I built this clock some years ago (in the 2005). It was a present for my son that has difficulties to wake-up in the morning. I decided to create a new kind of ringer, using a glass, a small cc motor and two small rubber balls tied to the motor axis. As cointainer, I used 6 “jewel case” for CDs and a lot of glue 🙂 as you can see in the picture below.
There are 12 leds for the hours and 12 for minutes, this means that they advance at every 5 minutes boundary. I think this is sufficient ; personally, I never say: “are twelve past ten”, but use an approximation like “are ten past ten” or “a quarter part ten”, depending from the minute (and… normally I say it in Italian, my native language). This clock uses always a defect approximation, but you can modify the C source to create your own version. The control buttons are for setting the current time, the alarm time and to stop the ringer. In the schematic there is a NiCd battery (4.8V) that recharges at very low current. This just in case the power fails ; an alarm clock MUST work even if there is no supply. Obviously, today the NiCd rechargeable batteries are obsolete, but you can modify the circuit (included in the downloadable file) to change the part used for charging. Also note that the microcontroller used for this project is the AT90S2313, that’s obsolete. You can simply interchange it with the modern and active ATtiny2313 ; remember to adjust the internal fuse pattern in order to achieve the external Xtal clock running (at 4.096 MHz).
The downloadable file ef093.zip contains:
– root_1_1.pdf , the electric schematic, page 1
– root_1_2.pdf , the electric schematic, page 2
– tn_roboclock.jpg , the picture of the roboclock realized by me
– a093mio.hex , the hex file ready to be programmed into the micro
– main.c , the ‘C’ source file for this device