Another successful build!

[arclight]

In a word: w00t!

I didn't learn as much (i.e mess up) on this project as I did on some recent ones though I did manage to repeat my Trouble With Installing the Proper Capacitors issue. At least this time around I noticed it before I got to the testing stage and it wasn't as irritating to recover from. Lesson learned: never trust the pictures because the parts in the kit came from a different batch than the prototype. Remember, suppliers are legally required to change the color and shape of the components they ship once up-to-date assembly instructions are published.

There was a scare that I had a diode in backwards but it was just lighting. Also, when I was looking over the schematics after assembly, I worried that I had accidentally swapped one of the Schottky diodes for the 1N4001 in the 9V-to-5V regulator subsystem but a quick review of the parts list confirmed that the 1N4001 was replaced by a 1N5817 and all was well. At some point I will have to dig out my old copy of The Art of Electronics to sort out what the difference is. The book is a wonderful bench reference apparently, but a godawful textbook. I think I've kept it around since college either out of spite or as motivation to make good use of it.

Regardless, here's a picture of my clock in all its Soviet-era glowing aqua magnificence:

It's ... ALIVE! Now make it stop beeping.

RAA_ice_tube_small.jpg (78.61 KiB) Viewed 1192 times

Thanks again!

[len17]

This is explained on the Ice Tube "Design" page:

D1 is a protection diode, in the kit this is a schottky to avoid mixups but a 1N4001 is fine too.

So in this case the supplier is choosing the appearance of the components to help you.

As for the schottky diodes:

D2 is another diode, this one is used to prevent the tiny coin cell from back-powering the 7805 which has huge quiescent current (like 2mA). We use a schottkey so that the voltage drop is about 0.2V.

Also, schottky diodes are used in boost converters (like D3 here) because they can switch quickly. So no need to look it up, the Ice Tube is a textbook example of what schottky diodes are for.

[adafruit]

In a word: w00t!

I didn't learn as much (i.e mess up) on this project as I did on some recent ones though I did manage to repeat my Trouble With Installing the Proper Capacitors issue. At least this time around I noticed it before I got to the testing stage and it wasn't as irritating to recover from. Lesson learned: never trust the pictures because the parts in the kit came from a different batch than the prototype. Remember, suppliers are legally required to change the color and shape of the components they ship once up-to-date assembly instructions are published.

not sure what you mean by the parts have different colors and shapes than the instructions. the 20pF caps are orange ceramic discs, the 0.1uF are yellow ceramic multilayer. we havent changed that in any kit...?

[arclight]

No, this time my issue was with the electrolytic capacitors - the 6.3V 220uf cap (C4) was black and the 100V 22uF cap (C6) was the same blue as the 47uF caps. This is almost opposite of the assembly instructions but since the caps are generic components and the instructions have the right values, I don't see a way to make this clearer. The lesson is simple but one I'm frequently guilty of ignoring: always slow down and ID your components before soldering them in.

Again, you'd think I would have learned my lesson to be more attentive after diagnosing and repairing my SIM reader error, but at least this time I recognized the problem early and only had to desolder one component. FWIW, I had no problem IDing the ceramic caps or getting the oscillator caps in the right way. Also threading all those tube leads was tedious but went ok, though I should have looked at the design page when testing the pin-to-lead connections.

At some point I'll have to add the autodim feature but for right now I'm really happy with the way the project came out.