Davide Gironi‘s ambient quality monitor uses Arduino and a bunch of sensors to monitor four indoor environmental parameters, namely temperature, humidity, noise and illumination. The measurements are recorded on to the xively.com platform, as well as displayed locally to the user through 4 bi-color led indicators.
Indoor ambient quality monitor
Antenna analyzers are a common tool used for troubleshooting antennas and fine tuning them for optimal performance. They might cost anywhere from a couple hundreds dollars to thousands based on quality, features, and frequency range of operation. For a low frequency application (< 30MHz), this Arduino-based DIY Antenna Analyzer can be build under $40. The key component of this design is the AD9850 DDS module that can be bought on eBay for less than $5.
DIY antenna analyzer
The following video shows the demo of this project.
via [Hackaday]
This PIC18F25K20-based clock uses radio receivers to synchronize the time with that from the GPS satellites or the DCF77 transmitter, both of which are referenced to atomic clocks.
Very accurate clock referenced to an atomic clock
This project is a clock with radio receivers which can receive the exact date and time from the DCF77 time signal transmitter or the UTC from the GPS satellites and display it on a 128×64 pixel graphic display. DCF77 transmitter and GPS is synchronized to an atomic clock. So basically this project can “connect to” an atomic clock.
This project is an open design: open hardware and open source software.
Solar Power System Controller
The solar energy generator has a buck boost topology DC-DC converter that can either step up or step down the output voltage from the input voltage, which allows the system to operate at the panels peak efficiency known as the maximum power point. The maximum power point is tracked using a current and voltage sensor by periodically changing the input to output voltage relationship of the DC-DC converter and measuring the corresponding changes in output power the sensors. In addition to implementing Maximum Power Point Tracking, the buck boost topology allows the battery operating voltage range to be either higher, lower, or both relative to the panel input voltage depending on the solar panels used. When configured properly it can be used to harness the energy of panels up to 500W in capacity. Batteries capacities can be anywhere from 100 watt hours to a few kilo-watt hours in capacity, and the initial target battery chemistry is lithium iron phosphate due to its high cycle life and increased safety over traditional lithium cells. Other chemistries such as lead acid will also be supported in the future. The generator is composed of the following circuit blocks: a two phase buck boost DC-DC converter, a battery current sensor, a load current sensor, a battery voltage sensor, gate drivers for the converter, a C2000 micro controller, 12V, 5V, 3.3V and 1.8V rails, and a load switch.
Walltech Smartwatch is a bluetooth 4.0 enabled fitness-tracking smart watch designed by John Wall for Android+iOS with a 1.5″ color OLED display, SD card, NFC, wireless charging, and precision IMU.
Walltech Smartwatch
You may have seen any of the smart watches on the market today and thought, “that’s way too expensive,” or “I wish this feature was customizable,” or “darn, I need an android phone for that.” If so, look no further! Sporting a beautiful 1.5″ full color OLED display with micro SD card slot, QI charging, NFC, altimeter, thermometer, compass, gyroscope, accelerometer, pedometer, and full Android/iOS bluetooth 4.0 low energy capability for receiving phone notifications, my Arduino compatible smart watch does it all. Ever wanted a smart watch that you could customize to the core? Use with Android and iOS? Build yourself? Trust is fully open source? My name is John Wall, I’m 16 years old, and from the experience I’ve gained building my previous generation OLED watch, I have set out on an engineering journey, determined to build my own smart watch, the best smart watch.