How the Clock Works — from the Outside.

Our clock has only three interface elements; a big blue display (the time), a smaller yellow display (the alarm time) and a knob. Pressing the knob turns the alarm (and the yellow display) on and off. No yellow numbers, no alarm. Yellow numbers? That’s what time the alarm will go off. It’s that simple.

You change the alarm time by turning the knob. It moves in 15-minute increments, so in a couple of spins (forwards or backwards) you can move through a whole day. I’ve always thought that the little AM/PM light was hard to notice, so we’ve done away with it here. You set the alarm in 24-hour time. which makes it really hard to get it wrong; 7:00 AM reads as “7:00″ while 7:00 PM reads as “19:00.”

That just leaves the noisemaker. Rather than leave it up to the a radio station, which has too many parameters to set (volume and tuning) or may have unreliable programming, I decided to include my own noisemaker. Sure, we could have interfaced to an iPod, but adding another device undermines our assurance that the alarm will go off as planned. Instead, I’ve chosen to play sound files off a micro-SD card. This gives us lots of other capabilities as well, like making the clock chime on the hour, speak the time, or play different alarm tones at different times. Since the reader accommodates a 2Gb card, you can design your own audio “skin” if you like.

Last, but not least, we solved the power problem. With the old mechanical clocks, you lost exactly as much time as the power was out. With digital clocks, even a brief power interruption restarts the clock at 12:00.  Some clocks have a back-up battery in case the power fails, but most do not. The ones that do, require you to replace the battery periodically (which no one ever seems to do).

This clock keeps the correct time even when you pull the plug. For how long? At least a few days and maybe a couple of weeks (there are a lot of factors involved). The displays turn off and the alarm can’t sound when the power is off, but when power is restored, the time is still accurate.

How the Clock Works — from the Inside.

The guts of this machine contains a hard-working and very inexpensive 8-bit PIC microcontroller. (It’s the long rectangular black thing in the picture.) There is also some audio circuitry to play sound files off a micro-SD, an amplifier to drive a speaker, some LED displays, and a power supply to make it all work.

The Logic Board

The PIC microcontroller does all of the heavy lifting, keeping track of the time, managing the two displays, controlling the audio chip, and handling user interaction.

One more component worth mentioning is the carbon aerogel supercapacitor. (It’s the big round thing on the logic board.) This little guy stores up electricity when we’re plugged in. When we’re not, the microcontroller senses the power failure, shuts down everything non-essential and hunkers down for a long winter. It draws just enough power from the ultracapacitor to stay alive and keep track of the time. Supercapacitors are cool because, unlike batteries, they don’t get tired of charging/discharging so they don’t need to be replaced periodically.

Mechanically

I decided to build this clock into a CD storage container. It was about the right size, inexpensive, and I liked the color. In order to give myself a little more flexibility, I put all of the electronics on two boards instead of just one. There is a display board, which holds the digital displays and the knob, and a logic board which holds the microcontroller, audio electronics, and power supply. A 16-pin connector mates the two boards together.

The Display Board

The size of the display board, which is the larger of the two, is primarily determined by the size and placement of the LED displays. By putting the rest of the electronics on another board that mates behind it, I gave myself the option of fitting the whole thing into a smaller box than I could have if it were all on one board (in case I change my mind later).

In our next installment, we’ll talk more about the details of the design and how engineers design something like this.

Related posts:

1. Building the Perfect Alarm Clock in (1200 Easy Steps)

You would think that a device so critical to modern life would be designed better, but in spite of the fact that there are thousands of models to choose from, they pretty much all suck. How often have you gone to bed the night before a critical meeting and been unable to fall asleep because you had no confidence that the alarm was set correctly? My own alarm clock requires at least a dozen cognitive steps to set the alarm with any confidence.

How it should work

You should be able to set your alarm clock in a few seconds. You should be able to tell from across the room if the alarm is set, and for what time. You should be able to set it in the dark, without your glasses. You should never be lying in bed wondering if you accidentally forgot to push some button or bumped the volume control and are going to get up late and look stupid.

So, forty years after the digital watch was rolled out at CES, I decided to design and built the perfect digital alarm clock. Even with all of the advances we’ve made since the 1960s, this has turned out to be a really interesting challenge. It involves assembly language programming, custom fabrication, parts suppliers from all across Asia, and an enterprising low-volume circuit board manufacturer based in Bulgaria. Why all the complexity? Because of the simplicity.

Simple = Complex

Let’s assume you want to fly to Los Angeles. (Don’t take it personally, it’s just an example.) Think about the steps you have to go through to make that happen.

• Determine when you want to go and when you want to return
• Go on various websites to find the right combination of itinerary, cost and airline
• Identify and use the correct payment method
• Manage your seat assignments
• Create appropriate reminders to ensure you arrive at the correct airport at the correct time
• Arrange for transportation to and from the airport

And this doesn’t even include packing luggage and all the personal aspects. This is just getting there and back. Now imagine you wanted to make this completely simple for yourself. What would you do? You’d hire an assistant and say “Steve, book me a flight to Los Angeles.” Very simple for you, but it requires that you interface with a highly complex and sophisticated machine — Steve.

The easier it is for the user, the harder it is for the designer. This is something I’d always more or less understood, but this project made that completely clear.

In the next posting, I’ll describe the clock itself: how the user experiences it, and the insane complexity behind that apparent simplicity.

(Read Part 2 of this article here.)

Related posts:

1. Building the Perfect Alarm Clock (Part 2)

QR code in the Wild

That funny looking symbol on my new business card is a QR code. Lately these little beasties have been cropping up on everything from T-shirts to magazine ads.

The QR (Quick Response) code is a two-dimensional bar code that can store contact info, URLs, even paragraphs of text. Although they were invented clear back in 1994, they were relegated to industrial applications until a new generation of consumer electronics made them practical for just about everything.

Now that phones like the Android and iPhone have easy to use software for decoding them, QR codes are spawning a new generation of applications called “hardlinking” or “physical world hyperlinking” that make it easy for consumers to capture data from products, magazines, billboards and even each other’s phones.

You can get your own QR codes to start pasting on stuff at the link below.

Related:

• Make your own QR Code courtesy of ZXing project

• Google image search of social QR code applications

• Silicon Alley Insider, “Mobile Barcodes: Big In France!”

Related posts:

1. Sprint Rolls out Flawed Android Strategy at Developer Conference

"Braindoggle"

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Nixie tubes

Back in 1954, before we had LED’s and digital readouts, Nixie Tubes were the only way to display digital data. Today, these delicate glass tubes are very rare.

I’ve been buying them from decommissioned factories in Russia and designing them into retro electronic devices like clocks and other art pieces.

Nixies fell out of favor as soon as other technologies replaced them because the fragile glass tubes are sensitive to shock and vibration and they require 180 volts to operate.

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