LM3916 is a dedicated IC for VU LED meter. Unlike LM3915 which have 3dB step between voltage levels, the LM3916 have nonlinear steps: -20, -10, -7, -5, -3, -1, 0, +1, +2, +3db, just like old school analog VU meters. I saw in YouTube an interesting commercial LED VU meter, which imitates the needle movement in analog VU meters and I thought I can make a similar one. All I needed I found in the datasheet of LM3916.
LED VU Meter with LM3916 - [Link]
Here is another piece of laboratory equipment – LC meter. This type of meter, especially L meter is hard to find in cheap commercial multimeters.
Schematic of this one came from this web page: https://sites.google.com/site/vk3bhr/home/index2-html
It uses PIC microcontroller 16F628A, and because I recently acquired a PIC programmer, I decided to test it with this project. Following the above link you will find the original schematic, PCB, source and HEX files for programing the microcontroller and detailed description.
Simple PIC LC meter - [Link]
by BasinStreetDesign @ instructables.com:
I had a bunch of random inductors in some random drawers and I wanted to know what values they were. These values are quite often not obvious by looking at the device. Colour codes for old ones were not standardized and some of the coloured rings on inductors can be faded or discoloured so that its impossible to tell what they are. Others may be unmarked and any that are hand-wound are just guess work without a meter. So I decided to make an inductance and capacitance meter which would be fairly accurate and work over several decades of value from a few nano-Henries to a few milli-Henries and also from a few pico-farads to about a micro-farad (hopefully). Sounded easy – what could go wrong?
Inductance/Capacitance Meter Saga - [Link]
Here’s a cool Mini LED volume towers project by Ben Finio. He writes a complete step-by-step instructions here:
The inspiration for this project started when I saw a variety of awesome stereo LED towers on YouTube (also referred to as VU meters). Many of the videos showed the end result, and maybe a slideshow of the assembly process, but lacked complete build details or a circuit diagram. So, I set out to find out how they worked, and build my own “mini” desktop version that would go nicely with computer speakers, instead of a big living room stereo. This Instructable will give you complete directions to assemble the required circuit (even if you have no electronics experience – you can even do it without soldering), build two LED towers, and hook them up to an audio input so you can simultaneously drive them and listen to music.
Mini LED volume towers (VU meters) - [Link]
Here’s a cheap and simple Laser Power Meter LPM for small power source, based on “MarioMaster LPM meter” by Davide Gironi:
This type of meter uses a ThermoElectric Cooling module (TEC) to measure the power of a laser. The TEC will absorb the laser light, and transform the heat generated by the laser beam to an electrical signal.
An operational amplifier is used then to amplify the signal and ouput it to a volt meter.
Voltage meter will display the power in W unit of the laser beam you are testing.
The TEC takes a little amount of time to heat, so wait until your reading became stable.
This type of meter is simple and cheap to build.
It can measure laser power up to 2W, with an accurancy of +-10mW.
A cheap and simple Laser Power Meter LPM for small power source - [Link]
Here’s a low-cost single phase energy metering solution using Microchip’s MCP3909 metering ADC and PIC18F25K20 8-bit microcontroller. App note can be found here.
The meter was tested for a range of current from 0.1A to 20A using the Fluke 6100A Electrical Power Standard. Measurement results are visible on the LCD or on the Pulse Output. This document is intended to provide guidance for designers who are interested in using Microchip’s MCP3909 Metering ADC with synchronous sampling and PGA on current channel, and the low-cost high performance PIC18F25K20 microcontroller.
Low-Cost Shunt Energy Meter using MCP3909 and PIC18F25K20 - [Link]
Daniel @ panstamp.com writes:
We know many of you were wondering when we’ll release a power meter compatible with panStamp. And here we are, sooner as expected, with a first prototype. We at panStamp are passionate about simplicity so you may guess that either electronics or firmware application have been designed to be as compact and efficient as possible.
panStamp Power meter board - [Link]
The MAX71020 is a single-chip, analog front-end to be used in high-performance revenue meters. It contains the compute engine found in Maxim’s fourth-generation meter SOC and an improved ADC, and interfaces to the host microcontroller of choice over a SPI interface.
MAX71020 Single-Chip Electricity Meter - [Link]