Tag Archives: binary clock

Binary Clock, Part 2

The long awaited part 2 of this blog post has finally arrived! But first, a video, in case the whole “reading” thing isn’t your bag…

Though I’ve been tinkering on this project for the past two years, I decided to write it up to coincide with the outrageous arrest of 14 year old tinkerer Ahmed Mohamed who was hand cuffed because his teacher thought his electronic clock project looked like a bomb. This binary clock project of mine ended up being a personal electronic circuit design introduction course. You can download all the relevant files here if you want to make your own.
I forgot what the original inspiration was but what I’m ending up with is a working binary clock on a custom printed circuit board. Ultimately, this project will involve fiber optics inside polished cement for a unique time piece but we’re not there yet… Here’s what I learned so far:

Bit shifters

A binary clock needs 20 individual blinky things and the arduino has less than that, so I needed to figure out a way to create more individually addressable outputs. The solution I found is a the 74HC595N chip that can turn two inputs into 8. In fact, you can wire them in series and they can provide you with any number of outputs in multiples of 8. I decided to use one to drive the hours display, one for the minutes, and one for the seconds.

There are tons of tutorials for them so it was fairly straight forward to get it working.

Keeping time

While you can make a timer with just an arduino, it is not very accurate and it has no way to keep the clock going if you unplug the power. I used a rtc1307 chip which is designed for just this purpose. It keeps time accurately and uses a small battery to continue keeping time when the power is disconnected.

Again, there is an arduino library available and a good amount of tutorials out there so it wasn’t too hard to test it and incorporate it in the build.

Removing the arduino

Eventually, since I wanted to end up with a single circuit board, I didn’t want to have to plug anyting into an arduino. Once again, the internet is a wonderful resource which allowed me to figure out how put only the arduino components I needed onto a bread board. I can upload the code onto the chip by putting it on an arduino, and then pull it off of there to mount it directly onto the breadboard.

Code

The clock can be set to one of 4 modes: display time, set hours, set minutes or set seconds. There are two buttons. One button toggles between all the different modes, while the other increments the count of the hours, minutes, and seconds when they are in their respective mode.

Schematic and board

Once the breadboard was working, I set out to sketch the circuit in Fritzing. While it’s not quite as intimidating as EAGLE cad, I ended up using the latter after running into some limitations with the former (I don’t remember what they were). There was a lot for me to learn there but, in the end, it’s conceptually pretty simple: all the pieces have to be connected together correctly. It’s just another way to represent the circuit. Once that was done, I started with the board. I laid out all the components and let the software automatically figure out how to create the correct traces.
One cool thing is that if you choose the correct electronic components in the software, all the size and shapes are properly represented when you are designing the board. It’s a huge pain in the ass to sort through all the libraries of components, though, specially when you don’t know what all the specs mean.

The eagle cad files are included in the download file at the top of this page.

Manufacturing the board

Super simple: just go online and find a service that will manufacture them. For this project, I used oshpark.com and dirtypcbs.com, which allow you to upload your designs right out of EAGLE cad. After a few weeks, you get your board in the mail, ready for you to solder the components on. I order my components from mouser.com, which allows you to save a collection of various components into a project specific list. Again, finding the right components amongst the tens of thousands they have available is really time consuming and annoying. But now, I have my parts list so I never have to go through that again if I want to solder up new versions of the board. The list of parts in included in the download file at the top of this page.

The ugly truth

If you were paying attention, you no doubt noticed in the preceding paragraph that I used two board manufacturers. That is because the first board layouts I had printed actually had shorts. I suppose it’s probably not that uncommon, but it’s really frustrating to upload your designs, order the boards, wait for them to be delivered, spend all this time soldering the board to find out it doesn’t work, and then it can be challenging to figure out where the wires are getting crossed. In the end, I spent about $150 on boards and parts that ended up not working. I guess that’s the cost of learning… My first two board designs were ordered through Oshpark, and the minimum order was 3, for about $50. The third order was done on dirtypcbs and was $25 for 10 boards. They feel cheaper and took forever to get delivered but you sure can’t beat the price.

Binary Clock, Part 1



Binary clocks are a family of ubiquitous geek toys which display each digit of the time using binary notation. If you do a search for "binary clock" in Google, you will see a nearly infinite number of implementations. The reason I like the whole genre is that a binary clock is an electronic system that claims to exist for the purpose of conveying information when in fact it's all about finding an obtuse excuse to make something blink. The delight of it is that it's completely impractical to read but the geeks don't care: the coolness of the blinky lights joyfully trumps any need to be practical.

Speaking of geeks, I've been wanting to look into this whole Angular.js framework thingy all those overly bearded tech-hipsters are talking about (when they are not crafting their own cheese or riding fixed wheeled bikes), and so I'm using this blog post as an excuse to program simple apps that illustrate the process I am talking about using Angular.

Displaying numbers in binary

You can see below how to calculate the value a binary number. It's pretty straight forward: a particular place can only be 0 or 1 and once you increment above that, you loop back to 0, add one onto the digit to the left, and if THAT one is already 1, it also loops back to 0 and the behavior ripples leftward.

binary number {{get8()}} {{get4()}} {{get2()}} {{get1()}}
x x x x
place 8 4 2 1
= = = =
total {{8*get8()}} + {{4*get4()}} + {{2*get2()}} + {{1*get1()}} = {{count}}

Notice that the highest number we can represent a maximum of 16 values with 4 b(inary dig)its. 8 bits can represent 256, 10 bits, 1024, and so on...

Displaying the time in binary

The following table shows how to display the time in binary format, with each digit represented by a four bit binary representation arranged in a column. The current time is {{getTheTime() | date:'mediumTime'}}, which you can see displayed in 24 hour format in the bottom row.

{{d}}

From math to art

Not comfortable with numbers? Replace the 1's with teale and the 0's with burn sienna, on a background of deep emerald. Bam! Suddenly, you've become an artist, conjuring a playful visual dance of colors on an abstract rhythmic canvas. You're a fucking genius!

{{d}}

(Note that since the highest number for the hours is 23, the first column never has to go above 2 and we really only need the bottom two places to represent that number. Similarly, the value of minutes and seconds only goes to 59 so the third and fifth columns only to represent the value 5, which can be done with only 3 bits.)

What's next?

Stay tuned... Part 2 describes how to build your very own binary clock, using LED's, chips, electricity, obsession, and patience.