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13 Jan 2015


by Samir Borle & Peter Li :

For our final project, we have decided to use the microcontroller provided to make a device which would measure body fat percentage of one’s body. The basic principle behind this project is known as bioelectrical impedance analysis. This technique uses a small alternating current flowing between two electrodes attached to skin surface to determine impedance. By determining the opposition to the electric current through body tissues, we can estimate the water content of the human body and use it to estimate fat-free body mass. The IV response characteristics of these tissues can provide a good estimation of percentage body fat.

Bioelectrical Body Fat Analyzer - [Link]

13 Jan 2015


Limpkin wrote this blog article about his tiny NFC Reader with a TRF7970A build, and he will be giving a few of them away:

The main components are:
– the USB-enabled ATMega32U4
– a connector for the NRF24L01
– a Lithium-Ion battery charger
– an NFC transceiver
– a proximity sensor
The main idea of this platform is to read NFC tags while keeping its power consumption low. The microcontroller is communicating with the NFC transceiver so you can use the platform as a standalone device or computer peripheral.
You could therefore control a switch (using the expansion header), send the tag data via RF (using a NRF24L01 you’d connect) or simply have the ATMega32U4 forward the read/write commands sent from your computer. The original idea was to support libnfc.

Tiny NFC reader with a TRF7970A - [Link]

12 Jan 2015


by elektor.com:

At a presentation at the CES in Las Vegas this week, Intel’s CEO Brian Krzanich, showcased their new wearable Curie module. This comes a year after their Edison development system for wearable devices was given its first airing at CES 2014. Intel does not expect the Curie to be available until the second half of 2015 so technical details of the system are a little sketchy. What we can say is that this preliminary version of the Curie is a whole lot smaller than the present day Edison (which was originally intended to be the size of an SD card but grew a few millimetres by the time it reached production).

The Intel Curie Wearable - [Link]

9 Jan 2015


by othermachine @ instructables.com:

Hello! Welcome to another Other Machine project tutorial! I’m Sam DeRose, a former Other Machine Co. Summer Intern. I created The Nerd Watch last summer while working at OMC.

The Nerd Watch displays the time in binary when the button is pushed. The watch shows the hour and minutes by flashing two LEDs in sequence to represent two 4-bit binary numbers (in big-endian format). Here’s a great description of how to read binary numbers.

In this Instructable, I’ll show you how to build a Nerd Watch from scratch with a few electronics components, and an OMC Othermill.

This Instructable presumes you have previous experience working with surface mount electronic components, and that you are no stranger to a multimeter or soldering.

The Nerd Watch - [Link]

9 Jan 2015


by Dmitry Griberg @ dmitry.gr:

You’ve probably seen various holiday or birthday cards that play a little jingle via beeps when they are opened. Last few years have brought new ones that play actual sampled music for a dozen seconds or so. I decided, for this new year’s celebration, to make a card that, when opened, will play a complete song in full fidelity. And the song it should play should be selected randomly each time of many. The project would be housed in a normal CD jewel case. The project was further complicated by the fact that it is impossible to predict shipping times during the holidays. Thus the task was to do all this, using nothing but whatever materials and components that I already had at home. I managed to do this successfully, and the project worked well. It is not the best designed or the most efficient, but it does work.

Musical holiday card using microSD card - [Link]

9 Jan 2015


by Scargill @ scargill.wordpress.com:

This article describes the ESP-01, fitted with LUA firmware that is able to converse with a serial terminal in a high level language, store programs and data, turn things on and off in a package that costs almost nothing. The possibilities for ridiculously cheap remote temperature sensors and more are finally here. The software is new, the hardware is relatively new – and we need people working on software to make remote access easy. No guarantees here as I have only tested (and reported on) some of the features. Am important fix that made this practical to use only came through in the early hours of this morning – there will be bugs but at least it’s a starting point – all you have to lose is a little time.

Probably the Cheapest WIFI Computer in the World (ESP8266+LUA) - [Link]

5 Jan 2015


The MCP6V01 auto-zeroed op-amp features an ultra low offset voltage (VOS) and high common mode rejection ratio (CMRR), which makes it applicable to temperature measurement. The MCP6V01 thermocouple auto-zeroed reference design demonstrates how to measure electromotive force (EMF) voltage at the cold junction of the thermocouple in order to accurately measure temperature at the hot junction.

The difference amplifier is implemented using the MCP6V01 and 0.1% tolerance resistors. It amplifies the EMF voltage at the cold junction of the thermocouple. The MCP9800 senses temperature at the type K thermocouple’s connector. It should be located as close as possible to the connector on the PCB. This measurement is used to perform cold junction compensation for the thermocouple measurement. The MCP1541 provides a VREF (4.1V) to the internal 10-Bit ADC of the PIC18F2550 and sets the reference voltage for the difference amplifier. The CVREF is the internal comparator voltage reference of PIC18F2550, which is a 16-tap resistor ladder network that provides a selectable reference voltage. The MCP6001 buffer amplifier eliminates the voltage reference output impedance problem and produces the voltage VSHIFT.

The 2nd order RC low-pass filter that is implemented in this circuit can remove the high frequency noise and aliasing at the ADC input. The ADC of PIC18F2550 completes the analog-to-digital conversion. The data will be transferred to the PC using the USB interface. The thermal management software on PC is used to perform data display to show the real-time temperature and apply cold junction compensation and data linearization to determine the actual temperature of the thermocouple’s hot junction (weld bead).

Thermocouple Auto-Zeroed Reference Design - [Link]

5 Jan 2015


by Beke András @ bekeband.hu:

An black and white monitor needs to improve and repair from about 1990-th. The repair of device was not difficult but it caused troubles for the testing and setting of the monitor. We have a pattern TV generator, but this instrument are produce on the composite video signal for monitor. Unfortunately this monitor is demand not compozite signal instead of horizontal sync, vertical sync, and lightning signal. (video signal). Whereas the monitor host machine is not available – in fact I don”t know exactly what kind of equipment, perhaps a kind of mass spectrometer or something -, we need necessary a appropriate video signal source.

Video generator with PIC - [Link]

3 Jan 2015

by Patrick Hood-Daniel @ youtube.com:

In this video, I introduce the concept of I2C or TWI and explain the common use of the protocol and how to set it up. This is part one. Part two will delve into the circuit that we will use for the example.

I2C/TWI (Two Wire Interface) Tutorial - [Link]

2 Jan 2015


This project embodies the concept of I2C bus standard. It signifies how important to know the I2C devices and how they will be integrated. There are a lot of innovation can be made using the standard and more people are attracted to get involve in the embedded world professionally or just as hobbyist. The number of I2C devices included in this project may develop new ideas and designs.

The design includes 8-Bit Microchip PIC18F14K22 microcontroller which serves as the master of the I2C bus communication principle. The PCA9547D device is an 8-channel I2C-bus multiplexer with reset that communicates with the I2C devices one at a time. The PCA9500 device is an 8-bit I/O expander with an on-board 2-kbit EEPROM that simplifies the connection of LCD to the multiplexer. The MCP9801-M/MS device is a 2-Wire High-Accuracy Temperature Sensor for temperature monitoring. The 24LC025/ST device is a 2.5V, 2 Kbit Addressable Serial EEPROM (Tape and Reel) with no WP pin for firmware application. The MCP3221A0T-I/OT and TC1321EOATR devices are both for data conversion. The MCP3221A0T-I/OT is a Low Power 12-Bit A/D Converter With I2C Interface and the TC1321EOATR device is a 10-Bit Digital-to-Analog Converter with Two-Wire Interface. The MPL115A1 device is Miniature I2C Digital Barometer for pressure sensing applications. The MCP79400-I/MS is a Battery-Backed I2C™ Real-Time Clock/Calendar with SRAM and Protected EEPROM for applications that includes time. The PCA9530D device is a 2-bit I2C-bus LED SMBus I/O expander optimized for dimming LEDs in 256 discrete steps for Red/Green/Blue (RGB) color mixing and backlight applications. The 2X16 LCD is for display and monitoring application.

The design is very versatile since it opens up ideas to innovate. It is an excellent project for embedded system application. There are a lot of student will be attracted to develop their own design.

Interfacing MCU to various I2C Devices XD - [Link]





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