Raw Thrills Pac Man LED Desk Clock now 50% off...$39.99!

I know Amazon's reviews can be somewhat biased, but how does a clock that can't tell time get 4.5/5 stars?

coolness factor? i doubt 80% of the people buying this garbage is doing it for a clock. they want to see pacman and the ghosts run back and forth like theres no tomorrow...

rather waste your $40, come up with another $210 and spend your $250 on this game frame: https://ledseq.com/product/game-frame/
 
Assuming it powers on to 12:00AM, could you plug this into a programable lamp timer and have it turn off at 11:59PM and back on at 12:00AM to reset it daily?
 
Despite the time keeping factor, the clock is always
a popular conversation piece on my desk from fellow
employees who pass by.

One of these days I plan to crack it open and see what
makes it "tick".

JD
 
Mine is still running strong after a year of use. However as others have said, it does loose time after awhile.
 
i purchased one too at $40, how the hell could you not?!

i could care less if it tells time, i just wanna see the pacman go wakka wakka across the screen!
 
I bought one and love it! Time keeping issues don't bother me, I just adjust it every couple of weeks. I do wish there was a Pac-man/Mrs. Pac-man toggle option though...
 
It would've been much cooler if it ran through all the intermissions with sound - that's one I would buy .
 
It would've been much cooler if it ran through all the intermissions with sound - that's one I would buy .

Yes! A different intermission at the top of each hour, with a unique intermission at noon...but no audio during nighttime.
 
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I never heard that, though they definitely should... they're probably doing something stupid, like:
Code:
while(1)
{
  update_gfx(); //usually takes around 50ms
  delay_950ms();
  seconds++;
}

Definitely not using an RTC... I've never seen an RTC that couldn't keep decently accurate time over just a few days.

DogP

You don't think it's just a cheap oscillator? I guess it would have to be pretty freaking crappy to lose minutes over a few days. I was in charge of the spacecraft clock on the NASA MESSENGER mission. We had this thing called the OCXO - oven controlled crystal oscillator. It was our "precise" oscillator and normally drove the clock. We also had backup ones that were "coarse" and those drifted a few secs over a few weeks time at the worst. The OCXO was amazing. It drifted a few billionths of a sec per day, if I remember right. It was primarily needed to label laser altimeter data taken of the Mercury surface. It was so precise, it could measure the relativistic time dilation caused be changes in velocity and gravity! It literally enabled us to see time slow down and speed up. That was pretty damn cool. The OCXO engineer & I accidentally discovered it had that capability. We thought that we were seeing some systematic error, and it turned out we were seeing relativity!
 
You don't think it's just a cheap oscillator? I guess it would have to be pretty freaking crappy to lose minutes over a few days. I was in charge of the spacecraft clock on the NASA MESSENGER mission. We had this thing called the OCXO - oven controlled crystal oscillator. It was our "precise" oscillator and normally drove the clock. We also had backup ones that were "coarse" and those drifted a few secs over a few weeks time at the worst. The OCXO was amazing. It drifted a few billionths of a sec per day, if I remember right. It was primarily needed to label laser altimeter data taken of the Mercury surface. It was so precise, it could measure the relativistic time dilation caused be changes in velocity and gravity! It literally enabled us to see time slow down and speed up. That was pretty damn cool. The OCXO engineer & I accidentally discovered it had that capability. We thought that we were seeing some systematic error, and it turned out we were seeing relativity!

Heh, yeah... I have a bit of experience with oscillators. :) I build and use lots of hardware with Rubidium and OCXO oscillators for very high time and frequency accuracy... as well as TCXOs and cheap/standard XOs. Oscillator specs are one of the first things I look at for most projects. If they used just about any crystal, I can't imagine that's the problem.

Generally, an RTC is driven by a 32.768KHz crystal, with somewhere around 20ppm (parts per million) accuracy. This clock has error that's WAY outside of that spec. And since it's parts per million, the frequency of the crystal doesn't matter (i.e. a 10MHz crystal off by 20ppm will keep the same time accuracy as a 32KHz off by 20ppm). The easier way to think about it is that it'll be off by at most 20 seconds over 1 million seconds (~11.5 days).

I guess it's possible that they went really cheap and rather than using a crystal, instead used an MCUs internal RC oscillator (that'd be a very amateur move for someone making something intended to keep time). Those are usually spec'd to around 1-5%, or sometimes the really low power ones, much worse. In that case, being off by even 1% would give HORRIBLE accuracy (up to 14 minutes per day). I can't say my clock was ever that bad. Like most oscillators, they're VERY sensitive to temperature, so they'd run quite differently depending on temperature.

Most plug-in clocks simply use the line frequency to keep time. Line frequency is kept to pretty good long-term specs, though that's why you can't usually use a US clock abroad, even if you have the voltage converter (the clock will expect 60Hz but only get 50Hz and run slow). Of course this clock uses a wall wart to supply DC power, so that's not possible.

DogP
 
Got mine now setup at my office.
Very cool (and bright).

Anyone open one up as yet and see what's inside? Any pics on the WEB?
Similar to the 3D projector ... would be nice to add more animations to this clock ... (come on DogP, I'm lookin' at you ...) LOL ;)
 
Anyone open one up as yet and see what's inside? Any pics on the WEB?
Similar to the 3D projector ... would be nice to add more animations to this clock ... (come on DogP, I'm lookin' at you ...) LOL ;)

beat dogp to it... see attached pix

led grid is 16x32 (512 pixels)

looks like the brain of the smaller pcb is controlled by an ATMEL MEGA328P

let's hack this fucker!
 

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...and it looks like a battery can be added for those interested.

:D

EDIT: And have you tried adding a speaker to see if there is some sound?
 
So, it's 2 boards and the display is separate from the the CPU. You couldn't ask for a better scenario.

One way would be to reprogram the existing chip.
The best way would be to design a new CPU board or a daughterboard for something like a Pi. Then you can add sound, ntp, etc.

I'm sure someone is going to hack it to a pi fairly quickly for the look at me factor, but a nice open source library and distro with an easy way to change animations would be the perfect goal.

You could easily hack this to tell time with animations, but also high scores or whatever you want out of a general purpose LED.
 
So, it's 2 boards and the display is separate from the the CPU. You couldn't ask for a better scenario.

One way would be to reprogram the existing chip.
The best way would be to design a new CPU board or a daughterboard for something like a Pi. Then you can add sound, ntp, etc.

I'm sure someone is going to hack it to a pi fairly quickly for the look at me factor, but a nice open source library and distro with an easy way to change animations would be the perfect goal.

You could easily hack this to tell time with animations, but also high scores or whatever you want out of a general purpose LED.

yup, we should totally hack this!

the 16x32 rgb led matrix panel is this $24.95 pcb: https://www.adafruit.com/products/420

To program the board, you'll need an FTDI cable or FTDI friend. Or you can program the ATMega328 chip using your Arduino board and move the chip to the RGB Matrix Backpack for testing.

Nootropic RGB matrix backpack kit ($19.95): https://www.adafruit.com/products/2657

The 6-pin programming header makes it easy to program the board using the Arduino IDE and a cable or adapter like an FTDI cable or FTDI friend

FTDI cable ($17.95): https://www.adafruit.com/products/70

FTDI friend ($14.75): https://www.adafruit.com/products/284

A small tactile button can be used as an input to your Arduino program. It is connected to Arduino pin 11. To use the button, the setup() function in your program should call pinMode(11, INPUT); digitalWrite(11, HIGH);. The button is read by calling digitalRead(11).

more explanations on in/out here: https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/new-wiring

entire project with arduino code: https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/
 

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