Minimal MQTT: Networked Nodes

May 17, 2016 by Elliot Williams 32 Comments

Last time on Minimal MQTT, we used a Raspberry Pi to set up an MQTT broker — the central hub of a home data network. Now it’s time to add some sensor and display nodes and get this thing running. So pull out your ESP-8266 module of choice, and let’s get going.

For hardware, we’re using a WeMos D1 Mini because they’re really cute, and absolutely dirt cheap, but basically any ESP module will do. For instance, you can do the same on the simplest ESP-01 module if you’ve got your own USB-serial adapter and are willing to jumper some pins to get it into bootloader mode. If you insist on a deluxe development board that bears the Jolly Wrencher, we know some people.

NodeMCU: Getting the Firmware

We’re using the NodeMCU firmware because it’s quick and easy to get running. But you’re not stuck with NodeMCU if you want to go it alone: MQTT has broad support. [TuanPM] ported over an MQTT library to the native ESP8266 SDK and of course there’s espduino, a port for an Arduino-plus-ESP combo. He also ported the MQTT module to NodeMCU that we’ll be using today. Thanks, [TuanPM]!

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Hackaday Prize Entry: Wirelessly Charged Self-Heating Coffee Mug

May 16, 2016 by Gerrit Coetzee 14 Comments

Many productive hackers bleed a dark ochre. The prevailing theory among a certain group of commenters is that they’re full of it, but it’s actually a healthy sign of a low blood content in the healthy hacker’s coffee stream. [Bharath] is among those who enjoy the caffeinated bean juice on a daily basis. However, he’d suffer from a terrible condition known as cold coffee. To combat this, he built an app-enabled, wirelessly chargeable, self-heating coffee mug.

We know that most hackers don’t start off planning to build objects with ridiculous feature lists, it just happens. Is there an alternate Murphy’s law for this? Any feature that can be added will? The project started off as some low ohm resistors attached to a rechargeable power bank. A insulated flask with a removable inner stainless steel lining was chosen. The resistors were fixed to the outside with a thermal epoxy.

However, how do we control the resistors? We don’t want to burn through our battery right away (which could end up more literally than one would like), so [Bharath] added a Linkit One microcontroller from Seeed Studio. With all this power at his disposal, it was natural to add Bluetooth, a temperature sensor, and app control to the cup.

After getting it all together, he realized that while the insides were perfectly isolated from the liquids held in the flask under normal use, the hole he’d have to cut to connect to the charging circuit would provide an unacceptable ingress point for water. To combat this he added the wireless charging functionality.

With his flask in hand, we’re sure the mood boost from not having to slog through the dregs of a cold container of coffee will produce a measureable improvement in productivity. Video after the break.

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Concrete Table Just The Way You Like It

May 11, 2016 by Gerrit Coetzee 14 Comments

You need a coffee table, you need a dinner table. Do you really need two tables? [Shua] thinks the answer is “no”. That’s why he built this swinging countersink table out of concrete and a aluminum.

He started by making a simple half-scale prototype. Then a larger one. Through these explorations he learned how the table would be made, what kind of weight it needed, and how the mechanics needed to be constructed for the most stable table top.

Next he designed the final table in Autodesk Revit. This is software traditionally used for architecture. Since the table was to be made from concrete Revit’s useful set of concrete tools were useful for this project.

Most of the construction process was pretty standard. However, the use of CNC’d pink insulation as a mold for the concrete was interesting. The foam is closed cell, so it worked fine and gave a nice finish. The assembly was finished with a glass top and a carpeted base that contained a surge suppressor and two outlets. The table can be seen swinging between two positions in a video after the break.

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When The Smart Hits The Fan

May 10, 2016 by Dan Maloney 5 Comments

A fan used to be a simple device – motor rotates blades, air moves, and if you were feeling fancy, maybe the whole thing oscillates. Now fans have thermostats, timers, and IR remotes. So why not increase the complexity by making a smart fan with an IoT interface?

[Casper]’s project looks more like a proof of concept or learning platform than a serious attempt at home automation. His build log mentions an early iteration based on a Raspberry Pi. But an ESP8266 was a better choice and made it into the final build, which uses an IR LED to mimic the signals from the remote so that all the stock modes of the fan are supported. The whole thing is battery powered and sits on a breadboard on top of the fan, but we’ll bet that a little surgery could implant the interface and steal power internally. As for interfaces, take your pick – an iOS app via the SmartThings home automation platform, through their SmartTiles web client, or using an Amazon Echo. [Casper] mentions looking into MQTT as well but having some confusion; we’d suggest he check out [Elliot Williams]’ new tutorial on MQTT to get up to speed.

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Tiling Your TV Remote

May 8, 2016 by Gerrit Coetzee 35 Comments

The Tile is a small Bluetooth chip, speaker, and enough battery for a year in a keychain format. If you lose your keys in the morning, simply use the app on your phone to find the keychain. If you lose your phone simply get out your second phone.

This planned obsolescence didn’t jive with [JM] when his Tile stopped being discoverable. He didn’t want to toss a gadget that had served him so well into the landfill. So, like any good hacker, he cracked its plastic case open.

The Tile itself is a really interesting product. The largest component is the battery which has tabs spot-welded to its surface. Attached to those is a well laid out board. [JM] points out the clever use of spring contacts to engage the piezo element for the speaker as a nice example of good design for manufacture.

The hack itself was pretty easy to complete. Some electrical tape and soldering was all it took to embed the tile into the remote. Now he can take out his phone and press a button to hear a forlorn beep coming from under the couch cushions.

Reverse Engineer Your Robot Lawnmower

May 4, 2016 by Elliot Williams 21 Comments

Your home is your castle, and you are king or queen of all you survey. You’ve built your own home-automation system from scratch. Why would you possibly settle for the stock firmware in your robotic lawnmower? [Daniel Wiegert] wouldn’t either, so in Project Landlord he has started to reverse-engineer it.

You can hardly blame him. The Worx Landroid‘s controller board uses an NXP LPC1768 ARM Cortex-M3, and the debug pins are labelled on the backside. The manufacturer didn’t protect the flash memory. It’s just begging to have its firmware dumped. So far, [Daniel] has managed to both brick and unbrick the device, and has completely mapped the controller’s pinout, so he’s on his way to complete control.

Right now, he’s got a working proof-of-concept firmware on his GitHub that’s able to drive the machine around a little bit and set the brakes. It’s running FreeRTOS, and [Daniel] is looking for other people to get in on the project. He’s done the hard initial work, so get in there and reap the rewards! Just don’t neglect to remove the blade before custom firmware.

Will custom firmware in a robotic lawnmower change the world? Probably not. But it is awesome, and will certainly make a difference in the lives of people whose robot mowers continually get stuck behind the hydrangeas.

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Carbon Monoxide: Hunting A Silent Killer

May 4, 2016 by Adam Fabio 101 Comments

Walt and Molly Weber had just finished several long weeks of work. He was an FBI agent on an important case. She had a management job at Houghton Mifflin. On a sunny Friday evening in February of 1995, the two embarked on a much needed weekend skiing getaway. They drove five hours to the Sierra Mountains in California’s Mammoth Lakes ski area. This was a last-minute trip, so most of the nicer hotels were booked. The tired couple checked in at a lower cost motel at around 11:30pm on Friday night. They quickly settled in and went to bed, planning for an early start with a 7am wakeup call Saturday morning.

When the front desk called on Saturday, no one answered the phone. The desk manager figured they had gotten an early start and were already on the slopes. Sunday was the same. It wasn’t until a maid went to check on the room that the couple were found to be still in bed, unresponsive.

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