This tutorial will show and tell you the steps I took to make my own printed circuit board for my wearable display project. There are many benefits of having a pcb: it can be quite small, it will fit into your project perfectly, its inexpensive. Before I get into it, this process is based on Tom Gootee’s Easy PCB Fabrication.
TIME & COST: This process took me in total around 5 hours, and cost around $50 for the components you need such as acids, solvents, etc. This cost does not include all the electronics and printer which I already had.
FIRSTLY: the first thing you will need to do is design your PCB. For large scale projects, it is highly advised you use some sort of circuit CAD program, but for small projects (like this one) it is quite ok to use a drawing program you are comfortable with (but preferably vector based). I designed my circuit below to-scale in Adobe Illustrator.
WHAT YOU WILL NEED: you will need the following materials in order to make your own PCB. I have included links and images for some but not all of these materials:
- Laser Printer or Photocopier (NOT inkjet)
- Special PCB paper (I used TTS paper from wiltronics)
- A PCB marker (important for touch ups, you can buy from jaycar)
- Household iron
- Plastic tupperware container
- Mineral Turpentine or Paint Thinner
- A blank copper-clad board
- Cleaning acetone-based solvent (I bought from dick smith electronics)
- Ferric Chloride (also bought from dick smith electronics)
- Scotchbrite scourers (artifical steel wool - do NOT use real steel wool type)
- Latex cleaning gloves
- Paper towels
Perform the following in order:
Please note: you should have already completed a to-scale drawing your circuit diagram before starting this process.
- Cut your copper board to the size you require based on your circuit diagram drawing. Once it is cut to size, files the edges down where you cut so they are level with the rest of the board. Now put on your latex gloves and use the scotchbrite scourer to scrub the copper board in orthogonal directions (up & down, back & forth).
- Once you have removed all scratches, dirt etc from scouring, spray the cleaning solvent onto a paper towl and scrub the board over. Keep repeating this process till the paper towl no longer becomes dirty from scrubbing (indication the board is clean).
- Now you will need to print your circuit using your laser printer, or print using an inkjet and photocopy. You cannot make a PCB from inkjet because it uses ink, not toner. Use the special TTS paper to print or photocopy your circuit, but make sure you print to the adhesive glossy side (note: you don’t have to use TTS paper, you can use regular or photo-quality paper but I have not tried this). Once printed or photocopied, cut out the area containing circuit.
- Turn you iron on to highest temperature but with no steam. It is good to empty out all the water first from your iron. Place the copper board onto a piece of heat resistent material (e.g. a piece of wood) with the copper side facing up. Place your cut-out printed circuit face down on the copper and press the iron down firmly on one corner briefly to hold the paper in place. Now place a piece of parchment paper (cardboard) on top of the paper (note: you don’t have to use parchment paper, but I found it gives best results when using TTS paper).
- Now, with the iron ‘very hot’, place in down flat firmly covering the whole area of the board. Hold this for around 1 minute pressing down hard and flat. Then begin to slowly move the iron around on the parchment paper over the area covering the copper board. Do this slowly and event giving equal attention to each part of the board. Go over it 3 or 4 times stopping regularly and pressing the iron flat over the whole area covering the board. You can go over again with the tip of the iron but still holding flat. Then finally hold the whole iron over the board area for a final 30 seconds.
- Now remove the iron and parchment paper. If you can see the circuit through the special tts paper, then you have probably done it right. Now quickly move the circuit into a bowl of hot water and let it sit gently for around 2 minutes. Then you can jiggle the bowl a bit to remove the paper, or do it your self gently. What you should see is the circuit is now stuck to the copper. If you find find that it didn’t stick to the coper, or it has mostly pealed off, don’t worry - just scrub it all off using paint thinners or mineral turpentine and start again from step 1. If you find that only a little bit has peeled off, do not start again, you can easily fix this by drawing over the missing area using your PCB marker.
- Now that your circuit is on the copper, it is time to Etch. Put on some protective goggles and keep your latex gloves on (you must wear latex gloves or your hands will become stained yellow). Pour some ferric chloride into a plastic or glass tupperware container (not in metal container or sink - it will be ruined!), pouring in just enough to submerge the board. Now place the board into the ferric chloride and let it sit for around 5 to 10 minutes. After this time, with the board still in the container, gently begin to scrub the board using a paper towel soaked in the ferric chloride. You will begin to notice the copper going away leaving the plastic of the board. Keep doing this until only the circuit remains. When done, safely dispose of the ferric chloride - NOT down the sink.
- Now pour some paint thinners or mineral turpentine into a small container and place the circuit in. Use a toothbrush to scrub away the toner and/or pcb marker. All that should remain then is the copper for your circuit - Congratulations your almost there! If you find there are some small gaps, you can fix these by filling them in with solder.
- Now you need to drill the holes where you will insert your components. I use a small handheld drill with a drill piece about 0.02 inches.
- Once all the holes are drilled, you can begin inserting your electronic components and soldering them into place. I like to use a multimeter throughout this stage to make sure parts that should be connected are connected, and vice-versa.
- Once you have finished soldering all the components, test your circuit to make sure it works. The circuit I have made here is a ‘shield extension‘ for my arduino micrcontroller. It connects ontop of and into the pins of the microcontroller (like a shield). This circuit is specifically for providing wireless connectivity to the microcontoller, and for connecting to and switching EL panels and wire.