Wireless unread email counter tells you how busy you’re not

counter

One of the marks of how busy you are – or how well your spam filters are set up – is how many unread emails you have in your inbox. [trumpkin] over on Instructables posted a great tutorial for making a wireless counter that displays the number of unread emails in your Gmail account.

[trumpkin] used a tiny and inexpensive 419 MHz transmitter and receiver combo to make this project work. On his desktop, he wired up a USB to UART bridge attached to the transmitter. For the receiver side, an ATMega328 reads the data coming off the receiver and displays the number of unread emails on two seven-segment displays.

The wireless device runs off of two AA batteries and should provide enough power to keep the email monitor running for a long time. More than enough time for your inbox to fill up and for you to become overwhelmed with the work you should be doing.

TP-Link router turned into a DALI automated lighting controller

dali-control-in-tplink-router

The members of Shackspace continue to put up impressive hacks based around the tiny TP-Link routers. This time around [Timm] has shoehorned a DALI controller inside the router case. This is a protocol we don’t remember hearing about before. The Digital Addressable Lighting Interface is a control network for commercial lighting. That way people responsible for taking care of large buildings can shut off all the lights at night (to name just one use). The new room at Shackspace has this style of controllers in its lights.

The two brown wires coming into the router make up the data bus for the DALI system. It connects to the add-on PCB which uses an Atmel AT90PWM316 microcontroller. The chip is specifically designed for DALI networks which made the rest of the project quite easy. It talks to the lights, the router talks to it, bob’s your uncle, and you’ve got network controlled lighting. Get this in a big enough building and you can play some Tetris.

In case you were wondering. Yes, this project has already been added to their TP-Link firmware generator.

RPi control your server PSU over the Internet

remote-server-psu-control-via-RPi

Here’s an interesting use of a Raspberry Pi to control the PSU on a server. [Martin Peres] is going to be away for a few months and still wants access to his PC. This isn’t really all that tough… it’s what SSH is made for. But he also wants lower-level access to the hardware. Specifically he needs to control and get feedback on what the PSU is doing, and even wanted to have access to the serial console without having to go through the computer’s NIC.

The image above shows one part of his solution. This is a custom Ethernet port that connects to his Rasberry Pi header breakout board. Inside the computer the jack is wired to the motherboard power LED to give feedback about the current state of the power supply. It also patches into the green wire on the PSU, which lets him turn on the power by pulling it to ground. After working out the cable routing he developed a web interface that makes it easy to interact with the setup.

As with other hacks along these lines letting an embedded computer run 24/7 is a lot less wasteful than leaving a PC on. That’s a concept we can really get behind.

[Read more...]

33 Node Beowulf Cluster built with Raspberry Pi

rpi-beowulf-cluster

Not only did [Josh Kiepert] build a 33 Node Beowulf Cluster, but he made sure it looks impressive even if you don’t know what it is. That’s thanks to the power distribution PCBs he designed and etched. In addition to injecting power through each of the RPi GPIO headers they host an RGB LED which is illuminated in blue in the images above.

Quite some time ago we saw a 64-node RPi cluster. That one used LEGO pieces as a rack system to hold all of the boards. But [Josh] used stand-offs to create the columns of hardware which are suspended between top and bottom plates made out of acrylic. The only thing that’s unique about each board is the SD card and that’s why each has a label on it that identifies the node. These have been flashed with almost identical images; the host name and IP address are the only thing that changes from one to the next. They’ve been put in order physically so that you can quickly find your way through the rack. But functionally this doesn’t matter… put the card in any RPi and it will automatically identify itself on the network no matter where it’s located in the rack.

Don’t miss the demo video where [Josh] explains the entire setup.

[Read more...]

Hacking VM for peak performance

vm-tweaking

[Cyber Explorer] recently ditched his collection of physical computers acting as servers by virtualizing the lot of them. But with every change there’s a drawback. Although it wasn’t too hard for him to set up the virtual machines, he did end up spending quite a bit of time trying to improve the bandwidth. Luckily he posted an article chronicling all of the VM tweaks he used to improve the system.

The experience involves both a Windows 8 machine, as well as a some Linux boxes meaning there’s something here for everybody. At each step in the process he performs some throughput tests to see how the boxes are performing. Tweaks are numerous, but include trying out different Ethernet drivers, making sure all modules are up to date, squashing at least one bug, and giving jumbo-frames a try.

[Thanks Omri]

Self-waking computer for DIY cloud storage

self-waking-cloud-storage

[Dominic] decided to take control of his cloud storage by switching to OwnCloud. Unlike most cloud storage solutions, this isn’t a company offering you free space. It’s an open source software package which your run on your own machine. [Dom] didn’t want to leave his box running 24/7 as it would be unused the majority of the time. So he hacked this router to switch on the computer whenever he tries to access the storage.

Obviously this is a Wake-On-Lan type of situation, but the hardware he has chosen to use doesn’t include those features. Since he already had this TP-Link 703n on hand he decided to use it as a controller for the computer. His method is quite clever. The router is running a script that monitors the computer and the bandwidth it’s using. When traffic from the network stops, the router will issue a shutdown command within just a few minutes. It then assigns itself the computer’s IP address so that it can listen for incoming requests and use the relay on that breadboard to turn the box back on. Obviously running the embedded system is much more efficient than having an entire computer turned on all the time, and it’s WiFi capabilities mean no cords to run to the home network.

UDP between STM32-F4 Discovery boards

stm32-f4-udp

[The Backwoods Engineer] tested out a new accessory kit for the STM32-F4 Discovery board. The image above shows two boards communicating with the UDP protocol. Notice the extra PCB into which each Discovery board has been plugged. This is a third-party add-on which adds Ethernet, RS-232, SD card slot, and a connector for LCD or Camera. We’ve had one of these F4 Discovery boards on hand for a while and haven’t figured out a good way to connect external hardware to the huge dual pin-headers. This doesn’t solve the problem — the base board also includes dual headers to break-out all the pins — but having Ethernet, serial, and SD certainly reduces the need to add all that much more. The other drawback to the hardware is that the sample firmware is targeted at the IAR Embedded Workbench which is neither free, nor in the realm of affordable for hobbyists.

The NIC used on the baseboard has auto-crossover capabilities so the boards were connected using a regular Cat6 patch cable. This example has the boards constantly sending UDP packets with the module on the right reporting status information to a terminal via the serial connection.