Designing a simple case, advice on doing it? - Page 1
Forum section: electronics / projects

author: TriodeTiger
author_rank: Regular Contributor
timestamp: March 09, 2012, 11:02:32 pm
content: I have always wanted a variable bench power supply, without the $100 for a predesigned one with fancy case and constant current, only wish for current limit and lower power (<1A). Anywho, so I am planning on how to design the case and more importantly knowing what tools/tips I need in doing so for any similar project.My case is going to be a suitable ABS plastic from Ebay, there are a lot of flavours out there however I would certainly be open to anything else (rugged enough for a power supply) if it is less costly to build it.I guess I need advice for making the following:Square slot to fit a seven segment LED displayVarious holes for LED, DC jackA female plug interface for +/0/- railsA drill for LEDs/jacks (hopefully inexpensive, and kinda fun) and square nibbler looks like it would work, what is your opinion?:Jack wise, I came to like the look of Dave's uCurrent banana jack setup, Jameco (only place that ships with USPS for no brokerage fees to Canada AFAIK) sells them for $20, ick, however Ebay seems to have a lot for cheaper, i.e.http://www.ebay.ca/itm/8-pcs-Binding-Post-Speaker-Cable-4mm-Banana-Jack-L33mm-/180574089184?pt=LH_DefaultDomain_0&hash=bin2a0b0defe0I do not think I care for banana plugs, just wrapping a wire around it and tightening seems to be as simple as I want it.Can any of you see any flaws, provide tips/tools or give advice to me about DIY case making, or have I already answered all of my questions with a little research?Alexander.

author: IanB
author_rank: Super Contributor
timestamp: March 09, 2012, 11:11:24 pm
content: What about ventilation/heat sinking?Even a low power regulator will need some cooling for the heat sink otherwise the heat will just build up inside the case. The two options seem to be (1) attach the heat sink to an external metal feature of the case or (2) include some ventilation holes in the case so air can circulate.

author: TriodeTiger
author_rank: Regular Contributor
timestamp: March 09, 2012, 11:19:47 pm
content: Quote from: IanB on March 09, 2012, 11:11:24 pmAbsolutely you are right, I was thinking of making some parallel lines (maybe with heated knife scoring ) for air flow, heat sink kits are very cheap, and a fan in the right location if I measure it too hot should do nicely. Hopefully that'll be the easiest part of the case modification.I was considering a uC to drive a lot of this, so maybe a PWM fan will be a fun task, may leave out until I upgrade if need be to an LM350K (over this project's LM317.)edit: The square punch was originally a tool for metalwork, and drills obviously work with thin metal. May try out an Alu. case later on.

author: kaptain_zero
author_rank: Regular Contributor
timestamp: March 10, 2012, 12:29:05 am
content: For those binding posts, I think you can do better on Ebay. I've ordered from this site before and have been happy with the product and shipping:http://goo.gl/nkRaVI also happen to like these dual binding posts in one... neat and tidy.RegardsChristian

author: TriodeTiger
author_rank: Regular Contributor
timestamp: March 10, 2012, 12:42:14 am
content: Quote from: kaptain_zero on March 10, 2012, 12:29:05 amAh, if I am to add +/0/- rails a double + single jack would look shabby if misaligned, will save those double ones for everything that does not require dual polarity - like a secondary output for something else.I am quite excited to purchase a drill and mount those on, since the plastic will cover any shoddy holes or rough plastic and be nice and snug. I love panel mounting stuff. Now to purchase from 4+ people at the same time and hope nothing gets lost in the mail..If there is a better tool than a square nibbler punch thing for making rectangles do tell, anyone.

author: kaptain_zero
author_rank: Regular Contributor
timestamp: March 10, 2012, 12:53:34 am
content: For a few square holes, a nibbler is the way to go. To make it perfect, punch it out undersized and use a file with a safe edge to finish.If you are not well practiced with a file, you might as well just use the nibbler.Apace also has the single bind posts you show in your first post, not sure what their quality is like on those, but they have other ones too if I recall correctly.RegardsChristian

author: TriodeTiger
author_rank: Regular Contributor
timestamp: March 10, 2012, 05:52:20 am
content: Very nice, I can file it clean and add padding and front plastic to make it look nice. Down to designing and ebaying, will make a followup post or thread if I do awesome on it.

author: Psi
author_rank: Super Contributor
timestamp: March 10, 2012, 06:44:24 am
content: Quote from: Alexander on March 10, 2012, 12:42:14 amNa, nibblers are the best i've found.Or, you can get the front panel made out of printed circuit board.That way all the holes get done for you and in exactly the right location. You can also put silkscreen text/lines on the front for labeling things.I'll let Mike explain it

author: steve_w
author_rank: Regular Contributor
timestamp: March 13, 2012, 01:40:35 am
content: Excellent video on the PCB, where did that come from, are there more?regardsSW