This is powered over a mini USB connection. It does not interface with a computer, it only leeches power from the USB port.
This is a great project for beginners, or anyone looking for a binary clock to build, or an easy binary clock to mod.
This project took me about an hour to complete.
Step 1: LED Installation
The footprint of the LED is silk screened on the board. Not all of the LEDs are arranged with the same polarity. Check every LED for the proper alignment.
This is the focal point of the project, so we want it to look nice. Once the LED is placed in the board, I recommend a small piece of masking tape to hold it flat on the board while it is being soldered in place. If nothing is holding LEDs in place, they may solder in place at unwanted angles.
Once they are soldered in place, the leads can be clipped off.
Placing the LEDs in the four corners first, will permit an even work environment, and make placing LEDs straight and flush against the board, easier.
Step 2: Resistors
The resistors limit the current any LED's can draw to about 20mA. Without them, the controller would be stressed and the LED's would wear out too quick.
Step 3: Capacitors & Crystal
None have polarity.
The crystal provides a stable oscillation source. It "ticks" several millions times a second, which the micro-controller counts and translates into seconds, minutes and hours. The capacitors keep the crystal stable and insure they have enough voltage to get going.
Step 4: USB
This can be added to the project with as few as four solder points.
While connecting all the points are going to secure the port better, and keep it safer in the long run...the pins are very close and can be difficult to keep solder separated. Be sure these solder points do not touch. Connecting these points to each other can damage computers. Those pins correspond to power, ground, and data transfers.
If you need to see that is going on within this port, here is a third party pin-out.
The important connection to make is the bottom left, and right, with the board orientated as shown below. In addition to those points, the two mounting points that hold it to the board need completed. Below, I have the far left point completed, this is the positive 5v connection. In addition to this, the far right pin needs soldered in place, to ground the circuit.
Step 5: Attiny45 Microcontroller
The leads on the socket are short. Placing a piece of take to hold it down like the LEDs, while soldering, is advisable.
When putting the controller in to the socket, be sure to align all of the legs, and apply pressure evenly. The legs of the controller are easy to bend.
The controller works as the "brain" of the project.
Step 6: Power, Case, Read & Set
To set the clock touch the sensor. After 5 seconds the clock will begin to advance time. After the minute ones are cycled through, the minutes tens are cycled and finally the hours. When you remove your finger the advance will stop and the clock will hold the time. Set the hour first, then the minute tens and last the minute ones.