Culture / Edge / IoT

Off-The-Shelf Hacker: Hands-On Fast Prototyping

29 Jun 2019 6:00am, by

Producing a weekly Off-The-Shelf Hacker story is a bit of work. I write the pieces from scratch and have to shoot/edit the little video that goes with each article. There’s also uploading the copy to the content management system (CMS) with attendant edits and possibly scratch-built or heavily edited graphics. And, let’s not forget all the initial project development and trial builds that precede the actual article drafting. An OTSH story has a lot of moving parts and processes.

Consequently, I’ve discovered useful techniques and process that help me crank through the hands-on craftwork, in a fast prototyping environment. Writing the story is in the latter part of the project.

Let’s look at a couple of “shortcuts” I use for getting the job done before the deadline.

Breadboards, Jumpers and Modules

A lot of hardware projects start on a breadboard. These are the little 2-1/8 x 3-1/4 inch white hardware experimenter boards with all the tiny holes. They have a 0.1 pitch between holes, which coincidentally lines up with 0.1 pitch pin headers and discrete inline integrated circuits (IC). I still have a larger breadboard from college, that I use occasionally. Wow, that was many, many moons ago! I also have one small clear plastic, awesomely futuristic-looking breadboard, which is almost never used. It’s too hard to see if a wire goes in the right hole. I prefer the plain white ones.

ICs, transistors, resistors and capacitors plug into the breadboard to quickly create circuits. You can make your own jumper wires by stripping the insulation off of 22-gauge solid copper wire to connect components together on a breadboard. I used to make my own wire jumpers, back in the dark ages. You know ten years ago. For robust “temporary” builds, that use a lot of wires, I’ll sometimes make custom jumpers so I don’t have a rat’s nest of flexible jumper wires snaking around all over the place. The rigid wires also tend to stay in place better than the floppy 6 inch long jumpers.

Nowadays, you can just buy a bundle of pre-made male-to-male AND female-to-female jumper wires and use those to connect circuits together. Obviously, the male-to-male jumpers are primarily used on the breadboard. The female-to-female jumpers come in handy when making temporary connections to header pins.

Pre-made jumper wires, male (left) and female (right)

For prototyping, I usually attach modules together with strips of header pins and sockets, so I can take them apart and re-purpose them in other projects. Female jumpers work great to connect header pins to header pins, kind of like flexible breadboards.

On the other hand, when buying printed circuit board modules, I like to get them without installed header pins and sockets when possible. That way I can decide if I want to use the module strictly for fast prototyping projects or install it semi or permanently in a project. Once a strip of dozen-odd header pins or a pin socket are soldered to a printed circuit board, they’re very difficult to remove.

Two tiny DigiSpark boards, one with headers (left) and one without headers (right)

For example, if you need a robust project to demo at a bunch of tech talks, it’s much better to solder the modules together with wires, instead of jumpering. Jumpers tend to come apart when handled and you certainly don’t want that to happen right before you are supposed to go on stage. A lot of times I have a stock of pinned and socketed boards and a separate set of boards without pins and connectors. It’s a little more cash, but gives me the flexibility and is just the nature of the business.

Where’s the Part?

Organizing parts is a continuous process for off-the-shelf hackers. Commercial operations call it inventory control. We want to quickly turn out projects and yet be able to swap parts around as new ideas and projects materialize. Embrace the off-the-shelf mentality and keep marching forward.

I like to put smaller components in the opaque plastic parts boxes. You can get these at hobby stores like Hobby Lobby or Michaels. Search around in the bead and counted cross-stitch departments. Small, compartmentalized parts boxes are also available at home improvements stores like Home Depot and Lowes. They appear in the storage container department. Finally, in a pinch, you can use plastic fishing lure boxes from a place like Bass Pro Shops.

Compartmentalized small parts box

Static electricity damage is always possible with this type of component storage. Practice appropriate precautions using static discharge foam and bags. Modern components tend to be pretty rugged and I have personally had minimal issues.

As a matter of fact, on more than one occasion, I’ve pulled a Raspberry Pi out of my pocket, hooked it up to the projector, power and keyboard, then run my slides for a tech talk. How’s that for confidence in the hardware?

Don’t be scared to tape parts together. Hot glue is a little more permanent and rigid. Tape can be pulled apart or cut away, as needed.

For larger collections or bigger parts, I like to use 15 x 11 x 6 inch plastic containers with lids. I’ve even taken a few of these on trips to distant cities. They fit comfortably in checked luggage and can be duct-taped closed. They also stack well, so are easy to store in your shop.

One of the most important parts of a good storage strategy is the ability to remember where things went. For a lot of things, my memory is like a sieve. Oddly, I can usually remember seeing a very specific bolt or electronic component somewhere and then being able to go back to that place and find it. It seems to help to periodically browse through my various parts collections to keep the mental location index up-to-date.

I don’t really know how to tell someone about developing their “parts memory.” Sadly, I have to say you are on your own on this one. Do whatever you can to enhance your memory for parts.

Reflection

Two more quick things. Scotch tape and hot glue.

Don’t be scared to tape parts together. Hot glue is a little more permanent and rigid. Tape can be pulled apart or cut away, as needed. Readers have seen examples of both in past articles. Prototypes may not stand up to a lot of use or an unending schedule of demos. They do need to work when called upon, so adjust your “build” as needed.

Fast prototyping demands speed and results. Make it pretty later. Make it durable and rugged, only if that’s a requirement. You can always repackage and improve the design in subsequent versions and as you gain experience with your new gadget.

Get the current version working and the story posted on deadline.

Catch Dr. Torq’s Off-The-Shelf Hacker column, each Saturday, only on The New Stack! Contact him directly for consulting, speaking appearances and commissioned projects at doc@drtorq.com or 407-718-3274.

Feature image by DavidRockDesign from Pixabay.

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