Application 3997

I have built a simple 4-bit calculator that can add or subtract numbers from 1 to 9. I used a simple ALU with a couple of fulladders (not very convenient fulladders), and some subtractors (still not very convenient). I don't know how to make good fulladders. I used an encoder just like the one you'd see everywhere, and a decoder, just like the one you'd see everywhere. I used a 7-segment number display to display each number: Number 1 +/- Number 2 = Number 3. Currently I am working on an 8-bit calculator. I came up with a thing I call an "alternator". It is an "addon" to the buffer which, whenever it receives a signal, changes the output by 1. It uses the classic repeater locking buffer, a NOR of each output of the buffer, an AND gate that compares the NOR of each output and the input. What it does, is when there is no output in the buffer, the next time it receives a signal, it makes the first output a 1. Then it just cycles through all the outputs, and when it reaches the last one, it turns off. I use that in my word processor project for inputting different letters. The word processor will take a lot of work, because I do not know how people make word processors, but I will make a tower with 30 t-flipflops. 27 will represent letters of the alphabet, 1 will represent a space, and the other two: fullstop and exclaimation mark. Each tower will represent a character. Then I will use the alternator to, whenever you press a letter, switch to the next letter. Then once all of that is done, the output of the word processor will be a ticker display, and each output of each t-flipflop tower will lead to one of the letters in the ticker display. I have only gotten to making the alternator, and currently it has only 10 characters. I also made different stuff such as the 3x3 flush door, multi-piston extenders, and so on.