This Instructable will teach you how to use the Arduino Analog ports. johnag @ instructables.com writes:
Digital Voltmeters (DVMs) are a special case of Analog to Digital converters- A/DCs.- they measure voltage – and are usually a function of a general purpose instrument called a Digital Multimeter( DMMs), commonly used to measure voltages in labs and in the field. DMMs display the measured voltage using LCDs or LEDs to display the result in a floating point format. They are an instrument of choice for voltage measurements in all kinds of situations. This instructable will show you how to use the Arduino as a DC DVM (Direct Current Digital Volt Meter).
Make a Mini Arduino programmable 4 channel DC-DVM - [Link]
Raj @ embedded-lab.com writes:
A light meter is used to measure the intensity of illumination in a given area. It is widely used in schools, warehouses, factories, hospitals, office buildings, museums, art-galleries, parking garages, stadiums, and many more, to measure and maintain proper lighting levels. The intensity of illumination is usually expressed in Lux or foot-candles. As the 4th project in our chipKIT tutorial series, today we are going to build a digital light meter using the chipKIT Uno32 board and the BH1750 digital light sensor. This project uses Digilent’s chipKIT Basic I/O shield for displaying the measured light intensity in Lux, foot-candles, and Watts/m^2 units.
chipKIT Project 4: Digital light meter - [Link]
Jan_Henrik @ instructables.com writes:
In this project i want to show and explain you a range sensor with ultrasonic and a 20×04 lcd screen. I wrote the code for this project myself and added lots of comments, so that everybody can understand it and use it for other projects (maybe a light range sensor?!). It is easy to build and much more easier to program, it just requires a few cheap parts and can run on battery, for a portable rangefinder.
The maximum rated range is 500 cm, the range is measured 20 times per seccond. It is Displayed on a lcd screen which is 20×4 chars big, it has a custom start message, and it can have a custom design while measuring. It will have a backlight LED and can run on every arduino, which has I²C communication. That mean you can run it on an Arduino nano, which is very small. It also requires 5V so it has to be a 5V version of an Arduino.
Arduino ultrasonic range finder - [Link]
The Logic Pirate is an inexpensive yet capable open source logic analyzer. For just 30 bucks it can sample 8 channels, 256K samples per channel, at a blazing (overclocked!) 60 MILLION samples per second! It’s designed to support the SUMP logic analyzer protocol on Jawi’s open source software that works on most platforms. [via dangerousprototypes.com]
Logic Pirate 8 channel, 256K sample, 60MSPS logic analyzer - [Link]
I’m currently testing all the hardware on the board. So far I got the MCU running, managed to talk to the 74HC595. Also the DC-DC converter works quite well, so does the voltage reference.
The board currently uses way too much power, that’s why I need to consider underclocking the microcontroller to 4MHz.
I still need to get the ADC and SD card working, I haven’t had much luck with that so far.
I already have a few ideas on changes I want to make on the board, a blog post about them coming up soon.
UPDATE: miniLOG – Precision Standalone Voltage Logger - [Link]
karllunt @ www.seanet.com writes:
This is pretty much one of those required projects; everyone builds a datalogger in an Altoids can. But each is different and I enjoyed making mine.
Uses ATmega328P (low power, 32K flash for lots of program space)
Uses Maxim/Dallas DS1337 Real Time Clock (uses I2C)
Logs data to microSD flash card, readable on PC (uses FAT32)
Runs on two AAA alkaline batteries
Low power draw (exact consumption varies based on SD card used)
Supports RS-232 for entering commands
Uses CR2032 lithium coin cell for RTC backup
Uses Analog Devices TMP36 for temperature sensor (not shown, it gets wired to the green four-position terminal shown below)
Uses SparkFun 3.3VDC boost converter to provide stable voltage even as batteries die
Datalogger in an Altoids can - [Link]
Here’s an interesting open source project on Kickstarter the Re:Load Pro by Nick Johnson of Arachnid Labs:
A constant current load for testing your projects. 6 amps, 60 volts and 25 watts in a workbench-friendly package with a USB interface.
The Re:Load Pro is an active load. It acts as a current sink, always drawing the same amount of current regardless of the voltage across it.
Active loads are incredibly useful for all sorts of electronics testing requirements. You can use one to see how a power supply performs under load, check if a battery lives up to its manufacturer’s specifications for capacity or current draw, test motor drivers, or a variety of common constant-current tasks, such as testing LEDs, or even doing electroplating. With computer control of the load, you can even do your own IV-curve tracing.
Re:Load Pro – A DC active load - [Link]
Why do digital oscilloscopes appear noisier than traditional analog oscilloscopes?
Dave busts the myth that digital scopes are noiser than analog scopes, and demonstrates what inherent advantages digital scopes can have over analog scopes in terms of true waveform capture. And also why your analog scope may be hiding important signal detail from you.
Demonstrations of how memory depth, analog bandwidth, averaging, and intensity graded displays can all effect the signal detail you see on your digital oscilloscope.
And how long exposure camera shots on analog oscilloscopes can reveal detail you can’t see with your eyes.
EEVblog #601 – Why Digital Oscilloscopes Appear Noisy - [Link]
This is a review of the Sanwa PC7000 Multimeter. Video has two parts, Part1 and Part2.
Review: Sanwa PC7000 Multimeter - [Link]
In this episode Shahriar repairs an Agilent 86120B Multi-Wavelength Meter. The instrument reports “E14 Data Acquisition Problem” which corresponds to a potential internal HeNe reference laser failure. After the instrument disassembly, the old HeNe laser is removed and its optical power is compared to that of a new laser. The measurements confirm that the old laser has significantly deteriorated in output light intensity. The new laser is fitted inside the unit and the error message is eliminated. The free-space optic portion of the instrument is revealed and the principle operation is reviewed. Various components of the Michelson Interferometer is examined.
To test the correct operation of the instrument, a single tone semiconductor laser is applied to the unit and the result is compared to a different wavelength meter. The concept behind the operation of a Fabry-Perot laser is also presented before the signal is applied to the wavelength meter.
Teardown, Repair and Experiments of an Agilent 86120B Multi-Wavelength Meter - [Link]