(As a quick recap, the other members of the Wise Clock family are, so far, the glass-domed Wise Clock and Wise Clock 2. They are "wise" because, along with the time, they also display quotations.)
This clock is made with just three major elements:
1. Wiseduino (with RTC and EEPROM on board);
2. 8x32 LED matrix display from Sure Electronics;
3. cardboard box as enclosure.
A few other required components are:
- a tilt sensor (or tilt ball switch);
- a USB cable, to power the clock.
Step 1: Assembling Wiseduino
Wiseduino can be bought as a kit here. The kit contains the following components:
- PCB (black);
- ATmega328P microcontroller programmed with the bootloader;
- 28-pin socket for the ATmega328P chip;
- 16MHz resonator for the microcontroller;
- DS1307 real time clock, with 8-pin socket;
- 24LC256 EEPROM, with 8-pin socket;
- 32768Hz crystal for the RTC;
- CR1220 coin battery and battery holder;
- 6-pin right angled male header (FTDI connector);
- 40-pin female header;
- 4 resistors 10K;
- 4 decoupling capacitors 100nF;
- 2N2222 transistor;
- power micro switch;
- 2-pin polarized male header (power connector);
- power jack with cable.
To assemble Wiseduino, follow these mini-steps:
1. Solder the IC (integrated circuits) sockets first. Place them correctly, so their notches match those in the silkscreen.
(This will be helpful later, when the ICs are to be inserted into their respective sockets; their notches should match those in the sockets, which match those in the silkscreen, got it?)
2. Solder in place the battery holder. (photo 1)
3. Solder the power connector, then the FTDI connector. (photo 2)
4. Solder the micro switch on the pads. Since this is an SMD (surface mounted device), use this technique: put some solder on one of the pads; place the switch over the pads, then solder the pin which is over the "loaded" pad. Once in place, solder the remaining pins.
5. Solder the four identical (10K) resistors in their places. These are the only resistors on the board.
6. Solder the four decoupling capacitors. Again, they are the only capacitors on the board.
7. Solder the 15MHz resonator.
8. Bend 90 degrees the 2 pins of the small cylindrical crystal (32768Hz), then solder it so it is parallel and close to the board. (photo 3)
At this point, we would have a few more steps to a complete assembling. But, for this project, we don't solder the female headers and neither the transistor.
What is left to be done is:
9. Insert the integrated circuits in their respective sockets, matching the notches (as mentioned above).
10. Insert the coin battery in its holder.
Next, we need to "hack" Wiseduino a bit, to install the tilt switch and to solder the ribbon cable for the display.