We’re pretty spoiled these days in that hobby electronics has made a lot of cool tools available on a budget. It’s hard to think of a better example than a logic analyzer, which you can get for a day or two of pay. Consumer-level devices just didn’t exist until a few years ago. [Jouko S] has this HP16500B industrial grade logic analyzer in his shop. It’s from the early 1990’s and it’s got a ton of features. Grabbing a still functional yet super-old model used to be the only way for hobbyists. But one thing you won’t find on it is the ability to connect it to your USB port to get screen captures. Younger readers might not recognize the slot at the top for magnetic media called a floppy disk which is the in-built way of recording your sessions. He set out to find an easier way to get color screen captures and ended up adding RS-232 control to the old hardware.
There is a 25-pin port on the back of the old hulk. But it is a female connector and he didn’t have the adapters on hand to make it work with his serial-to-USB converter. During development he used a breadboard and solder-tail connector to patch into the necessary signals. This was all hooked up to a Raspberry Pi which he planned to dedicate to the system. It worked, and he was able to use an interactive terminal for the rest of his sleuthing. With much trial and error he figured out the commands, and wrote some Python code for the Pi side of the equation. He can now pull color screenshots with ease thanks to the utilities available in the Python Imaging Module.
[Reza’s] methodical investigation of this remote controlled outlet let him patch in with an Arduino using a 433 MHz transmitter. This is a single-device unit, but the techniques used here should allow you to take control of wireless rigs that have multiple modules to control many devices.
We’ve seen some folks at our local hackerspace try to patch into the remote control itself. That used some type of weird button scanning (not just connecting a pin to ground or voltage) and didn’t pan out. [Reza] doesn’t even crack open the case of either of the units seen above. Instead, he goes straight for a wireless receiver he had on hand, using a logic analyzer to capture the signals coming from the remote.
Once he had a good snapshot of the signals sent when pressing the on or off button of the remote he set out to replicate it in his Arduino code. His function called setStateWithDelay takes three parameters: the transmit pin, the level (high or low), and a number of milliseconds to delay. Each signal calls this function many times, but working the bugs out is pretty easy; just capture the signal with the logic sniffer and compare to the stock remote.
If you have a Stellaris Launchpad sitting around, have a go at using it as a logic analyzer
The Stellaris logic analyzer is based upon this earlier build that took code from a SUMP comparable Arduino logic analyzer and ported it to the much faster and more capable Stellaris Launchpad with an ARM Cortex 4F processor.
This build turns the Launchpad into a 10 MHz, 8-channel logic analyzer with a 16 kB buffer comparable with just about every piece of software thanks to the SUMP protocol. Even though the ARM chip in the Launchpad isn’t 5 Volt tolerant, only pins 0 and 1 on Port B are limited to 3.6 Volts. All the other pins on Port B are 5 Volt tolerant.
Not a bad piece of work to turn a Launchpad that has been sitting on your workbench into a useful tool.
[Gabriel Anzziani] has just unleashed a newer, more convenient version of his Xprotolab portable oscilloscope, logic analyzer, and function generator. It’s up on Kickstarter, and the price is actually very nice for a tool of this caliber.
We first saw the Xprotolab early last year and ran into [Gabriel] at this year’s World Maker Faire in New York. On both occasions we were impressed with the size and capability of this very, very small OLED-display oscilloscope and general breadboarding Swiss army knife.
The Xprotolab features a two-channel, 200 kHz oscilloscope, 8-input logic analyzer, and an arbitrary waveform generator that should be good enough for all your breadboarding adventures. On top of that, the Xprotolab can sniff SPI, I2C, and UART protocols, and even has a small spectrum analyzer tucked away in a device small enough to lose in your pocket.
The updated-for-Kickstarter Xprotolab features an enclosure with a LiPo battery good for 12 hours of use per charge. Sure, it’s not a bench full of old HP and Tektronix gear, but for the budding maker, this seems like a very useful tool indeed.
With a surplus of 3D printers at this year’s Maker Faire, it’s really surprising to see the most talked about tool among the makers is a simple oscilloscope.
[Gabriel Anzziani]’s Xprotolab is an extremely small oscilloscope, function generator, logic analyzer, and general 128×64 OLED display is the perfect addition to your next prototyping project. With its breadboard friendly format and USB output, it will dutifully serve as a 200kbps oscilloscope, 8 channel logic analyzer, or as seen in the video above, the perfect interface for a Wii Nunchuck or just a simple digital Etch-a-sketch.
In the video above the fold [Gabriel] shows off the functions of his tiny, if somewhat limited, OLED oscilloscope.
Here’s a 6-channel logic analyzer shield for the MSP430 Launchpad. It manages an eyebrow-raising 16 million samples per second. The prototype seen above is made on a hunk of protoboard with point-to-point soldering. [oPossum] did lay out a PCB — which is just 50mmx50mm — but has not had any produced quite yet.
He calls it the LogicBoost, and based it on the the LogicShrimp design. The sextuplet of 8-pin chips are all SPI RAM. These are responsible for storing the samples, with a 74HC573 latch routing the traffic. The MSP430 chip provides the SPI clock, and the Launchpad’s virtual com port can be used to push the data to a computer for graphing. That’s a bit slow so [oPossum] also included an optional header for an FTDI board that will do a faster job. The sample rate can be adjusted by tweaking the internal oscillator setting of the chip; there’s plenty to choose from so it will work for just about any purpose (as long as you don’t surpass the 16 Msps speed limit).
[via Dangerous Prototypes]
Sooner or later, you’re going to need a logic analyzer. If you don’t have a Bus Pirate or Logic Sniffer lying around, [Joonas] has a great MacGyverism that turns an oscilloscope into the simplest logic analyzer ever.
The basic premise of the build is tying four digital lines to the analog input of an oscope. This is done with a 74HC126 buffer that provides a high impedance input for the logic probes and outputs the four-bit status of each logic channel. With a few resistors in an R-2R network, the state of four digital lines can be easily read.
[Joonas] included the source code to turn his Picoscope 2000 into a logic analyzer, but there’s no reason why this couldn’t be done with any digital scope that has a serial output. Not bad for a very, very simple logic analyzer – just one chip and a handful of resistors – that costs less than $5.