View All Posts
Want to keep up to date with the latest posts and videos? Subscribe to the newsletter
HELP SUPPORT MY WORK: If you're feeling flush then please stop by Patreon Or you can make a one off donation via ko-fi

Making Hard PCBs…

I saw this resistor box on the EEVBlog channel and noticed a comment from one the viewers suggesting that the PCB could be improved with a bit of DIY nickel plating - which apparently, according “Mr J.F. Christ” is “surprisingly simple” (you have to love some of the usernames that people pick).

It’s “surprisingly simple” - J.F. Christ

The box is surprisingly functional - my one came properly connected unlike the EEVBlog one and the resistance tallied up nicely with the nobs.

The resistor box

The construction is surprisingly simple and quite clever. The PCB is pretty efficient, needing only 5 resistors for each selector switch.

The resistor box PCB

This is pretty ingenious - I’m sure it’s a well known technique, but I think it’s pretty clever and it’s new to me. Taking the 100 ohm ring as an example we have 4 x 100 ohm resistors. As the knob rotates we switch these in series into the circuit. Once we reach 400 ohms the next click of the knob switches in a 500 ohm resistor and then subsequent clicks switch in the 100 ohm resistors in series with the 500 ohms.

Clever resistor switching

The problem is, as you can see from the image of the PCB, we’re just scraping the contact over the bare copper, we’re slowly scratching away the surface.

Ideally we need a hard wearing coating over our soft copper. Let’s try a bit of nickel plating!

In theory this is pretty straightforward, you just need some nickel electrodes, some strong white vinegar (5% acidity) and some electricity.

What you should end up with is some really nice greenish/blue liquid. My initial attempt produced something that looks like it belongs in the toilet.

Some interesting liquid…

My error? What I thought was pure nickel, was actually steel with a very thin nickel coating.

Not nickel…

But, after a bit more careful shopping I did end up with something that looked quite nice.

Some nice liquid

In the shallow dish the color looks slightly washed out, but if you look at it side on it’s actually quite nice color.

Don’t drink this…

A quick test with a coin produced some pretty promising results.

Oooh… shiny!

And after a bit of work to jumper over the resistors on the PCB I set to work trying to electroplate the copper.

The results were not ideal…

Plating failed

There were a number of issues:

  • Despite my testing, some of my jumpers weren’t soldered correctly.
  • Using a very shallow dish meant that the plating solution didn’t reach all the areas with equal concentration.
  • I also got a bit impatient and used too much voltage - which causes a lot of hydrogen bubbles.
  • Some of the copper was not very clean and was badly oxidised leading to poor coating.
  • I tried to clean the copper by doing some reverse electroplating - this contaminated my liquid with copper, lead and various other metals.

Fortunately, this wasn’t the end of the world - I’d already recreated the PCBs and ordered some nice versions from PCBWay.

Nice PCB

This PCB is a drop in replacement for the existing one, but it still suffers from the same problem of the contacts scraping on the surface. I do have several spares now as I ordered 5 of them. But I thought it would be interesting to try coasting these PCBs.

Coated PCBs - left - plated, right - original

This worked considerably better - I used a much lower voltage. I think my liquid is contaminated, but I did get quite a good coating.

Did it actually make the PCBs tougher? I think it might have done - I did a very unscientific test and tried to scratch the surface and I think the nickel coated version was harder to scratch.

Left - plated, right - original

It felt harder to scratch the coated version and it certainly looks like the uncoated version has deeper scratches.

More experiments are required - it’s certainly interesting.

The bits and bobs:


Related Posts

Scripting KiCad to make coils - I've been diving deep into the world of PCB (Printed Circuit Board) coils, inspired by Carl Bugeja's incredible PCB motors! After deciding to set up an automated process for creating the coils rather than manually drawing them (can you imagine?), I found our main constraints became track width and spacing, and the number of layers we could use. During the process of creating spirals for our coils, I encountered some interesting problems - spirals are easy, but what about arbitrarily shaped coils? My attempts ultimately lead me to develop more efficient algorithms and KiCad plugins to generate these special coils. A rewarding challenge of math, programming, and electronics! My code has been published on GitHub, and I’m eager to see how others might make use of it!
The PCBs are in production - what have I messed up? - After some stress and trepidation, I finally took the plunge and sent my PCB design off for manufacturing. My design centers around building a large seven-segment clock with LED filaments. Jumping hurdles such as voltages, pin usage, and limiting the load on my power supply, I've settled on the ESP32 as the system's heart and come up with a final circuit design. While doing this, I've quickly realized I could improve my layout and fixed a small mistake. Also, I've prepared for either types of LED filaments - the high-voltage ones or the larger, 3v ones. However, I did bungle up a couple of things on the enable line of the shift registers and board layout. But hey, this is a learning curve, right? Can't wait to get the boards and see what other exciting errors surface!
Printing PCBs At Home! - Got my hands on a Voltera machine for at-home PCB prototyping - it's a game-changer! Using conductive silver ink, it prints traces and pads, but it's quite finicky, much like 3D printing. It has limitations, such as trace widths, pin pitch for SMT components, and the high cost (over $5000). Plus, this tech requires a delicate touch due to the fragile ink bonding. Despite the machine's impressive capabilities, my partnership with PCBWay is still going strong, as this isn't a one-size-fits-all solution. Nonetheless, the ability to whip up a PCB in just a couple of hours is seriously impressive.
No Power? No Problem! A Wireless Pi Doom Machine - In my latest wireless charging experiments, I got my hands on a set of wireless charging PCBs and dove into testing different voltage inputs and their efficiency levels. It was interesting to realise that the 5V input managed to provide a decent efficiency of 73%, while 12V input struggled and heated the receiver board excessively. With the perks and limits of this setup explored, I took a whirl at creating a wireless Pi Doom machine. It worked like a charm! However, I quickly noticed the need to split charging and boost board into two different modules - a project to look forward to. Half the fun is getting there! Check out the video [here]( for more detail on the project.
Picking up Free Lithium Cells Off the Street and Making them Safe for Use - This blog post reveals how you can salvage lithium cells from the many discarded, disposable vape devices that get littered in our towns and cities. With a pair of pliers and some bravery, I managed to rescue some decent batteries, which still had a good amount of power in them. However, with no in-built protection in these cells, I also demonstrated the importance of adding a battery protection board to ensure they are safe for use in various projects. Conclusively, through rummaging in the trash, I not only acquired useful components for my projects but also took a step towards making the planet a cleaner place.

Related Videos

Nickel Coating PCBs At Home - In this experiment-filled video, I explore the inner workings of a resistor box I spotted on the EEVBlog channel. With its ability to adjust in increments down to 0.1 ohms, I was fascinated, but also noticed the binding posts could do with an upgrade. Upon inspection, I was intrigued by the simple yet clever construction and the possibility of enhancing the durability of the copper with some nickel plating. Navigating through the potential challenge of the resistors on the PCB, I embark on the journey of creating a homemade nickel plating solution. A few hiccups, adjustments, and an hour later, we end up with a liquid emerald green solution, ready for some plating experiments.
Printing PCBs At Home! - In today's captivating episode, I take a shot at home printed PCBs rather than buying from our faithful PCBWay, leading to some riveting discoveries. Using a stunning Voltera machine, my single-sided print echoed a glistening marshmallow-like texture that was cured just lovely in the oven. Encountering limitations, such as weak conductive ink bonds and layout tricks, brought on new challenges but also widened my horizon for potential improvements, such as considering a direct USB connection experiment. Despite issues, our creation came to life through intriguing stages of soldering, placement, and reflow, resulting in a successful quick prototype with operational LEDs and programmable features! Our exploration does remind me of the value of PCBWay though so have no fear, our Atomic 14-PCBWay partnership continues on. Keep watching for more such adventures!
Sneak Preview of work in progress. - Dive into the fascinating world of PCB coils with this informative video, showcasing innovative ways to create and experiment with them. Get ready to be inspired by @CarlBugeja's groundbreaking work!
How Good Are My USB Cables? - In this video, I engage in a deeper exploration of USB testing, encountering a range of trials and tribulations along the way. First up, I attempt to test a couple of USB cables and discuss their data lines' peculiar situatedness. Then, I delve into the assembly of the PCB boards, sourced from PCBWay, which surely turned into a learning voyage than an easy sail. The first version faced challenges of misordered large-frame stencil, unseen connection problems, and even DRC errors in the submission process. Not dwell on that, I redesign and bring to table Version 2, complete with USB connectors with broken-out pins and designed for visual inspection ease. Although this version demonstrated success, soldering difficulties and bad connections persisted. Considering all the hurdles, I decide to let PCBWay handle the assembly for the next version. For future strategies, adding test points and eliminating the lithium-ion charging circuit seemed more practically viable. Peeping into version 3, testing points for all USB cable pins have been added and even an option to break out actual USB connections, all towards ensuring an improved error checking and usefulness of the assembly.
Lots of Stuff - And a NEW PCB! It's a rare mailbag video. - In today's episode, I'm unboxing some goodies from PCB way - my super tiny esp32 breakout boards, which I'm planning to use to recreate a mini TV complete with speakers and a display. Also received some convenient adapter boards for easier testing. Excited to explore a new Arduino Nano esp32 based on a different, tinier module, and contrasting it with other products like the Tiny Pico. Also up for testing is a new mini wear electronic load compared to my old one, and an ATX power adapter for more USB ports. I'll be testing power banks, playing with inexpensive yellow displays and nunchucks for fun gaming projects, and testing out an RGB bead curtain with hackable possibilities. Also, under my ongoing experiments is a Raspberry Pi zero, turning into a 'Doom' playing device with added sound and game controllers. Finally, an air quality measuring device for detecting air particles, CO2 levels, humidity, temperature and other parameters is up for exploration as well. A whole array of fun projects queued up, so stay tuned!
HELP SUPPORT MY WORK: If you're feeling flush then please stop by Patreon Or you can make a one off donation via ko-fi
Want to keep up to date with the latest posts and videos? Subscribe to the newsletter
Blog Logo

Chris Greening


> Image


A collection of slightly mad projects, instructive/educational videos, and generally interesting stuff. Building projects around the Arduino and ESP32 platforms - we'll be exploring AI, Computer Vision, Audio, 3D Printing - it may get a bit eclectic...

View All Posts