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The Mechanical CPU Clock shows the basic building blocks of a CPU (ALU, buses,RAM,registers, and a Control Unit). It executes a set of instruction...
For a CPU to do any meaningful work, it needs to be told what to do. This comes in the form of instructions. For this wall clock I will only concentra...
We will now implement the primitive CPU instructions in hardware and program the CPU. I will use Autodesk Inventor for this mainly because of its grea...
Next, create a cut in the 12” disk encasing the envelope of the flip-flop, so that the flip-flop can move freely (parametric design makes this process...
Since we want our clock to count up to 12, we will need to represent 11 (0,1,...,11) in our register. Our flip-flop can only have two states, so we ca...
Next we will add another register (register C), which will also contain a copy of A. This register will be used for the EQUAL statement to check if re...
Next we will implement the DTD bit flag (the control unit) in the form of two tracks. If the ball goes on track A, then DTD is false. If its on track...
Programming the clock is achieved by routing the ball to specific locations. That is, we will “hard code” the program into the CPU. The ALU is going t...
Lastly we will add the bus on our CPU, to connect our registers together. As one of the registers changes, it will copy the data to the rest of the re...
Here is the final clock with all the appropriate labels. It works by executing the flowing code. 1: CHECK_DTD 2: JUMP 5 3: CLEAR 4: JUMP 1 5: INCREME...
Before building the clock, we can simulate the ball drop using the dynamic simulator in Inventor. Due to the complexity on the simulation (and my lack...
To lift the ball on track A or B we will use a lever with two magnets and a motor to rotate the lever once an hour. This will allow the ball to drop o...
Since we can also read out the current minutes by the position of the lever, we can place the minutes numbers on the clock face just like in a real cl...
We start building the clock by laser cutting the parts out of acrylic. You can use what ever color you like, but some colors show up better then othe...
The buses are made out of piano wire. Note the angle band at the top, which will be used to adjust the final length. Attach the buss wire to the flip...
Place the ball inside and attach the face to the backplate and tracks with screws.
The motor used for this clock is a 1 RPH (1 revolution per hour) timing motor, which gets very hot. To dissipate some of the heat, we will base a case...
Here is the final clock mounted on a wall.
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Posted:Apr 15, 2012
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