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Searching for: electronics
Arduino Random Number Generator [01257868826]
Random Number Generator Schematic
Inspired by other designs I've seen online, most directly Rob Seward's design , I decided
to build my own random number generator based Will Ware's " avalanche noise in a
reverse-biased PN junction " (try this mirror of Will Ware's page )
Two-element capacitative touch sensor [01219970985]
Touching the sensor ( M ) ( L )
The finger position readout
As a distraction from my real project -- building a lightbulb alarm clock for
the coming winter -- I've been playing with capacitative sensors. My first
effort was a wire taped to a piece of metal foil, and that worked OK. The
present iteration is a two-element touch sensor on a milled circuit board.
The sensors are each about 1 " by .5 " and are connected to the arduino by a
3-pin header. The components on the board are very simple -- two 1M resistors.
With a combination of software running on the microcontroller and in the PC,
the sensor is made into a virtual slider.
Bah, it's garbage [01210042966]
1MHz+ Quadrature Divider for attiny13 [projects/01149348342]
Quadrature divider board. Actual size: .7x.4 inches (about 18x10mm)
This untested code, along with an Eagle schematic and board layout, are
for a quadrature divider that polls at over 1MHz. The R and S test points are
used to program the device.
Like the 400kHz triple divider , this program uses a state table generated by " mkstate.py " , and
is GPL software.
For real-world use, external pull-ups should probably be added to the board's
input side, according to the directions of the encoder manufacturer.
400kHz Triple quadrature divider for atmega8 and quadrature state table generator [projects/01149271333]
I promised a single, 800kHz quadrature divider for the attiny13.
Well, I haven't done that yet (I don't have any attiny13s to test on anyway),
but I have something else instead. Update, 2007/01/04 : Want true high-resolution PWM
and multi-MHz quadrature counting with emc2, for under $100? Try this !
Creating a Quadrature Divider: What Won't Work [projects/01149094674]
A proposed quadrature divider circuit, and a
waveform that it will treat incorrectly
As an improvement to the simplest possible
closed-loop servo system , I've been trying to design a circuit that will
function as a quadrature divider: the input and output are both quadrature
waveforms with the same direction, but the output waveform is 1/8 or 1/16 as
fast as the input.
Because emc2's encoder module poops out somewhere around 20 microsecond polling
intervals, an external divider is the only way to get accurate feedback from a
fast servo motor with a high-resolution encoder. Division by 16 lets the PC
see a 25kHz quadrature signal instead of a 400kHz one. For Chris's lathe
retrofit, the target speed is actually around 125kHz (1250 mm/min, 1mm/rev
leadscrew, 3:1 pulley, 500 line/rev encoder), but to keep it from being too
easy, he's going to do 3 such decoders on a single 16MHz atmega.
Many people seem to hit on the idea of using an up/down counter to process a
quadrature input. Chris and I managed to
convince a couple of bright guys on the #emc channel that this would work to
create a quadrature divider circuit. Well, it doesn't.
Two-axis servo schematic and board [projects/01148303608]
L298 single-sided board
I didn't originally include the
eagle-format schematic and board for this project. Well, here it is.
Parallel-port Two-axis PWM servo controller for Etch CNC [projects/01142347802]
ETCH Servo ( M ) ( L )
Inspired by discussion on #emc and by the fact that I'd already
bought two tiny servo motors , I've designed and built a two-axis PWM servo controller
with a parallel port interface.
First Interesting Strobe Photo [01135347558]
SOIC-8 to DIP adapter board [projects/01134834815]
4-axis half-stepping translator in AVR [projects/01129403515]
Chris started with a MAXNC 10 open-loop machine. The included driver
boxes (which we came to understand were complete crap) use one pin per winding.
This requires two parallel ports for 4 axes. So, a year or so ago, before he
switched to L297/8-based boards ,
I helped Chris design an avr-based translator
from step+direction pulses to the individual winding activation signals. Today
I'm posting the program, which I compiled with avr-gcc. In the future I might
post the board, which was a double sided design created in eagle.
a plug for Eagle3D [01117938653]
XY display update [projects/01117067802]
New CRT, new board, same software...
vgaxy -- create XY scope displays with your VGA card [software/01115603899]
Software for a virtual terminal and several other toys
Vector patches for xmame 0.94 [software/01115603825]
With this patch applied, xmame 0.94 does vgaxy-style output for display on an oscilloscope in xy mode
More vector game screenshots [01115494353]
Battle Zone ( M ) ( L ) I really should mention the website of Jed Margolin which has a lot of information about his time at Atari, including his work with vector games.
"Dithered" output increases resolution [01114979771]
MAME vector display on the oscilloscope [01114971365]
Asteroids ( M ) ( L ) Yep, it works. Too bad about the low resolution. More game pictures below the fold.
Working Z-axis [01114736689]
Vector terminal with Z-axis ( M ) ( L ) With a simple transistor, the Z axis works pretty well. The linearity is better now that I'm using some 10b2 tees and terminators (50 ohms) on the X and Y inputs, too.
Vector "text" display [01113752862]
Simulating a character-cell display ( M ) ( L ) Displaying a message, even.
Animated XY display [01113705217]
Not originally a raster game... ( M ) ( L ) It's an old-style " QIX " animation.
VGA to 'scope display [01113670404]
XY display of a cube ( M ) ( L )
The question on my mind was this: Where do I get a nice, fast DAC to run an XY display? How do I keep it fed with values? I discovered a very simple answer that I hadn't heard of before.
The hardware is dirt simple: Get a VGA to 5 BNC-connector cable. Plug your computer's VGA output into your scope. Now load a specially crafted image in a full-screen viewer
Regulated LED flashlight -- update [projects/01112559552]
TI serial-interface DAC [projects/01112140655]
Sine wave created by software running on an AVR with a look-up table ( M ) ( L ) I got this interesting little DAC working earlier tonight, with only a minimum of trouble. The code worked right the first time, but I got the hardware wrong ---I let the " power down/ " pin on the DAC float, which meant I got a mostly random square wave superimposed on the sine wave. Here's a crummy photo of my scope displaying a sine wave. The sine wave is generated from a 512-entry, 9-bit table in the AVR.
Regulated LED flashlight [projects/01111764189]
This new board is designed around the same MIC2570 boost-mode regulator , and is designed to fit inside a pocket-size tin .
Another constant-current circuit [projects/01111254927]
Here's a constant-current LED driver circuit meant for use with wall-wart power supplies
It's in a frame! [01109127822]
OK, so there are still some problems left. But this is exciting anyway.
Stippler: Turning photos into dots [01108611472]
A few weeks ago, I stumbled over a paper by Adrian Secord describing an algorithm to turn a greyscale image into stipples. Here are the results of my implementation of his algorithm. UPDATE: I added the original photo of Marie, as well as the version that was used as input by stippler.
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