How to replace a Netgear router antenna

rp-sma-adapter-installed wanted to use a different antenna for their Netgear mbr624gu WiFi router. Unfortunately, this model comes with an antenna that is not removable. As with other antenna retrofits, this involves no soldering. But because there is already a mounting area for an antenna, no case altering is needed either. After opening the router with a Torx driver it was discovered that the non-removable antenna was connected to the board with a mini rf connector (U.FL). The antenna and its mounting bracket were removed and a U.FL to RP-SMA adapter was put in its place using a washer to secure it to the rear plate of the router. Now any external antenna can be used and the router still looks brand new.

8-bit binary calculator


Don’t feel like shelling out $5 for a fancy factory made calculator that won’t even do binary math? [Jeff] decided to prove his mastery of gates and his disdain for base 10 by building a binary calculator using XOR, AND, and OR chips. Calculations can be input in two ways: through digital logic headers or by three banks of DIP switches used to enter the operator and the two operands. Although limited to addition and subtraction, this is a great way to make sure you really understand digital logic. Take a look at the rough design schematics in his album. The design is modular so if you have one of each gate and a few LEDs sitting around you can give this a whirl.

The Blind Juggler

The Blind Juggler is a robot that juggles or bounces balls in a controlled manner without any sensory input. It is basically just a linear actuator with a paddle on the end to smack the ball back into the air as it returns to the ground. The crazy thing is, it is doing this based purely on pre programmed math. There are no sensors telling it to make any adjustments. While we could envision this functioning, we would never have expected it to be as stable as it is. You can see in the video above that they can actually move the entire robot around while maintaining the bounce. Also check out the pendulum version, instead of just actuating vertically, it is mounted as a pendulum allowing the ball to travel back and forth in an arc.

[via BotJunkie]

Router/Twitter/Arduino clock


[Kyle] decided to build the above LED clock for his church. Though it may look impressive enough, it is also hiding loads of features. [Kyle] wanted to make the clock as easy to control as possible, so rather than use buttons or dials to control what is being displayed, he used Twitter. The clock is connected to the internet through a Linksys WRT54GL. The router was hacked so not only does it supply the connection to Twitter, it also parses all of the replies the clock’s feed gets. The clock responds to commands to turn it on or off, run a countdown before service, display the number of viewers on the church’s live stream, and display a sequence of numbers. The time never needs to be set, as it is synched from the internet. The circuit for actually driving the display is based off a PIC, but it was changed to run off an Arduino.

DIY Lincoln welder conversion

[Fritz] built this 600 joule capacitive discharge spot welder in a case scavenged from a Lincoln plasma cutter. All of the circuitry was designed by [Fritz] and the schematics are available on his website. He has a few other welding related project also documented on his site that are worth checking out. While this isn’t the first homemade spot welder we have seen, it is definitely the first one with a case mod. If you are not up to the challenge of building one quite as complex as [Fritz]‘s example, a microwave can be used as the donor appliance in simpler designs.

Zune HD teardown


Our friends over at ifixit are at it again, how they get these devices so early before release and make a complete teardown in time still amazes us. Today they bring us the latest Microsoft media device, the Zune HD. Some features worth mentioning: The astoundingly thin, 1mm we’re talking, OLED screen. The Nvidia Tegra 2600 processor, hinting at 3D game capability. And finally who could forget the 660 mAh battery. But isn’t that 129 mAh less than the iPod touch? Microsoft’s reply, supposedly the Zune HD is using many more low power hardware solutions in this device. Either way, the competition is on, who will be the victor?


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