Um...Yo...

Share unrelated electronics stuff, ideas, rants, etc!
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Seanbot
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Joined: Sun Mar 14, 2010 6:14 am

Um...Yo...

Post by Seanbot » Sun Mar 14, 2010 6:20 am

Ah, Hi.
I'm Seanbot, and I've been checking out uzebox (Fuzebox really) for a while now, I've grabbed the Uzem emulator, and have been having fun with it.
My biggest problem I guess is my rudimentary skills with electronics, and low level computing. I'm probably going to get yelled at, but it's something I'd like to learn more about, and I don't know where to go. I've done some soldering kits before, and know what most components do, and I plan on getting the Fuzebox kit soon.
hello, I guess.

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D3thAdd3r
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Location: Minneapolis, United States

Re: Um...Yo...

Post by D3thAdd3r » Mon Mar 15, 2010 6:42 am

Hey Seanbot, glad to have you aboard. Uzebox is a great project to expand on your knowledge of electronics/computing, and you're having fun besides. So two birds with one stone there. Any specific questions be sure to ask, someone should have an answer for you.

Seanbot
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Joined: Sun Mar 14, 2010 6:14 am

Re: Um...Yo...

Post by Seanbot » Mon Mar 15, 2010 8:05 am

I'm just wondering what kind of reading material I should check out, I've been looking at the schematics, and I'm a little confused by the resistor thing that I believe is a DAC array? Furthermore I don't think I quite understand the AVR, or a lot of the theory behind most electronics.
Eh, I don't even know enough to know how little I know.

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paul
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Location: Brisbane, Australia

Re: Um...Yo...

Post by paul » Mon Mar 15, 2010 8:27 am

hi Sean.

I'suggest you continue to experiment with the emulator and check out the wiki for other intro material.

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D3thAdd3r
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Re: Um...Yo...

Post by D3thAdd3r » Tue Mar 16, 2010 5:05 am

On the R-2R DAC, you'll notice there are 3 outputs R,G,B which connects to the AD725 which converts it to a usable signal by the television. Two 3-bit "sub-ladders" for Red and Green and one 2-bit for Blue. This give the Uzebox it's 256 color capability where 0 = BLACK ... 255 = WHITE. You'll see the DAC is just a series of resistors with different values, and 8 pins/bits connect to the color DAC overall. Some pins output has to go through twice as much resistance as others, thereby it creates a less significant(half) change to the output as opposed to ones with lower resistance which have a more significant effect. So the analogue output is is linear to the binary sum of the port pins output. If you don't know how binary works, check out Jhyasaun's binary guide and those concepts should make sense. The Atmega 644 has four 8 bit ports that it can use to interface with other things(controllers,SD cards,PWM sound output,etc), and software can either write bytes on the ports or read bytes off them. So when you connect: Port->DAC->AD 725 you can send bytes(at appropriate timings) representing colors and they will be displayed on the television(a bit of a simplification). This process is handled by the kernel and if you just want to program games or build the circuit, you can pretty much forget about that detail. Off the top of my head there are only a few other basic constructs like decoupling capacitors, etc and you'll understand them more as you encounter and read about them.

Really google is your best friend when getting started, you should be able to learn everything you want. http://www.seattlerobotics.org/guide/electronics.html might be good start or lots of others, but I don't really know where you are at to begin with. I figure any time you hear a term you don't understand, research it until you do, and your knowledge will start cascading rapidly leading you to other areas of research(the ones you don't know that you don't know about :) ). Your thread, so anything you just can't figure out ask and someone will probably start throwing terms at you, with inadequate explanations, to go find ;)

Hope that helps a little, even with the generic "use google" clause. Per curiosity, do you have programming aspirations or are you mainly interested in the electronics side?

Seanbot
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Joined: Sun Mar 14, 2010 6:14 am

Re: Um...Yo...

Post by Seanbot » Tue Mar 16, 2010 6:34 am

Well I would say that I am a programmer, I'm not too bad, but I'm not an expert.
I have done Electronics projects in the past, mainly Jaycar Shortcircuits (if you know what those are) when I was like 9.
Well google is a good place, insofar as how much about electronics I know, I guess I know what some common components do; Resistors, capacitors, diodes, LEDs, switches, I'm a bit shaky on transistors, processors, transformers and the like. There is quite a bit about grounding and the path of electricity that I don't understand.

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D3thAdd3r
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Re: Um...Yo...

Post by D3thAdd3r » Tue Mar 16, 2010 9:09 am

You could build your Uzebox on a proto/bread board so you can easily experiment and learn even with a self written program to try ideas. Just compare electricity to something you can visualize. I find pneumatics or water is very analogous, everything will seek the path of least resistance and equilibrium, capacitance takes the form of time/versus space/pressure, a lot of examples will work. Basically learn or get a reference to all the basic resistance/capacitance/etc equations, look at data sheets, schematics. Maybe try your hand at a simple game/program, might learn a lot when you can "see" how your program is actually working on a machine you built yourself. Rewarding at the very least.

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