Doug Ford, former head designer from Rode Microphones continues with Part 2 of the microphone technology series by explaining the construction of noise cancelling Figure 8, cardioid, and hyper cardioid microphones. Also, how the polar patterns and responses relate to the physical construction, and how the frequency response is affected.
Proximity boost effect,
Microphone calibration is also discussed using a home made artificial voice speaker box.
And practical considerations about foldback wedges used in stage performances and how to avoid feedback using proper microphone technique.
EEVblog #605 – Fig.8 & Cardioid Microphone Patterns - [Link]
An introduction to why and when terminations are needed for transmission lines in both high speed digital applications and RF applications. 50 ohm termination examples are given, but the principles apply for other line impedances as well. The basic operating principles of signal propagation down a transmission line and the effects of reflections coming from improperly terminated are covered. Examples for digital-like signals as well as RF signals are given. A description and examples of what is meant by Standing Waves is also given. As a bonus, the properties of quarter wavelength transmission lines in RF applications is also presented.
Transmission Line Terminations for Digital and RF signals - [Link]
I’ve been looking for ways to control my Service droid robot, my Service droid robot has an ATmega2560 (with Arduino bootloader) and a Raspberry Pi. My goal is to control it over wifi. But I wanted to start with some more simpler things first. I’ve recently found some python code on letsmakerobots.com that lets me sent data over I2C from a Raspberry Pi to a micro controller.
Before getting this to work you need to configure I2C on the Raspberry Pi. Adafruit has written a nice guide how to do this. I also installed the python-SMBus package: sudo apt-get install python-smbus.
Controlling an Arduino through a Rapsberry Pi webserver - [Link]
Bajdi blogged about his Arduino pro mini undershield:
I’ve designed another PCB This time it’s a simple undershield for the Arduino pro mini. I received the PCB’s from Electrodragon (12$ for 10PCB’s) last week. The PCB has a schottky diode and a 5V linear regulator, I’m using an LM2940 5V regulator. For the rest there are just 2 rows of female headers to plug the pro mini in and 3 rows of male pins on each side.
The reason I’ve had this PCB made is that pro mini’s are dirt cheap these days, you can find them on Ebay or Chinese shops for mess then 4$. That makes them the cheapest Arduino on the internet. It’s cheaper and easier to buy a pro mini and integrate it in to your own project then to design your own PCB with an ATmega328.
Arduino pro mini undershield - [Link]
TakeItApart.com is a new website where you post your photos of disassembly guides. See how to take apart everyday things, and find things to do once inside. So simple, check it out!
TakeItApart.com – Your source for disassembly information - [Link]
By European Editors:
Military and aerospace, where rugged operation and reliable performance in a confined, hostile environment are paramount, have long been the most dominant markets for thermoelectric energy harvesting. Typically, thermoelectric devices exploit heat from engines and motors and use it to power sensors and wireless sensor networks for condition monitoring applications. Recent innovations are generating growth in this sector, as well as in allied sectors.
This article will review some of the major avionics and aerospace applications that use thermoelectric devices. For example, commercial and military aircraft incorporate sensors and sensor networks powered by thermoelectric generators to monitor the aircraft skin for damage that can cause stresses and structural weakness. In the aerospace sector, the Mars Rover, Curiosity, Galileo satellites, New Horizons space probes, and Cassini spacecraft are all TEG users.
Typical devices that will be considered include the CP range of TEGs from CUI, and the eTEC modules from Laird Technologies. Further consideration will be given to the management of energy generated by TEGs, with reference to the LTC3108 DC/DC converter from Linear Technology.
Thermoelectric Energy Generation Takes Flight for Aircraft and Spacecraft Monitoring - [Link]
Toshiba Corporation today announced that it has developed the world’s first 15-nanometer (nm) process technology, which will apply to 2-bit-per-cell 128-gigabit (16 gigabytes) NAND flash memories. Mass production with the new technology will start at the end of April at Fab 5 Yokkaichi Operations, Toshiba’s NAND flash fabrication facility (fab), replacing second generation 19 nm process technology, Toshiba’s previous flagship process. The second stage of Fab 5 is currently under construction, and the new technology will also be deployed there.
Toshiba starts mass production of world’s first 15nm NAND flash memories - [Link]
By Tessel Renzenbrink:
David Hunt built himself a working mobile phone using a Raspberry Pi and off-the-shelf components. The main building parts are the $35 Adafruit Touchscreen interface and a $48 SIM900 GSM/GPRS module for making phone calls. In total the phone costs $158 to build.
PiPhone: Turning Your Pi into a Phone - [Link]
The controller, host and application with integrated (field programmable) Flash memory is contained in a 6 mm x 6 mm chip. The GPIOs support both analog and digital signals. TI anticipates the chip will be useful in the field of:
- Keyless entry using a Bluetooth Smart Ready smartphone or Bluetooth Smart key fob, either standalone or in conjunction with TI’s car access solutions
- Lighting controls to deliver ambient, clustered and programmable LED lighting
- Diagnostic information to help users understand engine warning lights
- Services with iBeacon technology for fast discovery and easy pairing with in-car Bluetooth Smart technology
A Chip to Link your Smartphone and Automobile - [Link]
ASCAS @ instructables.com writes:
Control your Arduino with voice commands using an Android smartphone! Before we make a voice activated home automation system, we must first learn the basic principles of the experiment. This guide will let you command the Arduino using your Android smartphone and a HC-05 Bluetooth module.
The designer of the app did not include a sample code. I looked for alternatives in Google’s PlayStore but none was as good as the app that I’ve found. Luckily, I was able to figure it out although it took me a while to program it. Sorry IOS users, this app isn’t available in Apple’s app store :/
Voice Activated Arduino (Bluetooth + Android) - [Link]