Makers should make things that work

In the March/April issue of CQ, Rich, W2VU wrote the “Makers” column for the regular editor. He writes about a one-tube transmitter that he built. It sounds like an interesting project, but then he says:

I haven’t actually gotten to testing it out yet. I still need to get a crystal and wire-up the connectors for power, antenna, and a key….Frankly, I don’t really care if it works (that would be a bonus, of course), but for me, the real fun was in the building (I’m sorry, making), from staining the wood to winding the coils and putting it altogether. As far as I’m concerned, it’s a piece of electronic art that I’m proud to have in my shack.

While I agree with W2VU that it does look very cool, I would really want to do what I can to make it work. While it might be fun to look at, the real pleasure comes from building something that you can put on the air and make contacts with. Makers should make things that work.

How do you know that fuse is protecting your circuit?

How do you know that this fuse will protect your rig?

How do you know that this fuse will protect your rig?

I blog for a leading manufacturer of circuit protection devices, so I keep my eye out for articles on fuses, ESD diodes and the like. Recently, I came across the article, “Fuse selection factors critical to circuit design.” Among the factors discussed is:

11. Application testing/verification prior to production.
Request samples for testing in the actual circuit to verify the selection. Before evaluating the samples, make sure the fuse is properly mounted with good electrical connections, using adequately sized wires or traces. The testing should include life tests under normal conditions and overload tests under fault conditions to ensure that the fuse will operate properly in the circuit.

Being a former test engineer, this got me to thinking about how one would actually do this. For example, how would you test that a fuse will actually protect a circuit board? Would you inject faults, i.e. deliberately short-circuit nodes? If so, which ones?

What measurements would you make to ensure that the fuse was working as you hope? Would you measure the time elapsed between the time you injected the fault until the time the fused actually blew? How about measuring the current profile over that period of time? That might be important and/or tell you something about the failure.

What kind of fault analysis should you perform after the fuse has blown? I suppose at the very least you’d want to replace the fuse and ensure that the circuit is functioning again. I would say that you should also run a full performance test to ensure that the fault didn’t adversely affect the board’s performance. Also, I’d think that you’d want to visually inspect the board to ensure that the fault current didn’t damage the board or traces at all.

I’m curious if any of you have had any experience with this kind of development testing. If so, please e-mail me or comment here.

From the trade magazines: Beagle Bone add-ons, DIY 555, using digital scopes

Giant 555Build Your Own Giant 555. This is definitely not practical, but it is fun. It’s educational, too!

BeagleBone: 9 Add-Ons That Power It Past Raspberry Pi. I have a BeagleBone, and while I haven’t played around with it a lot yet, I am liking it. I think it’s a better choice for amateur radio apps than the Raspberry Pi.

How to Use a Digital Oscilloscope. Now that scopes are so cheap, more and more hams have them. They do work differently than analog scopes, and this course will help you use yours better, if you have one.

From my Twitter Feed: Hamvention record, SW radio

N2NKW's avatarN2NKW
@hamvention I sure will if I can get a working radio. Did you know #hamvention in 1960 pressed a 45rpm record? youtube.com/watch?v=lOqe0o…

 

SWLingDotCom's avatarSWLing @SWLingDotCom
Another solution for whole-house shortwave goo.gl/fb/HKiw9#shortwave#swl#dx

 

hackaday's avatarhackaday @hackaday
New post: [Balint]‘s GNU Radio Tutorials bit.ly/1i5LYHv

 

MW0IAN's avatarIan @MW0IAN
XMEGA-A3BU Xplained | AD9850 DDS controller firmware   kd1jv.qrpradio.com/XMEGA/XMEGA.htm

Coiling Cables

A couple of years ago at Field Day, Bruce, KT8TD, tried to show me how to coil cables properly. using the “over-under” technique. Using this technique helps prevent cables from getting all tangled when you uncoil them. I really was too tired at the time to pay much attention, and I never really learned the trick.

Yesterday, though, someone on Twitter posted a link to a Boing Boing post that describes the technique and links to a YouTube video (below) that shows you how to do it. I practiced with some tangled cables I had laying around the shack, and now think that I can coil with the best of them. Try it. It really works.

From my Twitter feed: amateur radio course, SwiftKey, BeagleBone

Radio_2_Radio's avatarRadio Guy @Radio_2_Radio
Amateur Radio: Ken Green's Amateur Radio Course – Clovelly Donkeys ow.ly/2FczP1

f6fvy's avatarLaurent Haas – F6FVY @f6fvy
Typing revolution : SwiftKey for physical keyboards bit.ly/1fkNPq6 #contesting #ohWait

DIYEngineering's avatarDIY Engineering @DIYEngineering
Boost Your BeagleBone Black with Breakout Board – Making a PCB is easier than you might expect. Read more on MAKE ow.ly/2FireZ

From my inbox: radio demos, free EM simulation, radio builder’s BBS

Here are some items of note from my inbox:

  • My partner in crime down at WA2HOM, Ovide, K8EV, is working with Professor Ray, who does science shows for kids down at the Ann Arbor Hands-On Museum, to develop a show about radio. In researching this, Ovide happened across the Happy Scientist’s experiment on AM and FM radio waves. There are a bunch of other interesting experiments on the site, but you have to subscribe to the site, in other words pay, to view them.
  • openEMS is a free and open electromagnetic field solver using the FDTD method. Matlab or Octave are used as an easy and flexible scripting interface. I haven’t yet tried this out, but it sounds like a neat tool to play around with.
  • TheRadioBoard is a forum for the homemade radio builder. There are forums for crystal radio builders, tube radio builders, and solid state radio builders, as well as a swap forum and antenna forum.

From my Twitter feed: bipolar transistors, homebrew Buddipole, Dayton survival

Planet Analog ?@PlanetAnalog 11m
Bipolar Transistor Circuit Design & Analysis, Part 1 – There are many applications for one or two transistors. Th… http://ow.ly/2EzTJR 

 

n1pce's avatarJohn Ryan @n1pce
Homebrew Buddipole with Modifications: youtu.be/Z6ATX2Z9ews via @YouTube

You don’t have to pay a lot for a Buddipole. By making one yourself, you can not only save money, but learn something in the process.

ke9v's avatarJeff Davis @ke9v
Dayton Survival Guide ke9v.net/articles/dayto…

The Dayton Hamvention, still the largest gathering of amateur radio enthusiasts in the world, takes place May 16-18, 2014. While I disagree with Jeff’s statement, “There’s simply no way to facilitate that size of a crowd for three days in an ultra modern facility,” the rest is pretty much spot on.

From my Twitter feeds: Smith chart, inkjet PCBs, SW books

imabug's avatarimabug @imabug
Smith chart antenna-theory.com/tutorial/smith…

 

make's avatarMAKE @make
Inkjet-printed circuits being shown at #sxsw. More to come. pic.twitter.com/ohLNzedwSk

 

hamrad88's avatarTom Stiles @hamrad88
TRRS #0252 – Books for Shortwave Listeners: youtu.be/rBFLkHP8RiU?a via @YouTube

From my Twitter feed: clear-top boxes, SDR, HSMM

LA3ZA's avatarSverre Holm, LA3ZA @LA3ZA
Show off your project in a clear top tin la3za.blogspot.com/2014/02/show-o…

roteno's avatarVictor Laynez @roteno
Fun little radio housing. pic.twitter.com/QtmCw2smuW

DIYEngineering's avatarDIY Engineering @DIYEngineering
Using SDR to Read Your Smart Meter – [BeMasher] was dissatisfied with the cost of other solutions to read his smar… ow.ly/2EcLiT

kc5fm's avatarkc5fm @kc5fm
An Old Buzzard’s Guide to Getting Started with HSMM-Mesh bit.ly/1eL1cQg #ARRL #hamradio