Ammo can power supply. (Part 1)

Read part 1 here , part 2 here , part 3 here , part 4 here or part 5 here.

So. I got need for variable power supply.

I searched through options from various stores, but +150€ for somewhat good about 30V 2A psu seemed expensive, so i decided to make my own. I found video from youtube about variable regulator LM317. so this was the way i wanted to go. Linear regulators are not best. They are not efficient and have minimum voltage of 1.25V but it's easy to make.

Some of the parts i got from local electronics store Partco, some i bought from Ebay and rest from scrap bin. Power supply i built into "beautiful" wooden box. But the looks were not what i was going for. I wanted something that works and gives me voltage i need without need for me to go and find suitable transformer from some box.

Whole thing is based on couple pieces. Transformer, 12V regulator for fan, 5V regulator for voltage display and power led. Massive (100µF!) cap for incoming voltage, relay and batteries for current meter, big AMD heatsink for LM388 regulator and thermometer connected to the heatsink.

PSU works and looks ok.

 

(old picture is old. oldest pic in the blog.)

Sadly 10Kohm potentiometer on the front panel, that you used to change voltage decided to break and throw voltage around in places. 1.5V -> 6V -> 1.7V and so on. At this point i decided it's time to build new better and nicer power supply and put old one to retirement.

I had for some time looked Tuxgraphics power supply and decided to order it.

Couple weeks passed and i got the parts. They laid on my table for some time till i got the components soldered on the PCB, programed the atmeaga and tested it works. After that it was "pending" for some time still before i started to make the case for it. I had already before decided i'll put it in the .30cal ammo can.

 

 Ammo can from Varusteleka.

First was to make sure that there is place for the biggest visible component. The LCD display. So i started with that.

Drilled 4 small holes into corners where the display will be.

 

Used dremel to remove the metal between the holes and filed it square.

 

LCD-display fits neatly to the hole.

I also decided i'll attach rubber feet to the bottom of the case to keep it in place when it's on the table.

Also drilled 3 holes where i will put on screws to mount the transformer.

 

Transformer is from HP printer. It outputs 32V @ 2500mA. It's just great size for the tuxgraphics power supply, on which the 30V 2A model was made for 32V input voltage.

This is first episode of the build log. Next we'll somehow get the 230V into the box.

-Jokke