I assembled for my grade 12 Computer Engineering final project. The goal was to fabricate any circuit that used a 555 timer IC chip. I liked the way LED cubes looked and perhaps the challenge of it too, so I went with arguably the most complex one. Making homemade/DIY PCBs had its pros and cons.
Pros: quite a bit of learning from it, more hands-on, pretty affordable
Cons: copper clad boards could burn easily, takes time and some tools
As previously mentioned, the copper clad boards burn pretty easily, so that combined with the thin layer of copper which would oxidize kind of easily caused a lot of the copper to come off. Hence, the less than hobbyist and far from professional soldering seen in the later photos. I recommend using a 45W soldering iron since 60W (the one I used) was likely too hot at times. Another problem I encountered was that the diagram I'd followed didn't ground the circuit completely so it ended up not working once it'd been all soldered. The 555 chips used when the pin 11 of the 4020 wasn't grounded all got fried and became unusable. But rest assured, this one works well even after three years of it being made.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Bill of Materials (BOM)
- 5 x 7 cm One-sided Copper Clad Board
- Transparency Paper
- 3mm LEDs (x27) ~ (can be any color)
- Female DC Barrel Jack
- Heat Shrink Tubing
- 16 DIP IC Socket
- 8 DIP IC Socket
- 555 Timer IC
- CD4020 Binary Counter IC
- Thin Sharpie Pen
- 33k Ω 1/4W Resistor
- 10μF 25V Electrolytic Capacitor
- Steel Wool
- Ferric Chloride
- Needle Nose Pliers
- 12V battery or 12 Power Supply rated for 2A+
- 45W Soldering Iron (higher power rating may be used but burning the board will be more likely)
- Lead Free or Lead Solder
- Rosin Flux Paste
Step 2: Creating the Circuit Diagram
Although Fritzing has been not seen updates to their program since 2016, the latest release is sufficient in us making our PCB file.
The design was based on this link: 3x3x3 Cube using 555 Timer. The 555 chip wasn't grounded properly so I added the fixed image as the first photo. The second image is the real circuit used to get the cube working nicely. The other two photos at the end are just sample photos of how the circuit may look like on Fritzing.
Step 3: After Removing the Excess Copper
After removing the copper off of the copper clad board, the PCB should look roughly like this. Now we have to remove the sharpie/ink from the copper of our main circuit. We'll be using some light steel wool since sandpaper would be a bit rough. Once that is done, carefully use an x-acto knife to cut any bridged connections which are out of the ordinary and not following the proposed circuit diagram.