Electrical engineers get to a point where they need to test the actual performance of their prototypes. Unfortunately here in the Philippines, there are virtually no PCB fabrication houses that offer fabrication, assembly, and testing. And hence your overly used and abused, stained, burnt breadboard would be the number choice when prototyping.
However, a breadboard does have some limitations. You’ll have limited space, limited connections, limited current capability, I could go on but I think you get the point, right? Not to mention that the connections are loose and will give you very trivial problems when debugging and very susceptible to static interference when you bring your hand by just a couple of millimeters to the “flying” jumper wires. That’s why I never use breadboards for prototyping. I repeat, NEVER!
However, if your circuit doesn’t have any RF or fast-changing digital signals or small analog signals, then it will just be fine to use a breadboard.
The second option would be a perf board (short for perforated board). This is a pre-drilled board with or without connections similar to a breadboard. It varies is different sizes and could come in single- or double-sided. Some quality perf boards are tin-plated (with plated thru-hole for double-sided ones) to protect it from corrosion and are made of FR4 (fire-retardant) resin.
But the best and most professional method to fab your circuitries is have it in a PCB. And again there are several methods that you can do this, either manually or digitally. And over the years, I have tried almost every method out there. You name it, I’ve tried it. Here are some of it to name a few:
- Manual routing using a permanent marker
- Manual cutting of the negative layout using scotch tape
- Using a vinyl cutter or sticker
- “Manhattan Island” style for simple RF circuitries
- Toner transfer using a flat iron and photo-paper (any glossy paper)
- Toner transfer using acetone and photo-paper (any glossy paper)
- Laser cutting of spray-painted copper clads (Computer Numeric Control)
- Direct laser etching of copper clads (Computer Numeric Control)
- Milling and engraving (Computer Numeric Control)
- Presensitized (photo-resist) boards
- Professional PCB fabrication and assembly (offshore)
- Silkscreen method
- Toner transfer using a flat iron and a heat-activated toner transfer paper
Out of the 13 methods listed above, the last one is what I personally prefer and is what I use very often for prototyping at home. It gives me the best results every time granting that the size of the board is not larger than of the flat iron since it needs constant pressing during the process.
Unlike the photo-paper, peeling the heat-activated paper is so easy that it requires no effort at all. It just comes off easily and leaves no residues. No need to brush or rub any paper left after peeling and less chances of correcting the imperfections with a permanent marker. If you are to have a large board however, better to use a heat press machine.
So here is how I do it:
Step 1: Prepare the PCBs and the paper
Cut the PCB beforehand to the size of the design. Use a cutter to score it or a cutoff wheel and then sand the edges and the surface of the copper clad to remove the corrosion and also a rougher surface will make the toner adhere better.
Make sure to print the layout using a laserjet printer since you’ll be dealing with toner and not inkjet. Cut it also size and clean both copper clad and the paper with 99% isoprophyl or denatured alcohol (make sure it has no moisturizer).
Step 2: Ironing the layout
Pre-heat the flat iron to its maximum while aligning the paper to the copper clad. When it is ready, press a portion of one side so it will stick and won’t move when you go on with the other side. There is a chance that the layout will deform when you press everything at once since the paper is slightly rolled and not perfectly flat due to the printing.
Use the edge of the iron to press on the paper. Don’t just press it flat with all your weight. You’ll have to reach every surface area. You’ll then know that it is ready when you see the whole layout become visible.
Step 3: Peel the paper
Let it cool for quite some time before submerging it in lukewarm or cold water. The water here is not really necessary but it will help in releasing the paper from the copper clad.
Step 4: Etch the pattern
Using Ferric Chloride is the most popular etchant to use for PCBs. However, I find it expensive and its efficacy varies with every store you buy it from. Maybe because it is recycled or has lost its efficacy over time? I personally just don’t like using it since it could stain and takes a relatively longer time to etch.
Some use salt and vinegar also as etchant but my personal favorite is using one part Hydrochloric (Muriatic) acid and two parts Hydrogen Peroxide. It etches really fast and you’ll see the progress since the solution is clear. Disposing it is easy. Just put a few tablespoons of baking soda to neutralize the acid before pouring it down the drain.
If you are making a double-sided PCB, use a plastic slide as standoffs so that the etchant can flow freely at the bottom and also to prevent the layout from being scratched off during agitation.
Step 5: Drill the holes
This is probably the most boring part. That’s why I use surface-mount components as much as possible for all projects!
Anyways, using a drill press is best so that you would get perfectly perpendicular holes. Make sure your drill bits are not worn out since abused bits would just wobble around the hole and remove the copper trace without even drilling the board. To prevent that, use a center punch to dent the board and that would help the bit to lock on to that and prevent wobbling. Just take your time and before you know it, you’re done.
Pro tip: Drill first before removing the toner with acetone. This will protect the copper from corroding and scratches during drilling.
Step 6: Protect the copper from corroding
Since liquid or powdered tin is not available here in the Philippines, and electroplating is not worth the hassle, just put on a spray of electrical lacquer to prevent it from corroding. It gives good electrical isolation and protection from moisture also.
You can still solder on it and even if you won’t finish soldering the components today, you can continue anytime you want since it is protected from air. You know how frustrating it is to solder on a corroded copper, don’t you?
However if the project calls for a mass production and professional look, or you can just always send your design files abroad, pay for their services, have it just shipped to you, pay the Customs taxes and duties, and wait for it to arrive, and/or pray if you receive a call from the National Telecommunications Commission saying that your board is not allowed to be used here in the Philippines.
The plus side of having it done professionally are plated thru-holes and vias, tin-plated, solder-masked, with silkscreen, precise track impedance (for RF impedance matching to external or meander PCB antenna), and much more.
Can you see the “flying” potentiometer? That was flying because I was such a genius during the design stage!
Wrapping it up!
Are you planning to fabricate your own PCB at home? Or have you used any of our methods mentioned above? Let us know in the comments section below!