Introduction: A Little Breakout Board for DIP ICs With Output Resistors
This is my first instructable! If you have any suggestions or questions, feel free to send me a PM.
After receiving my cheap (horribly packaged, that's what you get for being a cheapskate) 74HC595 shift registers from China a short while back, I decided it was time to give them a try.
I made a shaky first build on my breadboard but forgetting the resistors (thinking the current was perhaps internally limited by a resistor, silly me), got the IC really hot.
After building a second prototype I realized how much of a hassle it was to prototype with ICs on a breadboard, having to break out all the outputs with either wires and then connecting them to resistors, the LEDs and then ground, or jumping them straight away with the resistors, and how much easier it would be to have a small board with an IC socket and resistors built into the outputs to save me all the work of inserting resistors.
The fact that I wasn't sure if the ICs were broken or not meant I had to keep placing and replacing the ICs in my breadboard, with bent pins and frustration as a result.
I decided to make a little IC breakout board on a piece of protoboard with a socket for the IC, connectors directly connected to the IC and connectors connected to the IC through a 1kΩ resistor.
This would not only allow me to connect LEDs to the IC, but also to connect directly to the IC. While building the board, I realised it had another feature: the headers that are connected to the resistors can be used to pull the logic level of the IC inputs up or down! While 1kΩ isn't exactly the perfect value - I would generally use 10kΩ or 15kΩ - as it will draw/source a relatively large amount of current, it is still usable for high-power ICs or ICs with a high input impedance (the type of IC where a pull down/up resistor is specifically necessary) like CMOS chips.
Let's get started!
Step 1: Getting the Parts and Tools
We'll be needing:
- 6 8-pin headers. I prefer the breakable ones because they are more flexible in use, but you could use the set strips (like the ones found on Arduino boards), but you'd have to cut them up and sand them down (I've found this comes with a high failure rate). You can get these on the cheap on ebay (10 rows of 40 will set you back only a few dollars).
- 16 1kΩ resistors (You could use any value ranging from 220Ω to 10kΩ if you wanted, just know the higher their resistance is the dimmer your LED, but the lower their resistance the more drain on your IC when you use them as pull up/down resistors, I used 1kΩ as I had a roll of them lying around and they allow me to get the LEDs nice and bright).
- A piece of perfboard (Stripboard might be a better option since you wouldn't have to make solder bridges but only a few cuts instead, again I used perfboard because that was what I had lying around).
- A soldering iron and some solder (duh).
- Patience, the build will be very boring and repetitive, crank some music!
Step 2: The Build
Time to build this sucker.
Start in the corner of your board and insert the first header and solder it in place. Don't worry if you don't get it straight, it doesn't matter as you'll only be inserting jumpers here.
Next insert 8 resistors right next to the header (if you use a spacing of 4 holes per resistor it will fit on standard small perfboards like mine) and solder them in place, making sure to make a solder bridge between the resistors and the header (I like to solder everything in place first and make the bridge after). It's not a pretty method, and you could instead use the leads of the resistors as jumpers, but bridges are a bit easier and quicker.
use the above picture a
If your bridges won't form, make sure the joints you want to join are cooled down first as molten solder tries to form balls.
Now insert and solder in the next header and another one right next to it and bridge the pins of these headers with eachother and the resistors. The last inserted header will be one side of the IC socket. You could substitute for a regular IC socket here, but I find I always have a hard time removing ICs from their sockets without damage. The headers will provide a nice space below your IC to remove it from its socket.
Make sure you place the IC socket headers straight, or you might have trouble inserting your ICs!
With 8 pin headers you can only support IC with up to 16 pins. You could decide to expand the usefulness of the board by giving it more pins so it could, for instance, support an ATmega 328. To further enhance the board you could also add more rows of headers to support wider packages, but please note that the way I'm describing the build you will only have two rows of holes remaining on your perfboard, so you will either have to buy a larger perfboard or work in the other dimension of the board if you want to have more that two rows of headers for the socket.
After the previous steps, leave a space of two rows before you continue to repeat the instructions in reverse to create the mirror side of the board. The space will be necessairy for your board to support your general DIP packages like shown in the first image of this instructable.
Step 3: Sizing Your Board Up
After you've finished building your board, you might think there is an awful lot of empty space left.
Well you're right! Let's break of the empty piece of perfboard and keep it for a future project.
This is a bit tricky since your headers are relatively high. I recommend putting something rigid on the row where you want to break the board, and holding the part with your components soldered on it. This will make sure your precious project won't break.
Now you might say "I could've saved the trouble of breaking the board with components on it by breaking it beforehand!" and you would be right. But a small miscalculation as to where to break the board could ruin a good piece of perfboard. Or even worse, if you break the perfboard wrongly and don't realise it: you'll end up with a half-finished project and a full perfboard! Imagine the awfulness of doing all that work just to find out you have to start over.
Step 4: Testing!
Congratulations! Your little breakout board is done and ready for testing!
You can now prototype with almost all through-hole general purpose ICs and very easily and interface with inputs and outputs without needing to make a mess out of your breadboard with pullup resistors and current limiting resistors.
Step 5: Ideas
I built this board out of need for an easier and quicker way of prototyping with ICs, so it fits my needs.
You might want to expand on this instructable, though, by adding two LEDs to each pin with a resistor for real-time information about what's happening with your inputs and outputs, or adding a ground strip a few holes next to your series-resistor outputs so you can insert LEDs on the board itself!
A next version of this breakout board might be a custom made PCB with either or both of those options added in. The sky is the limit.
Step 6: Conclusion
I hope you liked this instructable and will find the breakout board convenient for your prototyping.
Step 7: Application
I've just built a little rig with my 74HC595 shift register IC connected to Arduino and the breakout board.
It works great! I couldn't upload a photo or video of it working because the LEDs are too bright for the camera to handle.