Category Archives: Homebrewing

Articles and other information related to Homebrewing, station building, kit building, and other custom Ham Radio projects.

Add 16 Digital IOs To Your Next Arduino Or Raspberry Pi Project

Below is my Arduino based CW iambic keyer.  I wanted to be able to change my WPM on the fly using a potentiometer.

Ham Radio Arduino Based Display

I had some LED 7 segment displays that would be perfect for this application.  The issue then becomes how do I not use up all of my IOs…   Below is the IC that I used.

Data SheetMicrochip Technology MCP23017-E/SP

This IC is much cheaper than a multiplexing IC for 8 digits.

Now I have plenty of IOs left over for buttons to Call CQ,  give my callsign, and QTH etc.

If I wanted, I can keep adding more ICs (up to 8 total or 128 IOs!!) as needed just as long as I set a new unique address to each IC when using I2C.

I have also used this IC with an LCD display that uses up IOs quickly.

73,

Mike, AB1YK

A Winter’s Night Visit to MakeIt Labs

Let me begin by setting the scene. Imagine bone-chilling cold…It was colder. I was going to wait outside for Fred (AB1OC) and Jamey (KC1ENX) but the biology supporting my internal survival mechanism had other plans.

Bravely, I opened the door and was quickly greeted by John Bottoms. Interesting name, but a cool guy. We chatted for a bit and it turns out he’s working on embedding AI into VR…I think I have that right. He quickly pointed out that Thursdays are MakeIt Labs (see their web site)  busy days since that is when they host their open house. I did see all around me many people working viciously on their projects. Truly, it was maker heaven.

Not long after, Fred and Jamey showed up and we were ready to begin our tour. Well, almost ready. There was a brief, but awkward exchange among two of the volunteers about who would be giving the tour. I was starting to wonder why it was so long and drawn-out. Odor-eaters in my shoes? (Check), Deodorant applied? (Check)…so it couldn’t be me. Eventually, the two fellas realized a better alternative to suit both their agendas was to elicit the help of a 3rd fellow. That fellow was Doug; he’s good people.

Machine Lathe at Makeit Labs
Machine Lathe

Doug began by taking us into the garage. Man, you all have to see this place. Woodworking shops, machine shops (including lathes and CNC machines), a litany of other heavy power tools to make the biggest kid drool), a plasma cutting machine, a mechanic’s shop to bring your vehicle to tune it up — change the oil — or add nitrous. This. Place. Was. Awesome.

CNC Plasma Cutting Table at Makeit Labs
CNC Plasma Cutting Table

Fred was definitely familiar with the tools and instruments there. Jamey and I looked awed but bewildered. During our combined awe-strike, Fred found himself in a conversation with another knowledgeable gentleman named Andrew about plasma cutting through steel. It began harmless enough. They were telling each other about the thickest piece of steel they ever cut through. But soon, you could tell the other could not be outdone. By the end of it, I swore I heard tall-tales of karate chopping through 4 ft. titanium able to withstand a nuclear strike. All pretty cool stuff. (I may have embellished a little)

CNC Vertical Milling Machine at MakeIT Labs
CNC Vertical Milling Machine

We continued the tour to the electronics portion of the lab where they had 3D printers (and another one in color), a spare electronics parts room, networking stations, dudes flying around mini-drones. We also saw they had a fabric station where folks could come in to sew. I was surprised there wasn’t a line for this. Making blankets seems like the right thing to do currently.

CNC Laser Cutter at MakeIt Labs
CNC Laser Cutter

We saw multiple conference rooms available, a room for the FIRST robotics team they adopted, office space for folks with start-up companies — something for everyone.

Laser Cut Wood and Polystyrene Projects at MakeIt Labs
Laser Cut Wood and Polystyrene Projects

By the conclusion of the tour, we got to meet a member of their Board, Bill. (Hi Bill!) This guy was definitely on board with bringing amateur radio to the masses. He liked our ideas of setting up for Kid’s Day (or some variant of it), of our near-space balloon project, teaching license classes and/or intro. to amateur radio courses, and even helping us advertise before we arrive. I think he saw the strong parallels between what they do and what we do. This could truly begin to be a very useful symbiotic relationship.

So with our visit over, I would recommend to those of you who have not had the pleasure, get yourself out to MakeIt Labs. If you have questions, please contact me, Jamey, or Fred. (Fred became a member tonight, so he knows the secret handshake). I think if you have ideas, projects that you’ve always meant to get done but haven’t found the time yet — this is the place for you. I think after you see this place, and if you were on the fence about getting involved in the Club’s Youth Outreach effort, I think you’re going to be all in after visiting.

See you on the air,
Brian, AB1ZO

Home Brew a Variable Capacitor

I was looking for variable capacitors for my home brew projects that do not have high costs.  I did a Google search and found the following links:

http://www.qsl.net/n4dfp/buildcaps.html

http://www.eham.net/articles/15975

The nice part is that you can make changes as you see fit.

I made some changes and modeled the design in SolidWorks.

Homebrew Variable Capacitor in SolidWorks

From SolidWorks, I made a sheet layout in FabriWIN.  you can see spacer washers cut out of the “scrap”.

Homebrew Variable Capacitor

My .030″ aluminum rotors and stators only needed some deburring from the CNC turret punch press at work.  I also did not make the spring loaded rotational contact.  I just attached a ring terminal and some wire to the rotor shaft.  Below is a cap that I will be testing in a home brew antenna tuner.   I will increase the air gaps if I find it arcing.  I’m not sure that will happen at QRP levels. The knob is an old plastic gear from an old printer.  It prevents my fingers from changing the capacitance value.

Homebrew Variable Capacitor

73,

Mike (AB1YK)

Radio Amateurs Developing Skills Worldwide