You can easily build some of these circuits with very low investment. The ICs (555; 4017; ...) for circuits like the "LED sequencers" are very cheap (less than $1/1€ each). With ICs in DIP packages [0], the circuits can be built on breadboards [1] since the pins can be inserted directly into the holes of the breadboards. If you are new to this then you can find an overview of electronic symbols in Wikipedia [2] for example - this is helpful because it gives you names and terms to search for.

Having even a cheap multimeter to measure voltages, resistances or the polarity of diodes is better than nothing btw (but better don't use these to measure line/mains power - even if they claim to be able to do that).

Have fun!

[0] https://en.wikipedia.org/wiki/Dual_in-line_package

[1] https://en.wikipedia.org/wiki/Breadboard

[2] https://en.wikipedia.org/wiki/Electronic_symbol

According to https://yaqwsx.github.io/jlcparts/ the NE555DR costs 11.98¢ but of course not in a DIP. That's about as much as four Padauk microcontrollers these days—if you can find those in stock somewhere. JLCPCB doesn't include the CD4017 in their "basic parts" list; Digi-Key has them for 52¢ but doesn't have a DIP version in stock, just an SOIC.

The other night I took apart my cheap multimeter which claims "1000 V" and found no creepage clearance between the traces on the board. So far I haven't died measuring mains power with it but I don't think I'll do that anymore...

555 timer is a sub-10-cent part in quantity. Digi-key even has the NE555P in stock for 40 cents onesies and 11 cents in 2500 unit orders. And there's a parts shortage on, if you haven't looked lately.

Yeah, don't use cheap tools when your life is on the line.

Yeah, it's 8.87¢ in quantity 50. That's still the cost of two Padauk microcontrollers.

so what's your point? people should be buying a reel of one time programmable microcontrollers that you'll have to program in an esoteric language in a proprietary toolchain and a programmer that costs more than 8 cents? Or put together one of those open hardware programmers themselves?

I mean the padauk stuff is not really a very beginner friendly environment, and it's not as cheap to get going once you consider the accessories needed. just buying and re-using an arduino or a knockoff for a couple dollars would probably be better if you wanted to make the case that a microcontroller is a better place to start.

I had several points:

1. For jellybean ICs "less than [US]$1" understates the case by about an order of magnitude; it's less than [US]$⅒.

2. Other ICs mentioned like the CD4017 have ceased to be jellybean parts and have become esoteric specialty parts, but they're still less than US$1, if you can find them.

3. The reason for this is that, as microcontrollers have gotten cheaper and more capable, the range of circuits for which they are a good fit has grown enormously, and in particular covers just about every circuit where you'd use a CD4017. And once you have a microcontroller in your circuit you probably don't need a 4017 or a 555 because you can usually replace them with 1–5 lines of code.

4. Probing line power with a questionable-quality multimeter really is dangerous.

Does that clarify?

I agree that Arduino is a much more beginner-friendly environment, even more so than quasi-analog DIPs in a breadboard, and also that the programmer hardware for the Padauk μCs is a significant obstacle.

Sorry, for some reason I saw $11, not 11 cents and thought you were looking at a broker site at a very particular part.

The biggest reason I wouldn't use Padauk microcontrollers is that they're not available in north american distribution.

I personally really don't get the 555 timer love - almost anything people would do with one for a small design with no firmware, I would use an lm339 type quad comparator. They are great for detecting the presence/absence of pulses though.

Wow!! I love this so much!

I don't even like building this kind of pure analog stuff, but this retro site is just such a wonderful thing. Just like the days when tech was still exciting, despite being so much more primitive.

You’ll love this one too. If you look at in on your phone, make sure to see the wide view with all the buttons.

https://www.newmodellersshop.co.uk/

I’ve had the tab open for years, can’t bear to close it. I should get a big printout and hang it up.

love that wonton soup recipe

Would look smashing in Papyrus.

OK, I only said that because it displays in Comic Sans on my Windows desktop (Chrome, Opera, Firefox, Edge), but now I see it looks fine in Times on iOS (Safari, Opera).