BPSK On 433 MHz European ISM Band

August 3, 2009 by Steve Watkins 10 Comments

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[WaveRider] is using a type of phase shift keying called BPSK to transmit digital sound and video for remote telemetry. Though a higher signal to noise ratio (SNR) is generally sought after with communications, legal limitations are imposed on total radiated power. To balance the two headed beast, he opted out on frequency shift keying due to binary shift keying’s ability to work with lower SNR. This adds the difficulty of properly reconstructing the digital signal at the receiver. A PLL based carrier regeneration circuit is used to reconstruct the signal. Using the Rabit2000 processor as the host controller on both transmitter and receiver, 96KB/Sec serial data is obtained. On the other side of the spectrum is the Homemade regenerative tube radio.

1-Wire HVAC Monitoring System

July 29, 2009 by Steve Watkins 10 Comments

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The 1-Wire HVAC monitoring system is for residential Geothermal HVAC systems. This project utilizes the so called 1-wire temperature sensor. A single board computer handles the brunt of the work including web accessible trend data. With access to the underling temperatures, the over all system performance may be gauged. Earlier this year we covered a HVAC web enabled monitor that adds an element of control. As the industry adopts modern control architectures, we hope to see more HVAC hacks around.

Propeller-based Terminal

July 25, 2009 by Zach Banks 15 Comments

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[Vince Briel] has created an embedded device based on the Parallax Propeller chip that acts as a serial terminal. It takes input from a standard PS/2 keyboard and outputs color VGA. It also has a second serial port to connect to a PC for debugging or programming. He is selling kits and has the schematics available. The board has a lot of hacking potential and it could easily be made into a video game or a Wikipedia browser.

[via RetroThing]

Greenhouse Guard

July 24, 2009 by Zach Banks 15 Comments

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[Seth King] sent in his latest hack where he used an Arduino to regulate various aspects of a greenhouse. He has sensors for soil and air temperature as well as light and moisture. He built a custom circuit that uses relays to power fans, lights, and heaters. Using timers and the sensor data, the devices can be triggered to create the perfect environment for sprouts. He hopes to make the whole thing wireless by integrating XBees, but for now he ran a USB cord to his computer.

Related: Automatic grow light

4D Systems Micro Drive

July 21, 2009 by Steve Watkins 23 Comments

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4D Systems micro drive provides both raw and FAT level access to microSD cards. The module contains a dedicated host controller that transforms what may be an otherwise intimidating card spec into a group of simple serial commands. With a wide supply range of 3.6-5.5 and .1″ lead spacing, this should be cake walk to tinker with. The device doesn’t support FAT32 yet. According to the GOLDELOX-DOS command set page 9, “FAT32 is currently not supported, if you mount a FAT32 formatted disk, you will not be able to access it at all, both FAT and RAW commands will fail”. At the moment the device seems limited at 2GB FAT16 partitions. This sure does seem like cheating after implementing SPI and Nibble mode SD card protocols.

[via Electronics-Lab.Com thanks mozzwald]

AVR ISP Programming Via Arduino

July 15, 2009 by Steve Watkins 32 Comments

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We found this Arduino AVR ISP programmer particularly interesting. AVR microcontrollers can utilize an interface called In-System-Programming. ISP allows the chip to be programmed or reprogrammed while in an actual circuit via a pin header. Atmel’s solution is the AVR ISP MKII programing tool. The MKII can also be reprogrammed just as an AVR. The difference here is that most people are not likely to modify the MKII to be used as anything but a programmer. On the other hand if you already have the Arduino, fetch the avr.isp.03 firmware and AVRdude. Then program a device, for example an ATtiny13 using the Ardunio as the programmer. All the project information is provided under the CC BY-NC-SA 3.0 license. On a related note we covered a Microcontroller cheat sheet which covers AVR devices and ISP pinouts.

Hacking An IButton

July 9, 2009 by Zach Banks 36 Comments

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Maxim’s iButtons, which are small ICs in button-sized disks, are starting to show up in more and more places. They have a range of uses, from temperature loggers to identification, and all use the 1-wire protocol to communicate. Over a furrtek, they hacked an iButton used for buying things from vending machines and created an infinite money cheat. They built a small rig based on the ATmega8 to read and write data to the chip. The data was encrypted, so it wasn’t feasible to put an arbitrary amount on the card. Instead, they used a similar technique to the Boston subway hack and restored a previous state to the iButton after something was bought. They also created a hand-held device to backup and restore the contents of a button for portable hacking.

[Thanks furrtek]