KiCad is a great schematic and PCB design tool. It is easy to learn and fun to use, above all it is free. In this blog post we are going to design a simple circuit based on the 555-timer chip in astable mode.
After the dry film is applied to the copper layer, it can be etched. There is an option to use ferric chloride (FeCl3), but it can not be reutilised and needs to be disposed. An alternative is to work with a mixture of hydrochloric acid (HCl) and hydrogen peroxide (H2O2), which can be regenerated with air and reused for the etching process.
If you can not afford a real NIXIE tube watch, there is an alternative. It is this 4-digit 7-segment LED watch kit. It costs less than 10 euros and you can find it on most Chnese resellers websites. It comes as a kit and you will need to do a bit of soldering and assembling.
The most important advantages of ABS are impact resistance and toughness. Lego is made from ABS. It will also not deform in hot water, compared to PLA. On the downside ABS is hard to print. You need very hot printbed (around 110 degrees Celsius) and Kapton tape, so the first layer will stick properly. ABS can also warp and curl. There are also other issues in the Marlin firmware that need some attention.