Building on a Propeller Project Board USB
David Betz
Posts: 14,511
in Propeller 1
I have a simple circuit I'd like to build that uses a few resistors and a single 8 pin PDIP. I'd like to build it on a Propeller Project Board USB (https://www.parallax.com/product/32810). My problem though is I'm not sure how to work with this kind of board. I've used boards like the Circuit Overlay Board (https://www.parallax.com/product/32999) that pretty much mirrors a breadboard. How do you work with a board that has plated through holes but none are connected to each other? It seems like it would be awkward to solder a PDIP onto the board and then try to attach wires to the PDIP pins.
Comments
When you get the hang of the hardware stuff and tire of hand-wiring boards you can etch PCBs at home. Yes, I still do this when I need a board today (so long as the board is not too complicated). I use a product called PCB-Fab-In-A-Box.
Here's a little board I built for a Cylon-themed dress for San Diego Comic Con.
Under the Propeller Mini is a TC4427 and a couple resistors.
You can easily get two wires on a pin or resistor lead wire. Sometimes I'll daisy chain by stripping a 1" section in the middle of a wire sliding the insulation towards one end (the shorter one), then stripping 1/2" from that end for the next connection. I'll double over the 1" area and slip that through the adjacent hole to wrap around the PDIP pin. It helps to have a simple wire-wrap stripper and a sharp small diagonal cutter.
If you don't have wire-wrap, 26G or 28G solid wire will work, just not as nicely. You'd like insulation that'll fit through your board holes. If you need more than one wire on a pin, use two adjacent holes next to the PDIP pin for the wires.
There was also a button in her waistline so she could cycle the animation states. Yes, that's a strip of WS2812 LEDs across her chest.
The are two problems with this second approach: 1) There is a fair amount soldering. Veroboards aren't difficult to solder, but they are certainly not as easy to solder as the Overlay Board, and 2) It is more difficult to share the design with others. Everyone can buy an Overlay Board... relatively few people have even a cheapo CNC machine. So... if it is just for me, I frequently go the Veroboard/CNC route. It is fun and productive. If it is for the community, I try my hardest to stick with an Overlay Board or two or three:)
The reason I do it this way is that stripping a short piece of insulation off of the end of wire-wrap wire is difficult -- or at least tedious -- using the usual wire-wrap stripper. This is especially true if the piece of wire you're trying to strip is very short. Plus, there's zero waste with this technique.
-Phil
That kind of board with uncommitted plated-through holes is the perfect proto board to use. I either bridge adjacent pads with solder itself or just use stripped wire-wrap wire taking the track to exactly where I want it to go. Of course you use ww wire to connect point to point but stripped and tacked to pads it's a great track.
btw, here's a P2 proto where you can see I've used a bare wire as a track. I really really hate "tracked" protoboards with a vengeance, especially single-sided, as the cutting of the track is problematic and leaves burrs that may short etc.
The shoes look to have LEDs too. Anything special there?
My experience with wire wrapping goes back to the 70s when I usud it for a while. From what I remember about it was the wire insulation was some pretty tough stuff, like Teflon. But also you didn't need to strip the wire, the post that you wrap to cuts into the insulation to make the connections. Not sure what the modern day version is though.
There was no time to update the shoes -- we did that whole project (including me designing and etching a PCB) over a weekend). Jinyo and Victoria (from the show "Heroes of Cosplay") bought several Propeller Minis so we could do the shoes, too, but time ran short. What's in the shoes is a cheap LED string from All Electronics.
I built some interfaces in the early 70's as well, and IIRC the wire wrap insulation was Kynar or some similar name. That was the most common wire wrap insulation, but was not practical to use when soldering the wire wrap joints. Teflon insulated wire wrap wire was harder to find and more expensive but stood up well to soldering temperatures, although it was very difficult to strip without the proper tool.
http://www.pcbfx.com/main_site/pages/products/starter_kit.html
Kynar sounds about right. I remember trying to repurpose the wire when I got out of wrapping, and the insulation didn't hold up to heat very good at all. The modern product that has to be stripped first, as Peter said holds up to heat better.
If you need to strip any kind of wire including this stuff you can just use your side cutters but from the back of the cutters with your middle finger in between the handles to regulate the tension. The back of the cutters will dig in nicely at 90' to the wire rather than what I see everyone else struggle with when they strip with the cutters in the "traditional" manner (moving V of cutters upwards rather than inverted V upwards) if you know what I mean.
btw, I have in the past used that coated "Vero wire" with the wiring pen and guides to build boards where direct soldering will melt the insulation coating but that stuff is thin and really needs the guide rails to keep it all together.
EDIT: I think I will have to post a video showing how to strip and solder this wire, but it is the best way I know of making a reliable hand wired prototype. You may have noticed that I also used copper tape for a ground bus just where I want it
That wire definitely takes up a lot less space, and less confusing to trace. I will have to place an order soon.
Sorry about the rhyme.
EDIT: Not to mention less solder, less weight, less fumes to dull your brain.
I know the pain, I thought I had decent plated through hole proto boards, nothing made here.
Anyway I lifted the pads a couple pads on some rework, just go to the next pad., if needed.
Parallax through hole prototype boards are heavy duty, under Peter's process they would last forever. They could be reworked or repurposed at will.
Don't you find the Prop-plug male header on the Propeller Mini gets int the way, there must be a special concern to trim leads as short as possible or, OUCH!