It's been quite a while since I last published a post, which was partly due to a 3 week 'holiday' back to the UK which left me with a lack of time; partly due to a lack of progress in any of my electronics ventures (due to a lack of time); and partly because I haven't been at all convinced by the reliability of my blog audience stats, and wanted to keep away from blogger for a while to check if it was simply my own activity on any one of 3 different devices, using 2 different browsers, that was giving me 'hits' despite me trying to block it from recording my own activity. Well - after a couple of months away from blogger - I can confirm, depressing though it is... I have absolutely no recent activity at all, so it looks like I am totally wasting my time, and nobody reads this at all. So if nobody reads this, why am I bothering to tell you if you aren't going to read it anyway? Ah well - it is an outlet for my frustration - so I may keep on writing just for the hell of it.
So - on with the post... I have finally completed building my 'Regulator Box' for the bench power supply. The idea was to provide a buffer between unregulated supplies (such as various mains powered wall plug supplies rescued from defunct IT equipment, all of which appear to produce around 50% over-voltage when under little or no load) and the Arduino and breadboard power supplies.
The Arduino can allegedly be fed by up to 20v (though I'm not sure I want to put that to the test), but the breadboard supply will only take a maximum of 12v - as I found to my cost. I plugged one of the aforementioned wall plug supplies into it, that was rated at 12v @ 1000mA, but I later discovered that it was massively NOT putting out 12v as advertised, but actually providing over 17v at the few milliAmps that the PSU on its own was drawing. This very quickly fried the 5v regulator and rendered the PSU useless - but more on that in my next post.
So, what I am planning is for all of my power supplies that plug into the mains and produce vastly different voltages to what is claimed on the specs, as well as the 12v batteries that actually put out anything from 11 to 13v, and the solar panel charge controller (if I ever get solar on the roof) which will be controlling an 18v input under ideal conditions... all of these will plug into my new regulator box. There is an LED display showing the input voltage present (0-30v), and that is fed into the buck converter (which can handle up to 40v). The buck converter is adjusted to provide a regulated 9v output, which is shown by a second LED display, and then made available to my projects via two 2.1mm plugs which can then feed the Arduino and breadboard PSU safely.
I managed to shoe-horn it all into a little project box which is frosted transparent plastic, so with the LED displays pushed up against the case from the inside, they can be read from the outside without the need to cut any holes for them. I drilled a small hole above the adjuster screw on the buck converter, just in case I want to fine tune the output voltage (which does seem to vary slightly based on the input voltage overhead). In terms of construction, I used a hot glue gun to stick the LED displays onto a strip of clear plastic cut from an old tape cartridge box, pushed them right into the bottom of the project box (face down), and then used the hot glue gun to tack the strip in place on the sides. I then did a similar thing with the buck convertor, screwed on the lid, then turned the whole thing upside down so that all the components that were facing downwards, are now at the 'top' of the box. It's not the prettiest thing, but it is functional, and keeps everything contained - I'm happy with it.
No comments:
Post a Comment