Introduction: My Top Ten Most Useful Breadboard Tips and Tricks
There's 6 inches of snow on the ground, and you're cooped up in the house. You have momentarily lost your motivation to work on your GPS-guided metal-cutting laser. There haven't been any new projects on your favorite site which have piqued your interest. What to do with yourself?
Well, how bout pimping up your breadboard and turning it into a lean, mean, digital-development machine?
This is a short list of the most useful breadboard tricks that I have picked up over the years. Hopefully there's something in here that you will find useful which you haven't already thought of.
Ok, I don't really have 10 tips to share; it just makes for a catchier title. :P
Step 1: Power Connector
Well, the first thing that a breadboard needs is power. Many breadboards come with binding posts. This is fine if you care to use them. But you still have to plug the wires into the board. I have messed this part up on occasion, mixing up the power and ground wires. Even though rare, this has usually resulted in rather annoying and/or expensive consequences. The solution I came up with is to always use 3-pin connectors.
See the following picture. It's made from SIP header pins and protoboard. After point-to-point wiring, it is covered with sculpting epoxy.
Step 2: Power and Ground Buses
There are times where it would be useful to dedicate some of the power and ground rails to different voltages. For me, this occasion has yet to arise. I decided to connect them permanently to reduce some of the clutter.
All you have to do is unscrew the breadboard from the backing, if it has one. Then cut away a strip of the foam backing with an Exacto knife. Next, solder the power and ground buses with some fine wire. Then cover with tape and screw it back onto the backboard.
Step 3: LED's
LED's are commonly used in the debugging/development of most any electronic circuit.
Well, these breadboard-friendly LED's aren't quite as quick to make as bending around some leads, but they are indefinitely reusable and will save you a lot of space on your breadboard.
Because they have a current-limiting resistor built-in and the lead-spacing is 0.4", they plug directly between your power/ground rail and the main breadboard section. And even better, they can be stacked side-by-side.
I used 0.03" thick single-sided pcb, 3mm LED's, 240R surface mount resistors, and SIP header pins to make these. The only trick is to leave the pins in the header until after you have soldered them, in order to preserve the spacing. And to get them to stack side-by-side, I ground the sides of the LED's a bit with a Dremel.
Here's a video showing how I made them:
Step 4: Buttons
Buttons, buttons, everywhere.
The ubiquitous 6mm tactile switch is another breadboard staple. When you need only 1 or 2, you can just stick them in the breadboard. But try using more than that, and you'll soon have buttons popping out by themselves all over the place, in addition to growing a nice plate of spaghetti.
The simple tactile switch's most common role is to provide a digital input by temporarily connecting an input pin to either the ground rail or the power rail. By making a button array, you can plug the ground/power rail in just once, and will also have a greater density of buttons that won't fall out. You can make your button array up to 3 buttons deep and still take up the same number of breadboard holes... but I find 2 rows to be a more convenient size.
Step 5: Switches
Sometimes it's useful to have a small switch rather than a push-to-make button. Most switches will not fit into a breadboard. A DIP switch array fits nicely and also happens to have 0.3" by 0.1" spacing. Super!
Step 6: Pullup Resistors
Anyone messing with electronics will be familiar with pullup/down resistors. It wasn't so bad in the good old days when 1/4 watt resistors had nice sturdy leads on them. Due to the increased demand for copper, these parts are now made with skinny leads that don't hold up to repeated use as well as they used to.
These pullup resistors are made the same way as the LED's and will last indefinitely.
It's also nice to have some 10k bussed network resistors on hand, for when you need to pullup an entire row of IC pins or buttons!
Step 7: For My Fellow PIC-heads: Breadboard With Built in ICSP
Microcontrollers are being incorporated in a growing number of DIY projects. During the development process, a chip may have to be reprogrammed many times.
I don't know if the same thing applies to AVR's, but most every 8 and 14-pin PIC (as well as many of the 20 pin ones) share the same pinout for the programming lines. So I have dedicated a breadboard just for development of these PIC's.
The technique here is the same as that used to connect the power/ground buses. After peeling away some of the backing, you can permanently wire your programming connections and port them out to a standard header. You can also connect your power and ground pins to the appropriate rails and add a chip capacitor while you're in there.
You'll also notice some extra circuitry next to the programming header. Well, the same pins that are used for ICSP can also be used by the micro as normal input/output pins or other functions. If you are using those pins in your project, then you may very well have to connect/disconnect your programming cable each and every time you change and update your code. I have found, for instance, that the PICKit2 programmer holds the programming lines low when the programmer is inactive. Rather than put up with this, I have connected the data and clock lines through signal relays which are only closed when the programmer supplies power to the Vdd rail. The power goes through a rectifier diode so that when only external power is used the relays remain open. The HVP line doesn't get a relay to itself. Instead it is simply diode rectified, so that when it is not active it does not pull the MCLR line low. There is also a programming button at the top left of the board. This simple Instructable shows how I did that: https://www.instructables.com/id/PICKIT2-programming-button-mod/
*Edit: Since publishing this, I've been informed and have also personally confirmed that the Vpp line on a PICKit2 becomes high impedance when inactive, so it does not actually need to be diode-rectified for circuit-isolation; all I have achieved is to remove the ability of the programmer to do a hardware reset of the MCLR line (which hasn't bothered me so far). Oh, well.. I needed a jumper for my pcb, anyway, and the diode was the perfect size. :P
**update: wow, that method of clock/data isolation is sooo last year. Check out the latest pic.
Step 8: ICSP Hat
For non-standard pinouts, a simpler solution may be more desirable. Here's a simple programming "hat." It has 0.5" spacing, so it slips over a standard narrow DIP IC. It's point-to-point wired, then covered with sculpting epoxy. You can leave it in the breadboard, if you don't mind giving up the extra space. Then just plug the programming cable when necessary.
Step 9: The End
Well, that's it. If you have any tips you can share, I'd like to see them!