Jon Gabay writes:
Current measurement and control are an integral part of any power sensitive system. While most of us have used ammeters to measure current, it is unlikely that budget, space and other practical constraints will allow design engineers to specify an ammeter as part of a finished product; more likely, we will embed some current measurement technique within a given design.
Current measurement has a wide range of uses. Some of these are:
- Making sure a power supply is not damaged by receiving too much current.
- To estimate the rotational speed of a motor (the speed of a motor is directly proportional to the amount of current applied to it).
- To check whether an LED has correct illumination.
- To determine how much current is being applied to a battery pack during charging (so as to prevent overcharging or overheating the batteries).
- To measure the amount of current being applied to a circuit from the battery pack, enabling estimation of the battery life.
Active Current Measurement Saves Power, Enhances Safety - [Link]
This temperature measuring project has a variety of range from -55 to +125 degree centigrade indicating on four common anode seven segment display module.The project measures an accurate temperature value point to point.
The main sensing part of the project is the semiconductor DS1820.It is based an one wire protocol device manufactured by Dallas semiconductor comes in different resolution such as DS18 S20(9-bit resolution), DS18B20 (12-bit resolution) etc.A microcontroller(AT89C2051) controls whole circuit function like receiving the serial data from DS1820 and converting the value for displaying the seven segment module.
DS1820 Digital Thermometer - [Link]
Project is about a method to measure level of liquid using pressure sensors. Though not a new idea, the design has been done with following features in mind, Scalability, Cost, Feature Set
Non Contact Wireless Liquid Level Gauge - [Link]
This project is about building a PC-based temperature and relative humidity logger using the chipKIT Uno32 board and the DHT11 sensor. The DHT11 sensor is directly plugged into four I/O pins of the Uno32 board and is powered through the I/O pins. This project is probably an easiest way to setup an ambient room monitoring system for a server room. The Uno32 reads the temperature and relative humidity from the DHT11 sensor at preset interval and sends the data to PC through the USB-UART interface. A PC application is developed using the open-source Processing programming platform to log data onto an ASCII file. The PC application also displays the real-time temperature and relative humidity on computer screen.
PC based data logger using chipKIT Uno32 – [Link]
The AVR Stick is a simple data logging device that instantiates itself as an HID keyboard and reports the voltages, along with a ‘timestamp,’ from two pins on an ATtiny85. The device uses open source firmware availabe from Objective Development (http://www.obdev.at/vusb/) called V-USB to implement the USB 1.1 standard. The code that runs the application was based on the EasyLogger example application from Objective development.
AVR Stick – A simple USB data logging device - [Link]
USBTemp provides a thermometer. It is based on the DS18S20 digital thermometers. In addition, the thermometer connects to an USB port – you can read the temperature using a commandline tool. In combination with RRDTool you can easily create temperature graphs
USBTemp – USB temperature measurement - [Link]
20 Amps DC Ammeter using very low value resistance of 0.01 Ω
- Supply voltage. symmetric power (+ -12)
- Maximum current measure. 20A
- With Possibility of increasing the measurement range
- Resolution 10mA
20 Amps DC Ammeter - [Link]
Dilshan developed a precision event logger based on the PIC16F73 and some binary ripple counters from the CMOS logic family. The project uses a 2Mhz reference clock, and is capable of measuring events from 0.02 to 6.8 seconds long. [via]
The counter gets activate and deactivate in positive edge of the input signal. Thanks to the wider operating voltage of the CMOS ICs this counter may be able to handle +5V to +15V of input signal. At the end of the counter session system release total tick count to the RS232 interface and it can receive through any serial terminal software. When applying the inputs it is recommended to maintain minimum of 100ms of interval between each session.
Precision event logger measures 0.02 to 6.8 seconds - [Link]
The example cases discussed in this application report provide a basic understanding of what needs to be done at production, as well as on the application level, to achieve the aforementioned goals. The associated software provides library functions to interface and communicate with the bq27410 fuel gauge, applicable to any USB-equipped MSP430 device. The software also includes a demo application that integrates the USB stacks and the fuel gauge library functions to read the battery information from the fuel gauge and transmit it to the PC through USB Communications Device Class (CDC).
MSP430 based USB Li-Ion battery charger with fuel gauge - [Link]