This video gives you the basics of how to calculate and use a simple resistive current shunt with an analog panel meter to change the current that is needed for a full scale deflection. The notes page for this video can be found here.
Using a Current Shunt with a Panel Meter / Ammeter scale change – [Link]
electronictechnician.wordpress.com has published a library for use SD cards in SPI completely written in C.
It’s a library for use SD cards in SPI mode with uControllers, entirely written in C. This library can work with SD cards and also has the possibility to emulate the behavior in a PC file (GNU/Linux) using the macro _M_IX86. It’s for debugging purposes. The data transfer is oriented to 512 byte size, remember this.
ulibSD – a library for use SD cards in SPI mode with uControllers – [Link]
moamindustries.com hacked an Omron RS8 blood pressure cuff by adding a UART interface to it.
As part of a prototype developed 12 months ago I was tasked with reading measurements from a blood pressure cuff [sphygmomanometer] in real time. Not surprisingly there are no consumer level devices that have a serial interface because what ‘normal’ person would want such a thing!
Initially we considered our own interface for a blood pressure cuff. Just run the pump and take the readings with our own processor and pressure sensor, how hard can it be.
Hacking a UART on a blood pressure cuff – [Link]
WISP, the Wireless Identification and Sensing Platform, is a family of sensors that are powered and read by UHF RFID readers.
WISP, the Wireless Identification and Sensing Platform, is a family of sensors that are powered and read by UHF RFID readers. WISPs do not require batteries since they harvest their power from the RF signal generated by the reader. The WISP is an open source, open architecture EPC Class 1 Generation 2 RFID tag that includes a fully programmable 16 bit microcontroller, as well as arbitrary sensors.
WISP – Wireless Identification and Sensing Platform – [Link]
Bob hacked a home weather station transmitter and made a home thermometer from it. He writes:
Recently I’ve found this piece of electronic on the dumpster, it was looking interesting – compact case with battery holder, LCD display, temperature and humidity sensor. It has also radio transmitter, but I’m not interested in it since I don’t have the receiver station. I decided to bring it back to life.
Hacking home weather station transmitter – [Link]
Tiny stereo audio amplifier board has been designed around SMD TDA7266D IC from ST. The TDA7266D is a dual bridge amplifier specially designed for Portable Audio, LCD TV/Monitor, PC Motherboard, and TV applications. This circuit provides high quality audio output of 3W approx. on each channel with standard audio signal input. The circuit works with 3.5V to 5V. Due to low supply input this amplifier is suitable for small size audio gadgets and portable audio applications like MP3 player, Voice messaging system, Warning signals, Annunciator etc.
- Supply voltage range 3.5 to 5v (maximum supply 5v due to small pcb and small thermal area)
- Output power 3+3w @thd = 10%, rl = 8ω, vcc = 3.7v (3w approx.)
- Single supply
- Minimum external components no svr capacitor no bootstrap no boucherot cells internally fixed gain
- Mute functions (jumper close)
- Short circuit protection
- Thermal overload protection
3W Stereo Audio Amplifier using TDA7266D – [Link]
In this article “Rui Santos” shows us how to configure Raspberry Pi as server and use it to toggle two LEDs over the internet.
In this project you’ll create a standalone web server with a Raspberry Pi that can toggle two LEDs. You can replace those LEDs with any output (like a relay or a transistor). In order to create the web server you will be using a Python microframework called Flask.
Raspberry Pi Web Server using Flask to Control GPIOs – [Link]
Clemens Valens @ elektormagazine.com shows us a new IC Package that keeps the IC cool.
Texas Instruments’ HotRod QFN is a thermally enhanced plastic package with solder lands on all sides as well as power buses for enhanced current carrying capability. Inside the package the die is mounted on a copper lead frame which eliminates the power wire bonds, improving electrical and thermal performance. This technique also improves application efficiency and minimizes package parasitic radiation.
Hot rods keep the die cool – [Link]
Torex Semiconductor’s XC9141/XC9142 series of 0.8A step-up DC/DC converters come with an input–output disconnection function (load disconnection function) to prevent malfunctioning during standby, and for device functionality that enables power supply to RTC.
When the output voltage is 3.3V, the IC can start from an input voltage of 0.9V with a resistance load of 100Ω, enabling use in devices driven by one alkaline or nickel-hydrogen battery. The input voltage range is 0.65V to 6.0V, and the output voltage range can be set from 1.8V to 5.5V (accuracy ±2.0%) in steps of 0.1V. A switching frequency of 1.2MHz or 3.0MHz can be selected to match the application.
0.8A step-up DC/DC converters in a tiny package – [Link]