Mains Power Detector For A Thing For Internet

July 6, 2014 by Brian Benchoff 38 Comments

inductor The Internet of Things is fast approaching, and although no one can tell us what that actually is, we do know it has something to do with being able to control appliances and lights or something. Being able to control something is nice, but being able to tell if a mains-connected appliance is on or not is just as valuable. [Shane] has a really simple circuit he’s been working on to do just that: tell if something connected to mains is on or not, and relay that information over a wireless link.

There are two basic parts of [Shane]’s circuit – an RLC circuit that detects current flowing through a wire, This circuit is then fed into an instrumentation amplifier constructed from three op-amps. The output of this goes through a diode and straight to the ADC of a microcontroller, ready for transmission to whatever radio setup your local thingnet will have.

It’s an extremely simple circuit and something that could probably be made with less than a dollar’s worth of parts you could find in a component drawer. [Shane] has a great demo of this circuit connected to a microcontroller, you can check that out below.

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The Disintegrated Op Amp

July 5, 2014 by Brian Benchoff 31 Comments

741 By now we’ve all seen the ‘Three Fives’ kit from Evil Mad Scientist, a very large clone of the 555 timer built from individual transistors and resistors. You can do a lot more in the analog world with discrete parts, and [Shane]’s SevenFortyFun is no exception: it’s a kit with a board, transistors, and resistors making a very large clone of the classic 741 op-amp, with all the parts laid bard instead of encapsulated in a brick of plastic.

[Shane] was inspired by the analog greats – [Bob Pease], [Jim Williams], and of course [Bob Widlar], and short of mowing his lawn with goats, the easiest way to get a feel for analog design was to build some analog circuits out of individual components.

[Shane] has a few more kits in mind: a linear dropout and switching regulators are on the top of the list, as is something like the Three Fives kit, likely to be used to blink giant LEDs.

The Cheapest Crystal Oven

July 5, 2014 by Brian Benchoff 33 Comments

The crystals you’ll find attached to microcontrollers or RTCs are usually accurate to 100 parts per million at most, but that still means if you’re using one of these crystals as a clock’s time base, you could lose or gain a second per day. For more accuracy without an atomic clock, a good solution is an oven controlled crystal oscillator – basically, a temperature controlled crystal. It’s not hard to build one, and as [Roman] demonstrates, can be built with a transistor and a few resistors.

The heating element for this OCXO are just a few resistors placed right on the can of a crystal. A thermistor senses the heat, and with more negative feedback than the Hackaday comments section, takes care of regulating the crystal’s temperature. A trimpot is used for calibrating the temperature, but once everything is working that can be replaced with a fixed resistor.

This deadbugged circuitry is then potted in five minute epoxy. That’s a bit unconventional as far as thermal management goes, but the results speak for themselves: [Roman] can get a clock with this circuit accurate to a few seconds per year.

TI’s New Family Of WiFi Chips

July 4, 2014 by Brian Benchoff 30 Comments

cccc Texas Instruments’ CC3000 WiFi chip is the darling of everyone producing the latest and greatest Internet of Thing, and it’s not much of a surprise: In quantity, these chips are only $10 a piece. That’s a lot less expensive than the WiFi options a year ago. Now, TI is coming out with a few new modules to their WiFi module family, including one that includes an ARM micro.

The CC3000 has found a home in booster packs, breakout boards for the Arduino, and Spark, who are actually some pretty cool dudes.Still, the CC3000 has a few shortcomings; 802.11n isn’t available, and it would be really cool if the CC3000 had a web server on it.

The newest chips add these features and a whole lot more. [Valkyrie] got his hands on a CC3100Boost board and was pleased to find all the files for the webserver can be completely replaced. Here’s your Internet of Things, people. The CC3200 is even better, with a built-in ARM Cortex M4 with ADCs, a ton of GPIOs, an SD card interface, and even a parallel port for a camera. If you’re looking to pull a hardware startup out of your hat, you might want to plan your Kickstarter around this chip.

It’s all very cool stuff, and although the bare chips aren’t available yet, you can get an eval module from TI, with an FCC certified module with the crystals and antenna coming later this year.

Developed On Hackaday: Demonstration Video And Feedback Request

July 2, 2014 by Mathieu Stephan 143 Comments

http://www.youtube.com/watch?v=RYaz-s5SXCc

For months our dear Hackaday readers have been following the Mooltipass password keeper’s adventures, today we’re finally publishing a first video of it in action. This is the fruit of many contributors’ labor, a prototype that only came to be because of our motivation for open hardware and our willingness to spend much (all!) of our spare time on an awesome project that might be just good enough to be purchased by others. We’ve come a long way since we started this project back in December.

In the video embedded above, we demonstrate some of our platform’s planned functionalities while others are just waiting to be implemented (our #1 priority: PIN code entering…). A quick look at our official GitHub repository shows what it took to get to where we are now. What’s next?

We need your input so we can figure out the best way to get the Mooltipass in the hands of our readers, as our goal is not to make money. The beta testers batch has just been launched into production and I’ll be traveling to Shenzhen in two weeks to meet our assembler. When materials and fabrication are taken into account we expect each device to cost approximately $80, so please take 3 seconds of your time to answer the poll embedded below: (poll has ended)

An Online Course For FPGA And CPLD Development

June 27, 2014 by Brian Benchoff 16 Comments

FPGA

Over on the University of Reddit there’s a course for learning all about FPGAs and CPLDs. It’s just an introduction to digital logic, but with a teacher capable of building a CPLD motor control board and a video card out of logic chips, you’re bound to learn something.

The development board being used for this online course is an Altera EMP3032 CPLD conveniently included in the Introduction to FPGA and CPLD kit used in this course. It’s not a powerful device by any measure; it only has 32 macrocells and about 600 usable gates. You won’t be designing CPUs with this thing, but you will be able to grasp the concept of designing logic with code.

Future lessons include building binary counters, PWM-controlled LEDs, and a handheld LED POV device. In any event, it’s a great way to learn about how programmable logic actually works, and a fairly cheap way to get into the world of FPGAs and CPLDs. Introductory video below.

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Homebrew Programming With Diodes

June 26, 2014 by Brian Benchoff 18 Comments

diode

Diode matrices were one of the first methods of implementing some sort of read only memory for the very first electronic computers, and even today they can be found buried deep in the IPs of ASICs and other devices that need some form of write-once memory. For the longest time, [Rick] has wanted to build a ROM out of a few hundred diodes, and he’s finally accomplished his goal. Even better, his diode matrix circuit is actually functional: it’s a 64-byte ROM for an Atari 2600 containing an extremely simple demo program.

[Rick] connected a ton of 1N60 diodes along a grid, corresponding to the data and address lines to the 2600’s CPU. At each intersection, the data lines were either unconnected, or tied together with a diode. Pulling an address line high or low ([Rick] hasn’t posted a schematic) pulls the data line to the same voltage if a diode is connected. Repeat this eight times for each byte, and you have possibly the most primitive form of read only memory.

As for the demo [Rick] coded up with diodes? It displays a rainbow of colors with a black rectangle that can be moved across the screen with the joystick. Video below.

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