Hello and welcome to weekend projects. I’m Farhan and I’m Naveed. And this week we are going to show you how to take something like this and turn into something like this, a printed circuit board. A PCB. So the first thing you need to do is make up a circuit. How do you do that? I made up this one myself but you can find circuits online at various sites like discovercircuits.com or many others. Why would we print up our own circuit boards? Why? There are a number of reasons why you might want to have a printed circuit board as opposed to a bred board. Number one, you can get much higher density with printed circuit board. Number two, it’s a little bit more reliable and you have a finished product that’s not going to fall apart and wires pop out. And number three, it’s good because you can use, you can have very precise controls with the parts that you’re using and have odd shaped parts that won’t fit on a bred board. The first part of making a printed circuit board is to define your circuit and this is where you specify what parts are on the board and how to connect them with each other. Once you have your circuit defined then you lay it out on the board. And that involves taking this and making it into something like this. Eagle cat has little bit of a steep learning curve but theres tutorials online that will walk you walk you through it. Once we have our circuit defined, its time to go ahead and get it on the circuit board, to do that we’re going to use the toner transfer method. Toner transfer is basically where you print out your circuit pattern using a laser printer and then transfer the toner that was on the sheet of paper on to a sheet of copper. There’s a lot of different schools of thought on toner transfer. We’re using the method written up by Thomas Gutti and found online. One of the most important things about toner transfer is the choice of paper that you use. This is a very popular choice, staples photo basic gloss. A lot of people had a lot of really great success with this, including myself.
The first thing we do is cut our board to size. I like printing out an extra copy of the pattern using that as a template. The dust on this stuff is toxic dust. So, you want to make sure you wear a respiratory protection.
To prepare a board, we rough it up. We file down the edges. We clean it with a little bit of acetone. Do this with a scotch brite pad or artificial steel wool because real steel wool will rust and mess things up. Warm up your iron to the hottest possible setting. Use about 30-40 pounds of force. We really lay into this thing. Now the plastic of the toner is attached to the board and the paper. We want to get rid of the paper. so it’s just attached to the board. So, we are going to soak in water. After about 2 minutes of soaking, we’re going to peel off the first layer of paper, exposing the paper that’s underneath. If you don’t do this, you can let this soak overnight and the water still won’t penetrate all the way through. Once it’s soaked for long enough, you want to take it out and rub it with your fingers to get all the paper bits off.
Then, its etchant time. There’s lot of different types of etchant. But the one that we are using today is ferric chloride which is the most common variety you can find in your local electronic store. Don’t drink this stuff. It’s toxic. One you get in the etchant, you want to keep the etchant moving over the surface of it. Agitated. Don’t leave it in there for too long. Take it out when the copper that you want gone is gone. Once you are done etchant, we use acetone to remove the existing toner to reveal the shining copper underneath. To drill the holes in our PCB, we’re going to use carbide bits and a dermal drill press. These bits can be got for relatively cheap on EBay. The 0.035 inch drill bit will take care of most of your needs. This is an optional step. I would like to print out a documentation layer that you can put on the top side of the board, to give me a guide when I’m soldering the parts on.
Now, we have got our board all soldered up. All that’s left is to cross our fingers, turn it off and see if it works. Great. That was your turn. Go ahead, design some circuits print up your own boards and then you can go ahead and make something like this. We will put the designs on the PDF and I’m going to put this on my bike and you can also make something similar to spruce up a birthday cake or you can hang around town in order to use your local law enforcement. Whatever you do make sure to take pictures of it and put them in the next Flickr pool. Go make some circuits. Have a great weekend.
