I bought some wire wrapping wire about 3 years ago. I didn’t make much use of it because it ultimately didn’t seem very practical. soldering was the way to go. But lately, I’ve been thinking about it more seriously.
Pros and cons of wire-wrapping vs soldering
Wire is cheap. I use 30AWG rainbow wire wrap. I don’t remember where I originally got the wire from, but you can buy 280m of the stuff for £6 (as of writing) from thepihut. Ancillary costs, like the use of female headers, stand-offs and screws can also be eliminated.
Ancillary costs are also reduced. Wire-wrapping also eliminates You also save on additional components like female headers, which are no longer required.
It looks neater. The way I solder, I put the wiring on the top side of the board and feed the stripped lead through to the bottom. This looks unsightly, especially the way I do it. With wire-wrapping, the underside of the board is wired up.
The finished result is thinner. Nearly all of my components have male connectors that point downwards. To create a soldered board, I solder female sockets to the board. The male pins then slot into the female sockets. So you have components sticking up a few centimetres from the board, which looks a bit ugly. You then have to think about securing the component to the board for stress purposes. Components tend to wobble about, otherwise. Using wire-wrap, I push the component all the way through the board. There is usually sufficient headroom on the male connectors to do the wire wrapping.
Securing components is a little easier. Components are likely to have mounting holes. If you use soldering, then the holes are raised above the board if you use female connectors. With wire-wrapping, you can take advantage of the mounting holes, too. Use a length of wire and feed it through both the hole and two holes on the stripboard. Twist the end of the wires together on the underside of the board. the components should then be fairly secured in place due to the fact that the component is flush with the board. You can even use this technique when there aren’t mounting holes. You can wrap the wire over the component. Maybe that’s not as elegant, but it does not look unsightly.
Boredom works both ways. The good thing about wire-wrapping is that your stripboard remains in a pristine state. If you’re bored with your circuit, you just remove the wires. You haven’t committed the board, headers, or more expensive wiring. The downside, though, is that you can’t borrow components from the board. I often do this with my projects. I don’t use all the projects all of the time, which means I can take components from one soldered board and put them in another.
Mistakes are easily corrected. I am a bit of a duffer when it comes to wiring. It’s so easy to get the pins mixed up. Using wire-wrapping I can easily rip the bad wires out and start again. With soldering it’s more of a fiddle.
Layouts can be slightly more compact. If I solder, then I require generous space between components to connect wires that lie on the top side of the board with the pins on the underside. With wire-wrapping, the components can be bunched together a little more. The connection can be made more directly. Additionally, wrapping wire is thinner and more flexible, making it a little easier to work with.
Some components don’t work well with wire-wrapping. Things like buttons, DIP sockets, integrated circuits, anything with female headers won’t play nicely with wire-wrapping. The male connectors aren’t long enough. Maybe this could be mitigated by creating a custom module on a separate stripboard, but it’s not an idea solution.
I decided to create a magic 8-ball simulator. I wanted to incorporate a buzzer and a tilt switch into the project. The idea is that you would shake the device, causing it to buzz. When you stopped, the simulator would present a new prediction. Unfortunately the tilt switch proved unreliable so I settled for just having a uC (microcontroller) and OLED display. To make a new response you just pressed the reset switch on the uC.
I used a Pimoroni Tiny 2040 uC, which has a Raspberry Pi RP2040 chip on it, but is the size of a postage stamp. I chose a 32-bit high OLED display to keep the size down. It’s only two components, and fits on a 7cm x 3cm stripboard. It is powered by USB, although you could probably use a cell battery.
Pictures of the wire-wrapped board are below.
The code is available on my github account. You should download the whole repo though, as it depends on a component in the parent directory.
It was a fun, quick, project.
In search of the perfect modular system
Wouldn’t it be great if we could dispense with breadboards and just use some plug-and-play solution? I’m trying to imagine how such a system would work. I discovered grove connectors a few months ago. I can’t say I like the idea much. The fact that the pin pitch isn’t that of a standard stripboard makes the idea largely unworkable in my view.
I recently bought some connecting pin housers. I wish I had bought some ages ago, because they save a lot of fuss when it comes to connecting a row of Dupont wires.
I’ve not really come up with a good solution to the problem of creating a modular, convenient solution. My two ideas centre around the following:
- 1. “Eurorack” concept. A Eurorack was originally specified in 1996 to create modular audio synthesisers.
- 2. Giant Eval board.
- The key feature of the Eurorack standard is that it specifies the height and mounting positions of audio modules. This means that casing units can be built to that spec, and modules easily mounted onto them. Power is supplied to the back of the module though standard comments. Modules usually contain female banana-type sockets so that they can be connected to other modules in flexible ways.
My own adaption of the idea is to specify the ordering of things like SPI pins. Each “module” would be some standard stripboard size on which a component, or maybe a group of components, were mounted. Male connector pins would stick up from the topside of the board.
All modules would be mounted onto a piece of wood. My best idea so far is that you’d drill holes into the wood where the mounting holes for the stripboard are. Pegs, in the form of matchsticks or shish kebab sticks, or maybe nails, are inserted into the wood to locate hold the module. Perhaps not the most secure solution, though. Maybe adding a screw hole would do it.
Modules would then connect to a breakout board housing an MCU, which broke out SPI, I2C and other protocols in a standard layout. You’d hook components to the MCU using Dupont cables. this should make hooking up components much simpler.
My alternative approach is to get a large stripboard, and plonk an MCU on it. Components are then added to the board as needed, and connected via wire wrapping. so you end up with a kitchen-sink of components, all ready to go.
I’m not really sure which method is best.
Anyway, that’s enough pontificating for now. I’m off for a walk.