hardware

1803 Articles

Dumb STB Gets Smart

September 1, 2017 by 5 Comments

[Vincent Deconinck] gave a fresh lease of life to an old set top box by adding a few Euro’s worth of hardware and some software smarts. The device in question is an old VOOcorder – a Cisco set-top box provided by VOO, his cable service provider in Belgium.

The VOOcorder doesn’t have any WiFi hardware or browser / app based interfaces. It’s a simple device controlled either via an IR remote or front panel buttons. [Vincent] added an ESP8266 and hooked it up to the IR receiver on the set-top box. He also set it up as an SPI slave to the front panel VFD display controller and connected it to the debug serial interface of the VOOcorder as well. The software, on the other hand, required a lot more work consisting of code running on the ESP itself, several HTML pages and JavaScript code for the browser front end, and a few scripts running in the background.

The result was bidirectional interactivity from within a browser, allowing him to send commands and receive status information as well as providing a user-friendly search interface. Further, his browser interface was integrated with information from the service providers website letting him do scheduling and recording of programs. The stuff that interested us is how he sniffed out the IR signals, figured out the SPI protocol used by the front panel controller, and implemented SPI-slave mode for the ESP8266. [Vincent] was surprised that such a cheap device could handle three distinct web servers while parsing two message streams without a hitch.

It’s a great hack showing us how to use super cheap electronics to upgrade and modernize old hardware. Check out the two videos after the break – showing a demo of the hack in action, and a walk through of the hardware modifications.

Continue reading “Dumb STB Gets Smart” →

Repurposing Moving Coil Meters To Monitor Server Performance

August 31, 2017 by 11 Comments

Snazzy analog meters can lend a retro flair to almost any project, but these days they often seem to be retasked as indicators for completely different purposes than originally intended. That’s true for these Vu meters repurposed as gauges for a Raspberry Pi server, and we think the build log is as informative as the finished product is good-looking.

As [MrWunderbar] admits, the dancing needles of moving-coil meters lend hipster cred to a project, but getting his Vu meters to cooperate and display network utilization and disk I/O on his Raspberry Pi NAS server was no mean feat. His build log is full of nice details on how to measure the internal resistance of the meter and determine a proper series resistor. He also has a lengthy discussion of the relative merits of driving the meters using a PWM signal or using a DAC; in the end, [MrWunderbar] chose to go the DAC route, and the video below shows the desired rapid but smooth swings as disk and network usage change. He also goes into great depth on pulling usage parameters from psutil and parsing the results for display on the meters.

Looking for more analog meter goodness? We saw a similar CPU load meter a few months back, and there was this mash-up of Nixies and old meters for a solar energy CEO’s desk.

Continue reading “Repurposing Moving Coil Meters To Monitor Server Performance” →

A Very Accurate Current Probe

August 30, 2017 by 13 Comments

There’s many different ways of measuring current. If it’s DC, the easiest way is to use a shunt resistor and measure the voltage across it, and for AC you could use a current transformer. But the advent of the Hall-effect sensor has provided us a much better way of measuring currents. Hall sensors offers several advantages over shunts and CT’s – accuracy, linearity, low temperature drift, wider frequency bandwidth, and low insertion loss (burden) being some of them. On the flip side, they usually require a (dual) power supply, an amplification circuit, and the ability to be “zero adjusted” to null output voltage offsets.

[Daniel Mendes] needed to measure some fairly high currents, and borrowed a clip-on style AC-DC current probe to do some initial measurements for his project. Such clip on current probes are usually lower in accuracy and require output DC offset adjustments. To overcome these limitations, he then built himself an invasive hall sensor current probe to obtain better measurement accuracy (Google Translated from Portugese). His device can measure current up to 50 A with a bandwidth stretching from DC to 200 kHz. The heart of his probe is the LAH-50P hall effect current transducer from LEM – which specialises in just such devices. The 25 mV/A signal from the transducer is buffered by an OPA188 op-amp which provides a low output impedance to allow interfacing it with an oscilloscope. The op-amp also adds a x2 gain to provide an output of 50 mV/A. The other critical part of the circuit are the high tolerance shunt resistors connected across the output of the LAH-50P transducer.

The rest of his design is what appears to be a pretty convoluted power supply section. [Daniel] wanted to power his current probe with a 5V input derived from the USB socket on his oscilloscope. This required the use of a 5 V to 24 V boost switching regulator – with two modules being used in parallel to provide the desired output power. A pair of linear regulators then drop down this voltage to +15 / -15 V required for the trasducer and op-amp. His blog post does not have the board layout, but the pictures of the PCB should be enough for someone wanting to build their own version of this current sensor.

Mouse Mis-Clicking? We Got You.

August 30, 2017 by 33 Comments

A mouse with malfunctioning buttons can be a frustrating to deal with — and usually a short leap to percussive maintenance. Standard fixes may not always last due to inferior build quality of the components, or when the microswitch won’t close at all. But, for mice that double/triple-click, will release when dragging, or mis-click on release, this Arduino-based hack may be the good medicine you’re after.

Instructables user [themoreyouknow]’s method cancels click malfunctions by latching the mouse’s controller switch trace to ‘on’ when pressed, keeping it there until the button normally closed contact closes again completely. Due to the confined spaces, you’ll want to use the smallest Arduino you can find, some insulating tape to prevent any shorts, and care to prevent damaging the wires this process adds to the mouse when you cram it all back together.

Before you take [themoreyouknow]’s guide as dogma, the are a few caveats to this hack; they are quick to point out that this won’t work on mice that share two pins between three buttons — without doing it the extra hard way, and that this might be trickier on gaming or other high-end mice, so attempt at your own peril.

Speaking of gaming mice, we recently featured a way to add some extra functionality to your mouse — cheating optional — as well as how to stash a PC inside an old Logitech model.

A Diode By Any Other Name

August 29, 2017 by 25 Comments

As active devices go, it doesn’t get much simpler than a diode. Two terminals. Current flows in one direction and not in the other. Simple, right? Well, then there are examples with useful side effects like light emitting diodes. [GreatScott] points out that there are other useful diodes and, in particular, he posted a video covering Schottky and Zener diodes.

These special diodes have particular purposes. A Schottky diode has a very low voltage drop and fast switching speed. Zener diodes have application in simple voltage regulation.

Continue reading “A Diode By Any Other Name” →

Floating Ants And Drops Of Liquid With An Acoustic Levitator

August 24, 2017 by 9 Comments

Amuse your friends, amaze your enemies, and perplex ants and other insects, insofar as they are capable of perplexment. Accomplish all this and more with this handy dandy homebrew acoustic levitator.

Before anyone gets to thinking about using this technique to build a hoverboard that actually hovers, it’s best that you scale your expectations way, way down. Still, being able to float drops of liquid and small life forms is no mean feat, and looks like a ton of fun to boot. [Asier Marzo]’s Instructable’s post fulfills a promise he made when he first published results for what the popular press then breathlessly dubbed a “tractor beam,” which we covered back in January. This levitator clearly has roots in the earlier work, what with 3D-printed hemispherical sections bristling with ultrasonic transducers all wired in phase. A second section was added to create standing acoustic waves in the middle of the space, and as the video below shows, just about anything light enough and as least as cooperative as an ant can be manipulated in the Z-axis.

There’s plenty of room to expand on [Asier]’s design, and probably more practical applications than annoying bugs. Surface-mount devices are pretty tiny — perhaps an acoustic pick and place is possible?

Continue reading “Floating Ants And Drops Of Liquid With An Acoustic Levitator” →

Control The Air Conditioning With Slack

August 23, 2017 by 7 Comments

[Raphael Baron] needed a better way to control his office’s air conditioning units. Sure, they have remotes, but that’s too easy. [Raphael] came up with a solution that uses an ESP8266, a computer, IR LEDs, and a bot that runs on Slack.

[Raphael] built a prototype of the ESP8266 hardware on protoboard and used it to read and record the IR signals from the remote. Once he’d figured out the issues he was having with the IR library he was using, he could use it to send the IR commands to the AC unit. Since their office has two AC units, [Raphael] built a second prototype which had two IR LEDs but didn’t have the IR receiver. Using this he could turn both AC units on and off and set their temperatures.

For the server, [Raphael] turned to Clojure, a dialect of Lisp, which provides easy access to the Java Framework, mainly to get practice working with the language. The server’s main responsibility is to use Slack’s real-time API to listen for messages from a Slack bot and forward them to the ESP. In this way, a user talking to the Slack bot can send it messages which the server forwards to the microcontroller which, in turn, parses the messages and send IR commands to the AC units.

[Raphael] admits that this isn’t the most advanced, professional stuff, but it doesn’t matter. The schematics for the ESP8266 board and the code for both the ESP board and the server are available on GitHub. There seems to be a lot of hacks using Slack, such as this NERF Turret controlled by a Slack bot.  Or this jukebox that users can interact with by talking to a Slack bot.