illuminate on the 12v supply. Maybe I'll do this modification one day. It'll mean a new box lid though.
©Copyright 2005 Colin Dawson
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