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2bit computer

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i am going to make a 2bit computer,it is a simple relay based study project.i will keep updated!


buy parts:
4 pole 12V relay*20
relay socket *20
lots of wires
1 pole switch*10
i think these parts is enough.


received all parts,drawn sch file,the attached picture is version0.1.
it is a very simple full adder machine.because i want to teach my son the binary system,he is only 5years old,at first i do not want make things too complex.the design based on harry's(http://web.cecs.pdx.edu/~harry/Relay/)1bit relay adder.i added I/O system(keep simple,just switch and LED)so we can watch how the machine operation.

the design have not test,i will do it weekend.


2bit relay adder test ok.there are small mistake in the sch v0.1.i updated v1.
i take some photos of the adder's running.see attached.
the below is 10+10=100

the below is 10+11=101

i have design a DTL baesd 1bit adder,this include 9*transistors and 27*diodes.there are nine NAND gates for one bit add.i have build a real thing,no test yet.see below.


i completed the DTL based ALU,and i built two register.

two 4bit register,the bus driver is 74hc244.


finally,i made a simple 4bit cpu.this is a HAND operating cpu.

there are four data input button(gray)and six instruction button(blue) on the panel.five led for result show.

the below is hand made ALU.this block like 74181 chip.

cpu structure show below.

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W, O ,W... wow

This is really a fine project you have here! I always wanted to make a full relay computer with a GPU and ram and all. I used to have the schematics for it even. Anway, considering adding ram or using a two's complement numbering?

Keep up the good work!



i think you mean 10x10=100 you said 10+10=100

10=2 100=4

Looks like both are right.

this is a 2bit binary adding machine.

sorry it looks like a mistake i dont know binery  

Get out there and learn binary NOW. No robot builder can get the job done without programming. No programmer is complete without knowing how to do basic maths in binary, a little bit of hexadecimal is also a must.