A place to learn about coding, making things, and stuff that strikes my fancy.
So here's where the next video stands. First, as I noted in a previous blog post, I've settled on an 8080-like MPU with 6 8-bit registers and an internal 8-bit bus. Now to make an internal 8-bit bus work, you nee a tri-state gate, a logic circuit which can be used to disconnect our logic... Continue Reading →
So one of my goals of my series "Introduction To Digital Computers" is to show the design of a computer that can be built entirely out of NPN transistors. The idea is that by showing the design of a digital computer from the absolute ground up--from something you can hold in your hands rather than... Continue Reading →
I originally planned to try to get this video out by the end of October. But I just returned from a two week trip to Spain and the south of France--and before I release a video which starts to tie together the registers developed in the third video with the arithmetic logic in the second... Continue Reading →
It's been about a month, and here's the third video explaining how computers work from the ground up. In this third video I discuss flip flops. Starting with two not gates hooked together I discuss how a bi-stable circuit operates, extend this using NOR gates to Set/Reset flip flops, build data flip flops, edge-triggered data... Continue Reading →
I feel like, with making the first two "Introduction to Digital Computers" videos I've gained a superpower. And I've used that power to help me visualize and solve another problem I was having, figuring out the shape of spur gears (and eventually, internal spur gears, the next major feature I'd like to add to the... Continue Reading →
I've come to realize making something from scratch winds up building a bunch of prototypes as you both perfect the plans and figure out how to make the parts. And in my case, while the plans may be great--my ability to machine parts is... shall we say questionable? At any rate, I have a second... Continue Reading →
When we used NPN transistors to build our logic gates, it implies they can be used for building bigger things. In this video I've built a full 1 bit adder from our second Introduction video, entirely from discrete transistors. Build 8 of these--and you have an 8-bit adder. The show notes include the complete circuit... Continue Reading →
It took another couple of tries, and the trick for these gears was to get the outer diameter to within 0.002". Further, it required depthing the teeth to 1/32" == 0.625" (the precise measurement of the depth of the teeth) rather than cutting them a hair deeper. And I'm suspicious the Sherline divider may not... Continue Reading →
It probably doesn't help that I have no idea what I'm doing. Though I do have all my fingers and toes. So there's that. So today, after getting the M3 to M2 adapter, the M2 to Sherline adapter, and hooking up the Sherline 4-jawed chuck to the larger 7" lathe, I went to round the... Continue Reading →
So if you've been watching my Quick Videos you know I've been building a lot of circuits on prototype boards. I also took the liberty of 3D printing a couple of useful tools to help measure and bend wire. The first on the left helps measure lengths of wire; each wire is measured in each... Continue Reading →
The Hacking Den 
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