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Binary/POV custom wristwatchAll > Tech > Inventions > Binary/POV custom wristwatch by natetrue
Recently my good friend Andru Edwards and I got into a heated discussion about watches. My old Fossil Abacus PalmOS watch was getting pretty worn, and I was shopping around for new watches. Having seen a cool video-playing watch over at Gear Live, I was thinking I might upgrade to one of those, purely for geek-bling factor.
Andru, being more grounded than I am as far as fashion is concerned, suggested that the video playing watches I was looking at (I was searching DealExtreme for MP4 Watch) were all profoundly lame. So he told me to go look at the TokyoFlash watches which tell time using discrete LEDs rather than using LCDs or large pixel counts.
Of course, the TokyoFlash watches look amazing. But I wasn't planning to spend $180 on one. I mean, even the video watches maxed out at like $60.
So what does a maker do when he wants something but doesn't want to buy it? He makes a knock-off! I mean, it's much more respectable than that, because of how much work goes into it.
I decided to go with a binary representation, since it would require the fewest LEDs to represent the most information.
Want to buy one instead of making it, or buy all the parts from one place as a kit? Check out the Buy page. Got all the parts already or need a parts list? Skip to the Assembly section.
Here's how I made it:
It also used a ceramic resonator as its timebase, as I didn't have the necessary 32 KHz crystal nor the 33pF capacitors to have the accurate crystal timer.
That was just a detail, though. With the prototype I could develop the timekeeping logic and the display details.
I figured the watch should be enclosed somehow, rather than just being a bare board. So I trolled my local fabric store for some material. My eyes fell on this faux-leather brown vinyl with a nice soft cloth backing. It was fairly expensive but I did not need much of it.
I decided to use push snaps for now but I think a buckle with holes like a normal watch would be better for adjustability.
The concept of a POV display is very simple - using a single row of 5 LEDs, the PIC displays each column of the display in turn. When the watch is swiped through the air, each column is spatially separated from the last, allowing a "larger" display area to show with only 5 LEDs.
Ready to make your own? Great! Here's what you need. All of these elements are included in the POV watch kit which you may have noticed you can buy from me.
Got all that? Let's get started!
You may wish to elevate the LEDs if you're making an enclosure, so they stick up past the buttons and the IC socket. Keep your final container in mind. If you're building from a full kit, you'll want to have the LEDs elevated at least 2 millimeters above where they'd normally sit, and you will want to secure them somehow so they don't bend side to side.
Remember the LEDs are polarized so make sure the cathode leads (the shorter ones) are toward the buttons on the board. Solder the leads to the back side and clip them appropriately.
The MAX1555 is VERY tricky to solder. Make sure you have a magnifying glass on hand to observe your work. As shown, one of the pins is not needed, and two of the pins are soldered together to one of the button terminals (this is a ground connection). Make sure you don't bridge any of the other pins with solder!
Since soldering the 1555 is so difficult and the thing is so small, kits ordered from me will come with this part already soldered in.
Using your watch
What good is a watch if you can't use it? When the watch is first powered on it will think it's 6:57 PM, since being 12:00 AM results in no lights of the display being on and you'll think it's broken. The display automatically turns off after 10 seconds when in clock or POV mode, so press any button to turn it on.
Here's how to tell time in binary mode:
In the Hours area (the top row, right 4 LEDs), only the LED with the value 4 is on. So the hour is 4 PM.
In the Tens of Minutes area (middle row) the LED with the value 4 is on. So the tens of minutes is 4 also.
In the Ones of Minutes, we have the LED with the value 1. So the ones of minutes is 1.
That makes it 4:41 PM.
The watch has several different modes. You can switch modes by holding the center button until the mode changes, then releasing. You can always return to Clock mode by pressing and holding the center button until the watch returns to Clock mode. All modes except Flashlight mode will turn the watch off after 10 seconds. To wake the watch, hit any button.
Do not look directly into the LEDs during Flashlight mode, as they will leave a lasting image on your eye that may interfere with vision for several minutes.
The last two modes aren't very useful and are not interactive in any way.
In Binary Clock mode, you can hold the left and middle buttons together to reduce the brightness, and the right and middle buttons together to increase it.
Press the left and right buttons at the same time to shortcut to Flashlight mode.
In POV clock mode, you swipe your wrist through the air (bringing the watch downward) to write the time in the air.
When in one of the setting modes, pressing left or right will decrease or increase the current number, respectively. To exit setting mode, press and hold the center button until it returns to clock mode. To go to the next setting mode, press and hold the center button until the mode changes, then release.
I hope you enjoyed reading about my watch as much as I enjoyed making it.
Be sure to check out my other stuff!
(more recent creations)
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