Wireless 4 Channel Temperature Monitor From Arduino Libraries

Say what you will about the Arduino platform but there certainly are a ton of libraries one can choose from. That is precisely what [Dan Julio] set out to do when building his slick looking 4 channel temperature monitor. The monitor consists of an Arduino RBBB, 2×16 character LCD and four DS18B20 1-wire digital thermometers. [Dan] also includes a bluesmirf to interface with an OS X monitoring program.  Using libraries for the Bluetooth, LCD, and temperature monitors the Arduino code is only about 200 lines, and pretty easy to follow. Check out more at [Dan]’s site.

If you’d like more temperature sensor projects check out this mug or this PIC based monitor or perhaps you’d like to keep it in the Atmel family.

BAMF2011: Google’s SKPR Bot, Not For Arachnophobes

Google’s Maker Faire exhibit space is swarmed with robots…er, androids. Amidst some cool bipeds and Segway-balancers, our inner sci-fi nerd was most smitten with this hexapod design, which they’ve dubbed SKPR Bot. The “Skipper” is on hand to showcase the ease of various Google technologies: SketchUp, Android OS and the Android Open Accessory Development Kit. The whole project came together in less than six weeks.

18 servos are mounted to a framework designed in SketchUp and laser-cut by Ponoko. The low-level servo PWM control is handled by the Dev Kit (essentially a rebadged Arduino Mega, as we’ve seen), while an Android OS phone provides a slick GUI and handles all the inverse kinematics calculations required as the robot takes each step. The coolest bit is that it’s all up for grabs. At this moment you’ll have to scrounge around the ’net a bit to find the plans and code, but some time post-Faire they plan to bring everything together at the SKPR Bot site.

BAMF2011: ChipKIT Is Arduino To The Power Of 32

If you’ve been hungry for more power for your microcontroller projects, but reluctant to dump your investment in Arduino shields or the libraries and community knowledge that go with them all, Digilent has you covered. Their new chipKIT boards are built around the Microchip PIC32 MCU…a powerful 32-bit chip that until recently was left out of the cross-platform scene. A majority of code and quite a number of Arduino shields will work “out of the box” with the chipKIT, and the familiar development tools are available for all three major operating systems: Windows, Mac and Linux.

We first mentioned these a couple weeks ago, but the software was unavailable at the time. Seeing the development tools in action was quite unexpected…

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Xoscillo Turns Arduino In An Oscilloscope

If you don’t have an oscilloscope you’d be surprised how many times you find yourself needing one. But if you have an Arduino on hand, the next time you might be able to get by with this software suite that can use a development board as oscilloscope inputs. The project is called xoscillo, and it allows an Arduino, or a Parallax USB Oscilloscope, to probe the signals while a computer does the heavy lifting.

The Arduino can be used for up to four input channels at 7 kHz. It’s possible to probe seven signals at 4 kHz as well. But the main feature that caught our eye is the ability to use several Arduino boards at one time in increase the number of channels available to you.

Granted, this is pretty slow for many digital electronic troubleshooting needs. But at least it’s something you can pull out when you just don’t have any other ideas about what is going wrong with your prototype circuit. We’re sure that sooner or later you’ll break down and buy a proper hackable oscilloscope. After all, your Arduino is probably already occupied as an I2C sniffer.

[Thanks Adam]

Arduino I2C Sniffer

[Johngineer] found himself in need of an I2C sniffer, but didn’t have one available. Necessity is the mother of invention, so he put together this I2C sniffer sketch for Arduino. The arduino will record what is going on for a set time interval, then dump the data via serial as a .csv. You then have to plot it to see what is going on. [Johngineer] recommends Livegraph, since it is portable and easy. As you can see in the code, the time interval is adjustable, but you have the physical limitations of the RAM on the board to consider. This seems like a pretty handy piece of code stored around, effectively giving you a passable I2C sniffer in a pinch.

Arduino Arcade Rom Dumper

[Vincenzo] wanted to read some 82S129 bipolar proms, and why not, they were very common in the 1980’s arcade scene. The problem is that its kind of an odd ball part now, and typically only (even) more expensive EPROM programmers can read them. An Arduino, breadboard and some quick scripting quickly takes care of that problem with this Arcade Rom Reader.

You stick the prom in your breadboard, and wire it up to the appropriate ports and pins of the Arduino, which bit bangs the prom and returns the results though the serial connection of the Arduino. Using a terminal program on the pc side you capture the text and use a script to convert the ascii values into a binary nibble format and save as hex.

This makes it much easier for us to dump roms from old arcade boards, because you never know when you might run across an old Polybius arcade board on your next outing to the salvage or scrap yard.

Join us after the break for all the details and as always comments!

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Fixing Arduino’s Serial Latency Issues

arduino_latency

[Paul] wrote in to tell us about some interesting Arduino latency issues he helped nail down and fix on the Arduino.

It seems that [Michu] was having some problems with controlling his Rainbowduino project we featured earlier this year, and he couldn’t quite figure out why he was experiencing such huge delays when sending and receiving data.

Searching online for answers turned up very little, and since [Michu] was using Processing, the pair designed a set of tests to see what kind of latency was being introduced by Java. Pitting an Arduino Uno and an Arduino from 2009 against a Teensy 2.0, the tests gauged the latency of native data transfers versus transfers facilitated by Java via the rxtx library it uses for serial communications.

The results were pretty stunning. While both of the Arduinos lagged behind the Teensy by a long shot, their latency values under Java were always 20ms at a minimum – something didn’t add up. [Michu] poked around in the rxtx code and found a mystery 20ms delay programmed into the serial library. It made no sense to him, so he changed the delay to 2ms and saw a drastic increase in performance when transferring less than 128 bytes of data.

The pair’s fix doesn’t seem to affect latency when larger amounts of data (>1kB) are being transferred, but it makes a world of difference when manipulating smaller chunks of data.

For the sake of disclosure, it should be noted that [Paul’s] company produces the Teensy mcu.