[Bayres’] dad setup a webcam as a surveillance camera for a remote property. The only problem was that the only stable Internet connection they could get at this property was DSL. This meant that the external IP address of the webcam would change somewhat often; the needed a way to keep track of the external IP address whenever it changed. That’s when [Bayres] built a solution using Arduino and an Ethernet shield.
The main function of this device is to monitor the public IP address and report any changes. This is accomplished by first making a request to checkip.dyndns.org. This website simply reports your current public IP address. [Bayres] uses an Arduino library called Textfinder in order to search through the returned string and identify the IP address.
From there, the program compares this current value to the previous one. If there is any change, the program uses the Sendmail() function to reach out to an SMTP server and send an e-mail alert to [Beyres’] dad. The system also includes a small LCD. The Arduino outputs the current IP address to this display, making it easy to check up on the connection. The LCD is driven by 74HC595 shift register in order to conserve pins on the Arduino.
The system is also designed with a pretty slick setup interface. When it is booted, the user can enter a configuration menu via a Serial terminal. This setup menu allows the user to configure options such as SMTP server, email address, etc. These variables are then edited and can be committed to EEPROM as a more permanent storage solution. Whenever the system is booted, these values are read back out of the EEPROM and returned to their appropriate variables. This means you can reconfigure the device on the fly without having to edit the source code and re-upload.
If you’re not willing to shell out for a reasonably powerful laptop it seems that there’s not a ton that can be done to boost your gaming performance. That is, unless you have an empty Express card slot and the right chipset.
[Phatboy69] recently put together an external video card for his notebook, with fantastic results. His Vaio Z128GG had an Nvidia GT330M graphics card onboard, which is decent but nothing to write home about. Using an Express card to PCIe adapter, he added an external Nvidia GTX580 to his system, and he couldn’t be more pleased with the results. While the card does take a performance hit when connected to his laptop in this way, he claims that his graphics performance has increased ten-fold, which isn’t too shabby.
There are many variables on which this process is heavily dependent, but with the right amount of tweaking, some great laptop gaming performance can be had. That said, it really does take the portability factor of your notebook down to about zero.
If this is something you might be interested in, be sure to check out this thread over at the Notebook Review Forums – it’s where [Phatboy69] found all the information he needed to get his system up and running properly.
Those who are familiar with Atmel’s line of 8-bit AVR microcontrollers should already know that some of them have support for external RAM. But have you ever actually used this feature? We haven’t. Now you can learn how it’s done by reading through this guide. It touches on all of the hardware, but doesn’t dwell on it. Instead, you’ll get the background you need on how to write to, read from, and test an external module like the one sticking up in the image above. The test routine shows how to make sure everything’s working correctly with your memory mapping before you begin developing firmware around this increased capacity.
Microcontroller interrupts are one of the big tools in our embedded programming arsenal. They make the chip listen for particular events, and once detected they stop what they’re doing and run a separate set of code called and Interrupt Service Routine. We’ve come across two fairly new tutorials on the subject that you should check out if you’re not yet a master on the topic. One is a ProtoShack tutorial on ATmega168 external interrupts, and the other is a Newbie’s Guide to AVR Interrupts by [Dean Camera] (we’ve been a fan of his tutorials for some time). Both cover a range of topics from what interrupts are, to avoiding the common problems of volatile data types and the compiler optimization caveats.
What can you do with interrupts? External interrupts can be used to wake up a project like this LED menorah from sleep mode. Interrupts can be used to monitor a timer for a certain value or an overflow for use in generating a pulse-width modulation signal. The TI Launchpad uses an interval timer interrupt for button debouncing in projects like this code which was ported from an AVR chip. The source for both is available if you wanted to compare how the two differ.
Interrupts are powerful. Learn them, love them, use them.
External antennas on netbooks are notorious, from EEE PCs to the Panasonic CF-R1, but this is the first on an Acer Aspire One we’ve seen. [xRazorwirex] sent in his external antenna hack for the 802.11n capable D150, with the intention of increasing performance, but he says he can’t attest to any change. Unfortunately the lock slot had to be removed, but a small price to pay for a big increase in connectivity. The process seems simple enough, and could probably be done within a half an hour. Now that there is an external link why not build a Cantenna, hop in the car, and HeatMap the neighborhood!
[Steven] managed to get his hands on a Panasonic CF-R1 for pretty cheap. Though it is a decently powerful machine, it was built in 2002 and didn’t come with an internal wireless card. It did, however have a mini-PCI slot. [Steven] promptly installed a wireless card, but found the internal antenna lacking. The solution was to custom mount an external antenna. Mounting it was fairly easy, he removed the phone jack and epoxied the connector in its place. The reception was greatly improved. He says he went from seeing 6 access points to 31 as soon as he installed it. Similar things have been done to the Eee PC 900.