Poor quality eBay/Amazon/AliExpress alarm clock teardown

[@kevtris]

wonder what the crystal pins look like on a scope? maybe the cpu has some kind of RC oscillator and clock switchover in the event the crystal fails. and that crystal isn't even oscillating.

[@pdrg]

Wow I thought we'd managed to get over "keeping time" as a fundamental design pattern with 70's digital watches!

[@pileofstuff]

"As the batteries age, it's just going to speed up" - now there's a metaphor for our perception of time passing.

[@UberAlphaSirus]

You sure your not in a gravity well?

[@nickjones886]

How on earth can somebody get such a easy concept so wrong...

[@MrBobWareham]

It's China

[@petercutting6126]

I have one of these, it works perfectly. Setup take a few minutes, this is what most trouble with. The battery has been OK for over 9 months !

[@anameisrequired3729]

I suspect the sensor setting used to use an LDR or phototransistor, and somebody didn't copy it correctly. More light -> more current through "D1", less base current for Q2.

[@AintBigAintClever]

Ah, that would make sense if D1 was a (working) photodiode or LED. I've just looked at the PCB photo and my schematic has the LED the wrong way round, the flat edge (cathode) is actually going to the base of the transistor. I'll update the schematics saved on Facebook.

[@therealjammit]

Really? It's sensitive to voltage changes? I'd be curious to try and replace the crystal, just for kicks.

[@williefleete]

Must be using the crystal as a suggestion

[@magnets1000]

There is so much stuff like this on amazon/ali, where they go to a lot of effort to make a product then cut a corner on an essential part that makes the product e-waste. Why even bother

[@Pithead]

The chip's melted and turned into a round blob. I was looking up the history of quarts oscillators again on Wikipedia just yesterday - George Washington Pierce (Pierce oscillator). From Wikipedia 'By 1910 his first textbook Principles of Wireless Telegraphy was published. It is in this text, and others by John Ambrose Fleming, that the term modulation is first used to describe imprinting an audio wave onto a high-frequency carrier wave by variation of amplitude of the carrier'. Also - Walter Guyton Cady - 'was a pioneer in piezoelectricity, and in 1921 developed the first quartz crystal oscillator'.

[@pmsrodrigues]

Bought a store branded version of this at a local Swedish store- Jula -, and has been keeping the time right for months. The viewing angle of the screen with the back-light on, on the other hand, is atrocious. Next to unusable.

[@danielhorne6042]

should of raised the voltage to 12v to let the magic smoke out

[@stevecoatesdotnet]

You'd think a clock would be easy these days. I'll stick to my Casio wrist watch and my 40 year old Sony mains powered clock.

[@robbieaussievic]

...... Well done Mate, H.G. Wells could use it to meet the Morlocks.

[@diamondstar2897]

Not every clock looks like that bad. Here i have this which circuit is not same to you it has two circuit. 1 is on the top, and another is on back. But the body design is same to you