1-Wire HVAC Monitoring System

July 29, 2009 by Steve Watkins 10 Comments

1-wire hvac control

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

pocketerm

[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]

Custom Flex Sensors

July 25, 2009 by Zach Banks 14 Comments

flex

Flex sensors, like the ones used in the Nintendo Power Glove, are generally expensive and hard to find. However, [jiovine] demonstrates that they are easy enough to make from spare parts. He sandwiched a strip of plastic from ESD bags between pieces of copper foil, and wrapped the whole thing in heat shrink tubing. The sensor is able to detect bends in either direction, unlike the original power glove sensors. His version had a nominal resistance of about 20k ohms, but by choosing a different resistive layer you could create sensors that are more or less resistive.

Related: 5-cent tilt sensor

Camera Peltier Cooler

July 23, 2009 by Zach Banks 36 Comments

[Gary Honis] has been modifying his Canon Digital Rebel XSi in order to do astrophotography. He previously removed the IR filter and replaced it with a Baader UV-IR cut filter that lets most infrared light through. However, in order to reduce noise in the pictures, he had to cool the camera down. He based the project on a peltier cooler that he salvaged from a powered beverage cooler. He made a small aluminum box and insulated it with styrofoam to hold the camera body. The peltier cooler was then attached on the side. It takes just over an hour to cool the camera down to 40 degrees, but the shots come out a lot clearer.

[thanks adam]

4D Systems Micro Drive

July 21, 2009 by Steve Watkins 23 Comments

p1193335689

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

ardunio avr isp programming

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.

Homemade Regenerative Tube Radio

July 13, 2009 by Steve Watkins 24 Comments

There are no microcontrollers in this project. In fact you wont find a single transistor. This classic regenerative tube radio, modeled after an early 20th century homebrew is complete with schematic and additional photos. For those who are not familiar with tube designs and for simplicity, the regeneration circuit can be thought of as feedback though this relation may be argued. Read the rest after the break which includes a crash course in tube operation. Continue reading “Homemade Regenerative Tube Radio” →