voltmeter

20 Articles

Fubarino Contest: Micro Voltmeter

December 28, 2013 by 6 Comments

recorte

This collection of hardware is a diy voltmeter. It can measure up to 17V with 1 microvolt resolution while taking seven samples per second. The LTC2400 ADC board is used to make the measurements, with the Arduino processing the output and taking care of the display and user input buttons.

In addition to showing off what the thing can do in the video after the break, [Luis] gives us a look at the easter egg he added to the project. When you have a source that is very precisely 12V, the meter will read out Hackaday.com!

Incidentally the display used in this hack is one we’ve seen before. Obviously this is a convenient way to add interactive controls to your projects.

This is an entry in the Fubarino Contest for a chance at one of the 20 Fubarino SD boards which Microchip has put up as prizes!

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Turning Cheap Voltmeters Into I2C Displays

August 25, 2013 by 7 Comments

Voltmeter I2C Displays

[Tom] needed 8 displays for a project. He wanted to to control them over I2C, and was trying to reduce cost. Some vendors make I2C controllable seven segment displays, but they cost about $10 each. [Tom] figured he could hack cheap voltmeters to get the same results for about $3 a pop.

The voltmeters that [Tom] bought used a 8 bit STM8S003F3P6 microcontroller. He reverse engineered the device and re-created the schematic to find out where the I2C and programming pins would be. Then he hooked it up to a STM8 Discovery development board, which has an integrated programmer.

With the hardware figured out, it was time for new firmware. Fortunately, [ba0sh1] had already written firmware for a similar purpose which could easily be adapted. The code implements a software I2C slave, which reads data off the bus and displays it. It’s all available on Github.

The end result is a I2C controlled display for a third of the cost. Next time you need a bunch of these in a project, consider picking up some cheap voltmeters.

Award Clock Put To Good Use As A Bench Meter

January 21, 2013 by 6 Comments

award-clock-turned-voltage-meter

The motivation industry turns out these type of award trinkets by the millions. Here’s a way to actually put the thing to use. Instead of displaying time, the clock dial serves as the readout of a voltage meter.

When we first saw this post we assumed that the hack used some type of coil injection to drive the hands. But it turns out that this is mechanically driven. The image above shows the stepper motor which is mounted behind the clock. Its drive shaft is coupled with the adjustment knob on the back of the clock. The precision of the motor lets the PICAXE set the clock dial based on the number of motor steps. The hour hand shows the tens value with the minutes serving as ones (base 10, not base 60). This means the top measurable voltage is 12V — when the hour hand is at 12 the measurement is 0 volts plus tenths of a volt from the minute hand. With the dial taken care of the rest of the project focuses on measuring the voltage using the ADC, which has an upper limit of just 5V. This is overcome with a simple voltage divider.

After the break you can see the accuracy of the rig as it performs measurements next to a digital voltmeter.

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$4 Volt Meter From A Dollar Store Pedometer

November 12, 2012 by 37 Comments

[Paulo]’s got a few solar panels on his shed, and while he does have a fairly nice setup with a battery charge controller, he found himself looking around for a panel voltmeter. Of course you can buy a panel voltmeter for under $20, but [Paulo] wanted something that fit his 4-4-4 plan; his voltmeter should cost under $4, draw less than 4mA, and last for 4 years. The jury is still out on the 4 year qualifier, but he did manage to meet his other goals by repurposing a dollar store pedometer as a voltmeter.

The pedometer in question is a very simple device. After inspecting the PCB, [Paulo] found it operates by looking at a trigger pin and incrementing the number on the display each time the circuit closed. [Paul] designed a very small PIC12F-powered circuit that reads the voltage of his batteries and triggers the pedometer’s LCD for every 10th of a volt. To display 12.6 Volts, [Paulo]’s code triggers the LCD 126 times, for example.

After wiring up the reset button so the display will go back down to zero for each new reading, [Paulo] encased his new volt meter in a plastic box. It’s not exactly a fast way of measuring voltage, but seeing as how that won’t change very fast, it’s the perfect solution for [Paulo]’s solar charger setup.

ultimate-breadboard

The Ultimate Breadboard – A Prototyping Station That Has It All

February 9, 2012 by 27 Comments

[Claudio] was working on a homebrew oscilloscope project when he started thinking about how unsuitable a standard breadboard is for a large-scale project. Rather than adding components on top of components until they became what he lovingly calls a “fragile, unforgiving crapstack”, he decided to build himself the Ultimate Breadboard.

He packed so much into his design, that it’s honestly hard to know where to begin describing it. Aside from an appropriately large breadboarding surface embedded in the center of the console, he added a power supply to the left hand side, which sits just below an Avr-Net-IO board. The right side of the console features an Arduino NG, and a pair of level converters. He also added some LED-based VU meters, a couple of 7-segment displays, an LCD display, an analog voltmeter, along with plenty of I/O connectors.

The Ultimate Breadboard might look a bit daunting at first, but it seems like an awesome setup on which to do any sort of prototyping. Be sure to check out the video below for more details and to see [Claudio] give a tour of the device.

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Hackaday Links: December 7, 2011

December 7, 2011 by 12 Comments

LED Neurons

[Alexandra Olivier] put up an art installation at Wellesley College that looks like a bunch of neurons built out of LEDs. The neurons are connected to a couple PIR sensors and ‘fire’ whenever movement is detected. The result is a lot like being inside a brain. Fitting, then, that the installation is called Social Synapses.

Last year’s big toy was always evil, though

Last year, [Andrew] had to fight the throngs of shoppers to get the must have toy of the season, a Zhu Zhu pet. Since these robotic hamster things have spent the last 11 months in the back of a closet, it seems reasonable to make them evil. They’re still not as evil as a demonic Furby….

So we call it a bifocal, right?

There’s an old photography trick for a really hacky macro setup – just turn the lens around. Well, what if you wanted automatic metering and flash control? Simple, just electrically reverse the lens. Bonus points for being able to use the lens regularly as well.

Control all the bands

Well here’s something cool: an all-in-one USB 315mhz, 433mhz, and 868mhz transceiver. What can you do with it? Well, [codeninja] can control the outdoor lights for two of his neighbors, open gates and doors, crash his weather station, and just about anything else in those bands. It’s pretty much like war driving for important stuff nobody cares about.

So this is our favorite holiday now

There’s a Dutch tradition to play Sinterklaas and make someone a present. [Jenor] decided to build an antique-looking DC voltmeter with a pair of vacuum tubes. The tubes don’t work anymore, but the heaters still provide a nice warm glow. It’s a bit large to be regularly used as a piece of test equipment, but it really does look awesome. Very steampunkey, and it’s the though that counts anyway.