Laptop To All-in-one PC Conversion

September 4, 2013 by Marsh 10 Comments

laptop2allinone

You probably have an old laptop shoved into a far, dark corner of your closet, gathering dust as it sits there alone and unwanted. Show it some love like [Oakkar7] and hack it into a desktop all-in-one PC. He had his work cut out for him, though: dead motherboard, busted case, worthless battery. [Oakkar7] starts by taking the case apart and removing the LCD screen. He removes the motherboard to discover two toasted capacitors in need of replacement. A short solder job later and the computer springs to life.

[Oakkar7] needs the LCD to face outwards while sitting against the rest of the laptop. The connecting cable doesn’t reach, so he carefully removes it, and flips it around to get the extra length needed. The final step is to fashion some aluminum support bars that attach to the bottom of the case, which mount onto another aluminum stand holding everything upright. At this point [Oakkar7] has tossed the battery, the keyboard, both the CD and floppy drive (yes it’s that old), and moved the speakers into the battery’s former home. For the finishing touch, a USB hub provides connections for the new keyboard, mouse and a Wifi dongle.

[Oakkar7] shared his project with us after reading [Elad’s] ground control station laptop conversion. Maybe these two projects can convince you to save a neglected laptop.

A Weekend Trip To Verify General Relativity

September 3, 2013 by Mathieu Stephan 77 Comments

8 years ago, for the 100th anniversary of the theory of relativity [Tom] decided to test the general theory of relativity.

As he was going to Mt Rainier (5400ft high) with his children for the weekend, he brought in his van 3 cesium clocks while leaving other atomic clocks at his home for comparison. The theory behind the test is that if you’re are at higher altitudes, then your speed (in a galactic coordinate system) is higher than the one you’d have at sea level and therefore time would go “slower” than at lower altitudes.

[Tom] brought 400 pounds of batteries, 200 pounds of clocks and left his car turned on during his 2 days stay in the ‘Paradise Lodge’. He used 120V DC to AC converters and chose to bring 3 cesium clocks to have a triple redundant setup. When he came back home, he had the good surprise of finding a time difference of 23ns. This is a great application for those rubidium sources you’ve been scavenging.

[Thanks Indyaner via Reddit]

A Real Car Remote Controlled With An Arduino… What Could Go Wrong?

September 1, 2013 by Mathieu Stephan 39 Comments

[Gilad] tipped us about his latest project, where he adds plenty of pneumatics and electronics into his wife’s car to remote control it.

The brake/throttle pedals are actuated by pistons controlled by electronic valves, and a standard DC motor is in charge of turning the wheel. The Arduino code tells us that the valves will be opened as long as the remote up/down channel is above/under given values. The frame is based on Festo aluminium profiles and we’re not sure where the mains used for the DC/DC converters is coming from. As the valves use 24V and the motor 12V, standard N-Mosfets and power relays are used for voltage conversion. The remote controller [Gilard] used is actually 20 years old, so the output signal of the receiver isn’t actually really clean.

We do hope to never see this car on the road….

Tearing An Old Laptop Apart To Build A Ground Control Station

August 31, 2013 by Mathieu Stephan 53 Comments

Being tired of assembling and disassembling parts/cables every time he went outside to fly his plane, [Elad] figured that he’d be better off building his own ground control station.

The core of the station is based on an old laptop with a broken screen he had laying around and (luckily) an older laptop screen he had found. As the latter only accepted LVDS, an adapter that could generate theses signals from the standard laptop’s VGA output was needed. [Elad] therefore disassembled his laptop and fit all the parts in a Pelican case he bought, as well as a lead-acid battery, a 12V to 19V stepup converter (to power the laptop), temperature/voltage/current sensors with their displays, 40mm fans, an AC/DC converter to charge the battery and finally a pico-UPS to allow uninterrupted use of the station when switching between power sources.

Because [Elad] didn’t have access to any machinery, PVC foam was used to maintain all the parts in place. Autonomy of his station is around 2.5hours on a single 12V 7Ah battery.

Disabling Under/over Voltage Protection On ATX Power Supplies

August 30, 2013 by Brian Benchoff 63 Comments

voltage

[C] just recently put together a RepRap. Not wanting to spend the money on a dedicated power supply, he looked around for a cheaper solution and found one in an off-the-shelf ATX computer power supply. These ATX supplies are actually a little finicky when not used in a computer, as [C] found, with voltage drops on the +12 line even when a load is connected to the supply. Undeterred, [C] eventually solved this problem by cutting some traces and grounding a few pins on the protection circuit.

The ATX supply [C] used could supply 25 amps on the 12 volt rail, more than enough for a simple RepRap. There was only one problem: the supply would randomly shut itself off, ruining the print. After a little googling, [C] found some people powering 12 volt amplifiers that were running into the same problem. Their solution was to ground a few pins on the protection circuit. Their supply wasn’t quite like [C]’s so he had to do a little experimentations.

It took a few iterations to get right, but [C] managed to figure out exactly which pins on the “power supply supervisor” IC must be grounded to disable the undervoltage protection. With these pins grounded, the protection circuit of the supply is completely disabled, giving him and uninterrupted 25 amps at 12 volts. If you’re looking for a cheap source of power, it would be hard to go wrong with [C]’s tutorial and his power supply of choice.

Open Activity Tracker Webcast

August 28, 2013 by Eric Evenchick 2 Comments

The Upverter team loves their FitBit activity tracking devices, but wanted access to raw data. They decided to build their own Open Activity Tracker that would pump data onto an SD card or to a Bluetooth device for processing.

The device uses MPU-9150 motion tracking IC to gather information on movement. This chip combines an accelerometer, gyro, and compass. It also does on-board processing, providing useful data to your host processor over I2C. The only bad news is that it’s a LGA package, which aren’t fun to solder by hand.

The design also has a SD card, Bluetooth module, pressure sensor, and e-ink display. These are all connected to a low power ARM microcontroller.

The team has been webcasting their design sessions, and tonight [Eric Evenchick] (that’s me) will be joining them as they try to cram all of these components onto a PCB. You can watch the live webcast starting at 8:30pm Eastern.

You can watch the previous design sessions after the break.

Continue reading “Open Activity Tracker Webcast” →

Building A ‘high-end’ USB Audio DAC

August 27, 2013 by Mathieu Stephan 63 Comments

As [Jan-Erik] had already built a simple USB connected Digital-to-Analog Converter (DAC), he decided to make the high-end version of it.

The prototype you see in the picture above is based on:

the PCM2707C from Texas Instruments which takes care of the USB communication and outputs I2S audio data
the PCM1794A, a 132dB SNR 24-bit 192kHz DAC which receives I2S protocol
the OPA4134, a high performance audio operational amplifier

The on-board +3.3V and -5V voltages are generated by inductor-less power supplies. As [Jan-Erik] mentions in his write-up, the ‘high-end’ was put between single quotes because the PCB is single sided and uses through hole passive components. The board was designed using Kicad, etched by himself and put in a machined enclosure. All the production files can be downloaded from his website so you may produce it within a day.