Arduino Nano 3.0 
Monday, March 29, 2010, 01:23 AM - Electronics
The Arduino Nano 3.0, available at MakerSHED for $35, is PCB-mountable, small footprint Arduino with an Atmega328 chip and a mini-USB connector.
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One Week with a Nexus One Google Phone 
Monday, March 29, 2010, 12:27 AM - Electronics
As soon as Google announced the availability of a version of the Nexus One phone that works with AT&T's 3G frequencies, I got one ($530 direct from Google). This is the best phone every made by a long shot. Waaaay better than the iPhone.
The 800x480 OLED display is fantastic. With 800 pixels, it's wide enough to display web sites without weird reformatting. The 1GHz snapdragon ARM-based CPU is very fast, and the browsing experience is fantastic (and it does have multi-touch pinching zoom). The Android 2.1 UI has all the buttons and functions in the right places. This is very much unlike Android 1.5 on my Samsung Galaxy 7500, which was incredibly clunky, slow and unresponsive.

As Wired magazine says, there are 3 types of "flashes" that the Nexus one supports and the iPhone doesn't: Adobe Flash (to view YouTube videos and browse the web), an LED flash for the camera (5MP with autofocus), and a microSD slot for a flash card. My Nexus One came with a 4GB microSD, which I replaced by an 8GB.

It has been said that the Nexus One sales have been slow, but it's because the US cell market is so fragmented: T-Mobile uses GSM for 2G and standard frequencies for 3G, but their coverage sucks; Verizon has good coverage and uses normal 3G frequencies, but they use CDMA for 2G instead of GSM like everyone else; AT&T uses GSM and has good coverage, but they use weird frequency bands for 3G. Bwaaaaah!

Why couldn't the US government do its job and establish standards, as Europe did?

In any case, the Nexus One now works with a carrier that actually has decent coverage. The apps are fabulous (even has a VNC client), but I haven't been able to figure out how to use the 3G connection from a laptop through BlueTooth.

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JeeLink: Arduino + RF 
Monday, March 29, 2010, 12:20 AM - Electronics
The JeeLink v2 is an Arduino with an RF link package in a tiny form factor. It costs about 30 Euros. It can be paired with an 18 Euro JeeNode, also an Arduino + RF module.
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6 DoF IMU + Arduino 
Sunday, December 20, 2009, 04:02 PM - Electronics
The DIY Drones store has a very useful piece of hardware: the ArduIMU+ v2. It's an Arduino-compatible board with a 3-axis accelerometer chip and a 3-axis gyro chip with appropriate filters. It also has a connector for a GPS module (with a 4Hz refresh rate). All of this for $100 (plus $90 for the GPS). Very useful.
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Modifying an ESC for digital speed control 
Monday, November 30, 2009, 03:50 PM - Electronics
The tight control loop of quad-rotor helicopters requires very fast response from electronic speed controllers (ESC). Unfortunately, all hobby ESC are PWM controlled, and can't accept pulses at a high rate. This introduces lags in the control loops. Some folks have figured out how to hack commercial hobby ESCs so as to control them with an I2C digital interface. There is a whole thread about this on RC Groups, as well as a PDF file with detailed instructions, and schematics.

The alternative is to buy an I2C compatible ESC from YGE: 60 Euros (about $90) for the 18A YGE-18i, or 70 Euros ($115) for the 30A YGE-30i. Ouch!

Speaking of which, for you ESC DIYers, Fairchild has a 40V, 20A, Dual N & P channel mosfet pair, the FDD8424H (available at Mouser for $0.86).

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ttymidi: serial/usb to MIDI for linux 
Saturday, October 17, 2009, 10:26 PM - Electronics
TTYMIDI is a linux hack to allow any serial or serial/USB device (such as the Arduino) to produce MIDI events compatibel with ALSA in Linux. This makes it easy to turn any Arduino-based hack into a MIDI controller.

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A week with the Samsung Galaxy i7500 Android phone 
Monday, September 7, 2009, 01:22 AM - Electronics
About a week ago, I got an imported Samsung Galaxy i7500 Android phone from MobileCityOnline.com. This is a $600 unlocked import model built for the European market.
T-Mobile isn't schedule to distribute the phone in the US until later this fall, and I use the phone with AT&T anyway (since I don't get any T-Mobile signal at home).

Problem #1: The main issue with using the Galaxy with AT&T (or any existing Android phone for that matter) is that AT&T uses unconventional frequencies for 3G that are not supported by any Android phone. Hence, using an Android phone with AT&T means being restricted to 2G and Wifi. It sucks, but it sucks less than having no signal at home.

Setting up the phone to work with an AT&T SIM card posed no problem. The Settings->APN entries are as follows:

Name: anything_you_want
APN: wap.cingular
Username: wap@cingulargprs.com
Password: cingular1
MMSC: http://mmsc.cingular.com
MMS Proxy: wireless.cingular.com
MMS port: 80
MCC: 310
MNC: 410

Problem #2: the version of the firmware/software installed on the unlocked Samsung phone is essentially unusable in the US. There is no "Market" app to download software from the Android market, no automatic switching of the screen from portrait to landscape, no access to the accelerometer and magnetometer. Fortunately, the fix is easy: you can flash the latest version of the firmware (H7), and everything will work fine. The procedure is quite simple and described here. You will need a Windoze machine to run the MultiOdin ROM flashing utility.

Thank you kam187 from androidforums for the trick.

The phone is simply fantastic.



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mbed: ARM7 microcontroller with online toolchain 
Thursday, August 27, 2009, 03:04 AM - Electronics
The mbed microcontroller uses such a cool new concept that one wonders why we haven't seen this before: an online C++ toolchain/development suite. The mbed microcontroller board uses an open design built around a 60MHz NXP LPC2368 ARM7 CPU (datasheet) with 512KB flash, 32KB RAM, USB 2.0, 10/100 ethernet, SD/MMC interface, 2xSPI, 2xI2C, 3xUART, 1xCAN, GPIO, 6xPWM, 6xADCs, and 1xDAC. The library apparently contains simple Arduino-like functions for I/O and such.

It's still in beta at the moment, and the board is supposed to cost about $65 50 UK Pounds, or about $85.

There is a number of articles on the mbed at Elektor, and at Circuit Cellar (PDF).

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Maple: ARM-based Arduino coming soon 
Saturday, August 22, 2009, 12:46 PM - Electronics
The Leaflabs blog has a post about the prototype of a rather appetizing Arduino-like micro-controller board built around an STM32 ARM Cortex-M3 from ST Micro.

The folks at Leaflabs apparently intend to make the board work with the Arduino software suite, and implement an Arduino compatible library. Many of us are drooling at the prospect of an ARM-based, $40 Arduino-quasi-compatible board. It would enable projects that are out of reach of the current Atmega-based Arduino, such as real-time audio processing. It would certainly help that the STM32 has three super-fast 12-bit ADC, as well as two 12-bit DACs! Hello Arduino-based synthesizer modules!

It's not clear which the 3 zillion versions of the STM32 the board uses.

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Stickduino now uses Atmega328 
Wednesday, July 15, 2009, 12:10 AM - Electronics
The new Stickduino Arduino clone as been upgraded with the new Atmega328, so as to match the latest version of the "official" Arduino. The price is still below $20.

Strangely enough, the stickduino website makes no mention of the change!

How do I learned about it then?

Well, I just received a new batch of Stickduinos and tried to program one, but the program wouldn't upload (I kept getting "stk500_recv() programmer is not responding" from avrdude). I started looking on the web for answers, but couldn't find anything. After fiddling for a while, I looked closely at the board, and realized it had an Atmega328. I configured the Arduino IDE for the new Duemilanove Arduino, and everything worked perfectly.

Still, I'm surprised the stickduino people don't mention this anywhere.

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XBee carrier boards 
Thursday, March 26, 2009, 02:50 AM - Electronics
The Makershed has a new XBee adapter for $10 with 10 pins, some which directly fit in an FTDI serial USB adapter cable. It includes level shifters and a 3.3v regulator and can be plugged into a proto board.

Newmicros also has an XBee USB dongle, for $40.

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Cheap dual wireless cameras 
Saturday, March 14, 2009, 09:09 PM - Electronics
Intelspy sells a surveillance system with two wireless cameras and a 2-channel receiver for $130. The interesting thing is that the claimed range is over 500m.
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Arduino-based magnetic levitation 
Saturday, March 14, 2009, 09:00 PM - Electronics
A cool little hack in which an Arduino is used to levitate a magnetic object and regulate its distance from the levitating electromagnet.
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Arduino JEP shields 
Monday, March 9, 2009, 10:04 PM - Electronics
This page has a bunch of interesting prototyping shields for the Arduino, including relays, power FETs, motor drivers and such (via Makezine blog).


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MIDI library for the Arduino 
Tuesday, January 27, 2009, 11:15 PM - Electronics
Title says it all. Get it here.

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Arduino-based MIDI -> control voltage converter 
Monday, January 12, 2009, 07:22 PM - Electronics
This page (with an interesting domain name) describes a simple MIDI->control voltage converter that can be used to control analog synths from MIDI controllers. The contraption contains an arduino and an Analog Device AD5668 16-bit digital to analog converter chip. this chip has 8 independent analog outputs with 16 bit resolution, and uses an SPI (serial) interface. The chip can be had for $25 from DigiKey.

The most complicated part is to figure out how to talk to DAC chip, but the Arduino sketch source code says it all.
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