serial

189 Articles

Hacking Into Your Router’s Administrative Interface

June 9, 2011 by 21 Comments

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[Arto] recently upgraded his home Internet subscription from an ADSL to VDSL, and with that change received a shiny new ZTE ZXDSL 931WII modem/wireless router. Once he had it installed, he started to go about his normal routine of changing the administrator password, setting up port forwarding, and configuring the wireless security settings…or at least he tried to.

It seems that he was completely unable to access the router’s configuration panel, and after sitting on the phone with his ISP’s “support” personnel, he was informed that there was no way for him to tweak even a single setting.

Undaunted, he cracked the router open and started poking around. He quickly identified a serial port, and after putting together a simple RS232 transceiver, was able to access the router’s telnet interface. It took quite a bit of experimentation and a good handful of help from online forums, but [Arto] was eventually able to upload an older firmware image to the device which gave him the configuration tools he was looking for.

Aside from a few Ethernet timeout issues, the router is now performing to his satisfaction. However, as a final bit of salt in his wounds, he recently read that the admin panel he was originally seeking can be accessed via the router’s WAN interface using a well-known default password – frustrating and incredibly insecure, all at the same time! He says that he learned quite a few things along the way, so not all was lost.

Compaq Portable III Rises Again For A Noble Cause

June 9, 2011 by 36 Comments

[Autuin] found a Compaq Portable III destined for the scrap bin at Free Geek Vancouver. Upon seeing it he realized that it still had some fight left in it — perfect to go up against the tyranny of hipsters and their shiny Macbook Pros at his local coffee shop.

Unfortunately, being a 286, the computer couldn’t do much. He could take the usual route; which is to remove all the internals, and use the vast amount of space to fit a more modern computer inside. However, he decided to go a different path and save the internals, leaving it in original working order. The computer didn’t have enough power to browse the web, but it had just enough room to fit a small single-board computer inside, to which he could connect through serial. He hasn’t taken it down to the coffee shop yet, but we’re hoping for a few horrified hipsters and a full mission report when he does.

Thanks to [Alec Smecher] for the tip.

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Library Makes Arduino To Arduino Serial Communications Dead Simple

May 31, 2011 by 12 Comments

When [Bill Porter] works on a project, he says that he typically writes his own NMEA standard communications protocols to fit the job at hand. While it makes things easy to troubleshoot, he admits that his custom protocols are wasteful of both processor time and bandwidth. Binary communications on the other hand are more efficient, but a bit trickier to manage.

To make things easy for the common user, he wrote a library called EasyTransfer which abstracts packetized serial communications between two Arduino boards. The process is pretty simple – all one has to do is define a data structure on both Arduino boards so that they know what sort of data is coming over the wire, and EasyTransfer handles the rest. This allows users to worry less about communications protocols or transmission errors, and focus on their projects instead.

If you’re working on a project and searching for an easy way to get a pair of Arduinos talking, swing by his site and grab the library. It doesn’t get much easier.

ChipKIT Uno32: First Impressions And Benchmarks

May 27, 2011 by 49 Comments

Following Maker Faire, we’ve had a few days to poke around with Digilent’s 32-bit Arduino-compatible chipKIT boards and compiler. We have some initial performance figures to report, along with impressions of the hardware and software.

Continue reading “ChipKIT Uno32: First Impressions And Benchmarks” →

I2C Arduino GPS Shield

May 24, 2011 by 11 Comments

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[Wayne] wrote in to share an item he just finished working on, an I2C GPS shield for the Arduino. While other GPS solutions have existed for quite some time, his caught our eye due to its feature list.

The shield removes a good bit of the hassle associated with parsing raw NMEA data from traditional GPS addons. While you have the option to communicate with the GPS module over serial in order to obtain the raw data, the use of the I2C interface makes getting the most commonly used GPS data a breeze. The GPS module itself can be set to update at anywhere from 1 to 10 Hz, and [Wayne] says that the I2C bus blows away the oft-used 9600 baud serial interface. While I2C is primarily used for receiving data, it can also be utilized to configure the GPS via its control registers, allowing for on the fly settings tweaks.

While he does sell the units pre-assembled at a competitive price, [Wayne] also provides a full schematic, making this an easy afternoon project once you have sourced the proper components.

Fixing Arduino’s Serial Latency Issues

May 18, 2011 by 42 Comments

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[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.

Data Scraping And Visualization With Python

April 27, 2011 by 8 Comments

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[Greg] built himself a small indicator dial with his laser cutter, and wanted to use it for visualizing server performance and load information. Before he started using it for server monitoring however, he thought he should test out his data parsing skills on a simpler data set.

Pachube has a wealth of information that can be freely used for whatever project you might have in mind, so [Greg] started looking around for something interesting to track. Eventually he located the data feed for a tanker ship and wired his dial to display the ship’s speed. He uses a Python script to interface with the Pachube API, which is fed to his Netduino board. A servo motor then changes the position of the dial based on the feed’s data. Since large tankers don’t change speed often, the experiment was a bit of a letdown. He searched for a bit and tuned into another feed that tracked wind speed in New Zealand, getting much better results.

His future plans include hooking it directly to his network and eventually using it to monitor his servers…at least once the novelty of tracking random data feeds wears off.

All of his code is available on GitHub, and he is happy to make a gauge for anyone who is interested, though he doesn’t currently list a price.