Moving a resistor for EvalBot power when programming

[Riley Porter] posted a picture of his EvalBot USB power hack. In the photo above we’ve put a box around D6 and D7. The development board ships with a 0 Ohm resistor in the D7 location, patching in power from the USB-B connector labeled USB DEVICE. He found that by moving that resistor to D6 he can power the board from the USB-B connector labeled ICDI.

That connector is the In-Circuit Debug Interface. TI sent us an EvalBot bundle so we pulled it out and tried it ourselves. If you plug in the ICDI it doesn’t power the board, and no USB devices register. Shorting the D6 pads changes this and the following USB device registers:

Bus 002 Device 062: ID 0403:bcd9 Future Technology Devices International, Ltd Stellaris Evaluation Board

So it looks like you need to have two USB connections or be using batteries in order to program the board via USB. The uC/OS-III hardcover book that ships with the EvalBot bundle includes board schematics. We took a look and were surprised to see that they show diodes installed on both pads. Rev A of the online schematics have been corrected, showing an omitted diode on D6 and the 0 Ohm resistor on D7. Images of both schematics are included after the break.

It would have been nice to see a selector switch installed here to give you a little more flexibility when prototyping.

[Read more...]

Apple Studio Display connector ports

[Warrior_Rocker] pulled off his own Apple Studio Display hack by removing the cable and adding ports. As we saw in Wednesday’s post, these displays use a cable with a proprietary connector that combines DVI, USB and Power. Instead of altering the cable, [Warrior_Rocker] removed it completely. By wiring up a standard barrel jack for power, a USB type-B socket, and a DVI port, he can now use standard video, power, and USB cables to connect to the monitor.

This project was actually submitted to us on May 25th and we missed it. It’s sad that sometimes tips fall through the cracks, and we’re sorry that we missed this particularly well-executed hack. [Warrior_Rocker] wrote in asking why his project didn’t qualify after seeing the similar post on Wednesday. So please don’t take it personally if your project doesn’t get posted. If you think it fits right in here at Hackaday and haven’t heard anything after two weeks or so, consider sending to us again.

PIC programmable power supply

This programmable power supply is the perfect addition to your bench tools. [Debraj Deb], who previously built a whole house power monitor, designed this build around a PIC 18F4520 microcontroller. The desired voltage is set with an attached keypad, resulting in a digital output on the 8-bits of port D. The port connects to another protoboard with an R-2R digital-to-analog converter resulting in the target voltage. A set of transistors amplifies the current and a power transistor then takes care of the final output. After the break you’ll find two videos, the first walks us through the hardware and the second demonstrates the device in action, along with measurements of its performance. This certainly provides a lot more functionality than an ATX power-supply conversion.

Update: A big thanks to [Debraj] who sent us a code package as well as the schematic (PDF) used during testing. We’re having trouble getting the code package up for download right now. Check back later, hopefully we’ll have it up soon.

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Whole house current monitoring

[Debraj Deb] put together a current monitoring device that interfaces with the circuit box at his house. The system is controlled by a PIC 18F4520 and uses an LM358 Op-Amp to rectify the AC signal, as well as an MCP6S21 for range adjustments for detecting both high or low current loads. The data displayed on a character LCD includes average, RMS, and peak current. For now the data is saved to an EEPROM and can be dumped using a serial connection but [Debraj] plans to add a GSM modem so he can send energy use data to his cell phone.

[Thanks Ganesh]

SPRIME controlled AC outlets

Reader [Tim Upthegrove] sent in a novel take on powering and monitoring AC outlets and devices called SPRIME, or Simple Powerline Remote Interactive Monitor and Enforcer. Compared to previous hacks, such as 120v switching or Quick cheap remote outlets, that only turned an outlet on or off; SPRIME allows not only control over outlets via the internet, but also power usage of devices currently plugged in.

We really liked their idea of giving power companies access to SPRIME outlets to reduce power consumption during peak hours, but sadly we don’t see it being implemented in homes any time soon. Catch a video of SPRIME after the rift.

[Thanks Chris McClanahan and Jeff Starker for the project, and deyjavont for pointing out our silly mistakes]

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How-to: Make a Mains Crossover Cable

Update: This How-To was written for April Fools’ Day. It is not advised  you attempt to make or even use this cable. The comments have made it very clear how dangerous to you and others using this cable can be. The image above is not of a full male-to-male cable, only the ground is connected, and the generator is not running.

We all know Ethernet has the crossover cable, cars have jumper cables, and RS232 has the null modem. Well, it is about time our wall sockets get their own crossover cable. This crossover cable is great for running power to a circuit disconnected from power. Maybe you are out of fuses, the breaker is broken or you just don’t want to go check the fuse box when there is a murderer about. This cable makes a great gift for even the most loathsome of acquaintances. [Read more...]

Homebrew MagSafe

[Freeload] sent us his custom MagSafe adapter build for laptops. MagSafe for those unaware is Apples (patented) power adapters that prevent damage to laptops when the cord is accidentally yanked from the socket. While we’ve seen some custom versions before of MagSafes they were usually bulky, ugly, and used a ton of unremovable glue. We really like [Freeload's] because its quick, good looking, and the best part – completely removable without marks or damage. In short, an easy weekend project that could one day save your laptop.

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