- A DIP40 chip, specifically, my PIC18F452 microcontroller, takes up too much space on a single breadboard.
- It can be easy to mix up power and ground.
- I hate prying large ICs out of breadboards.
- Most importantly, carrying around a raw breadboard with a project on it is a pain.
A “MEGA Multi Tackle Carrier Bait Box” can be used to carry a pair of solderless breadboards, spaced such that there is an airgap terminal strip spaced at .600 inches, the sizing for the larger DIPs, like the DIP40s. A binding post pair can be prewired to allow the use of banana plugs to power the board as well.
- 1 “MEGA Multi Tackle Carrier Bait Box” from Walmart
- 2 solderless breadboard bus strips and 2 solderless breadboard terminal strips
I used Jameco P/N 20722 and Jameco P/N 20669. If you go this route, make sure the power bus strips are removable.
- Double banana binding posts
I used something from Radio Shack, identical to Jameco P/N 125196
- Some 20 AWG wire, black and red
- A Dremel or other cutting tool
- Optional: 40 pin ZIF socket
I used Jameco P/N 104029. If you go this route, you will need a DIP40 socket for the ZIF as well.
The removable container inside of the MEGA Multi Tackle Carrier Bait Box has permanent horizontal dividers, and removable vertical dividers. The benefit of this is that I can store related components right with my breadboard. The downside is that a double-sized breadboard won’t fit with the fixed horizontal dividers.
This is easily solved with a Dremel.
After the Dremel job is finished, it looks like this:
At this point, I separated the power rails from the breadboard, put a power rail on one side of each of the two terminal strips, and separated the two breadboards using DIP40 sockets between the two breadboards. This spaces them correctly so the middle is a terminal strip for DIP40 spacing. The next picture may explain better. I then positioned them on the inside cover of the box, so that they would fit in the space I dremeled out. I made sure to account for the binding posts by giving the breadboard room on the top and bottom.
I pushed the ZIF socket into the DIP socket, and pushed that into the breadboard. After the sticky backing from the breadboard was removed, the breadboards were attached to the inside cover.
Open, it looks like this:
Closed, it looks like this:
It is obvious at this point it has a generous amount of room for prototyping while allowing the top to close.
The next step is attaching the binding posts to the inside cover. I did not want to drill through the cover. When the cover is removed, and it isn’t being used as a carrier, but instead a prototyping board, I wanted the plastic to lay flat. This meant I needed to modify the binding post piece.
I did this with a Dremel. Cut down two of the plastic holes so the nuts will end up flush with the bottom plastic piece. I only used one nut for each hole, and I only need to cut down one side.
The next picture shows how both holes should appear. The black holes should look like the left side, and the red holes should look like the right side. The right side was not modified, but the left side was.
The next step is to cut down both of the pegs so they will end up flush with the plastic.
Take plenty of precautions with your Dremel. Do not get metal shards in your eye, or anywhere where they will cause damage. I do not advocate cutting metal with your Dremel ever, especially late at night in the middle of a residence hall (read: dormitory).
This picture shows a comparison between an unmodified peg and a cut peg.
The next step is to etch the bottom of the black piece, so that it will adhere better after the epoxy. Then I assembled the binding post pair.
Mixing up some epoxy, I smeared some on the bottom of the binding post, and also the side. This allows the epoxy to both bind to the plastic on the bottom, as well as the plastic on the breadboard. The first time I attached it, I only put epoxy on the bottom, and after a few days, it snapped off.
At this point it looks like this:
I then attached appropriate colored wires to each bus line from the binding post pegs.
The end result looks like this:
Another benefit of the carrier is that it fits directly in the box with the rest of the electrical engineering stuff, being both transportable to lab, and also directly usable in my dorm.
An annotated set of these pictures is available as a Flickr set at http://flickr.com/photos/adamwolf/sets/1167654/.
Possible extensions to this project include power protection. A zener diode across the power terminals or a tantalum capacitor in series with the power could provide cheap protection against inverted polarity.
Send me your questions or comments!