Dumbing Down a Smart Switch

Internet of Everything is the way to go for home automation these days. ITEAD makes an ESP-8266 switch that IoT-ifies your appliances. If you still have an ancient, 433 MHz style radio switch system, they even make one that does WiFi and 433 MHz. But if you’re too cheap to shell out for the dual-mode version, you can always add a $1 433 MHz radio yourself. Or at least, that’s what [Tinkerman] did.

IMG_20160522_163814x_thumbnailAside from the teardown and reverse-engineering of the WiFi-enabled switch, [Tinkerman] also flashed custom firmware into the switch’s ESP-8266, and worked it all into his existing home Node-RED framework. Now he’s got more possible ways to turn on his living-room lights than any person could possibly hope for!

If you want to get into this whole WiFi-based home automation game, you could do worse than to have a look at the series we ran on MQTT just a little while ago. Seeing [Tinkerman]’s Node-RED demo makes us think that we’ll have to give that a look for our home system as well.

Easy DIY Telemetry Goes the Distance

[Paweł Spychalski] wrote in to tell us about some experiments he’s been doing, using cheap 433 MHz HC-12 radio units as a telemetry radio for his quadcopter.

In this blog post, he goes over the simple AT command set, and some of the limitations of the HC-12 part. Then he takes it out for a spin on his quadcopter, and finds out that his setup is good for 450 meters in an open field. Finally, he ties the radio into his quad’s telemetry system and tethers the other end to his cellphone through a Bluetooth unit for a sweet end-to-end system that only set him back around $20 and works as far out as 700 meters.

The secrets to [Paweł]’s success seem to be some hand-made antennas and keeping the baud rate down to a reasonable 9600 baud. We wonder if there’s room (or reason?) for improvement using a directional antenna on the ground. What say you, Hackaday Antenna Jockeys?

Also check out this very similar build where an ESP8266 replaces the Bluetooth module. And stashes it all inside a nice wooden box! Nice work all around.

Minimal 433 MHz Web Home Automation

How minimal can a decent home automation setup be? If you need an HTML frontend, you’re going to need a webserver. An ESP8266 will do the trick. And then you need to be able to control your electronics. The cheapest and easiest way to do that is with the ubiquitous 433 MHz remote-controlled outlets and a $1 radio unit from an online auction site. Add in a cheap ESP8266 module, and your total outlay is going to be under $20.

That’s exactly what [Nikos Kantarakias] did. He combined a bunch of available ESP8266 Arduino libraries — one for driving the 433 MHz radio modules, [Paul Stoffregen]’s libraries for keeping time and for setting alarms, and another for keeping track of time zones — with some of his own code for setting up WiFi access, and it’s done.

It’s all available on GitHub for your perusal. The code does some strange things — like requiring a complete reboot every time you set an alarm — but it does let you set recurring and one-off activations of the attached devices with a web interface that’s served off the ESP8266 itself. If you want your coffee machine to turn itself on in the mornings, and want a system that’s easy for the other inhabitants of your house to configure, something like this might be just the ticket.

But if you’re looking for a project on the other end of the ESP-tech spectrum, [CNLohr] wrote a standalone Ethernet controller for the thing. Woah.

Reverse Engineering Wireless Temperature Probes

[bhunting] lives right up against the Rockies, and for a while he’s wanted to measure the temperature variations against the inside of his house against the temperature swings outside. The sensible way to do this would be to put a few wireless temperature-logging probes around the house, and log all that data with a computer. A temperature sensor, microcontroller, wireless module, battery, case, and miscellaneous parts meant each node in the sensor grid would cost about $10. The other day, [bhunting] came across the exact same thing in the clearance bin of Walmart – $10 for a wireless temperature sensor, and the only thing he would have to do is reverse engineer the protocol.

These wireless temperature sensors are exactly what you would expect for a cheap piece of Chinese electronics found in the clearance bin at Walmart. There’s a small radio operating at 433MHz, a temperature sensor, and a microcontroller under a blob of epoxy. The microcontroller and transmitter board in the temperature sensor were only attached by a ribbon cable, and each of the lines were labeled. After finding power and ground, [bhunting] took a scope to the wires that provided the data to the radio and took a look at it with a logic analyzer.

After a bit of work, [bhunting] was able to figure out how the temperature sensor sent data back to the base station, and with a bit of surgery to one of these base stations, he had a way to read the temperature data with an Arduino. From there, it’s just a data logging problem that’s easily solved with Excel, and [bhunting] has exactly what he originally wanted, thanks to a find in the Walmart clearance bin.

RFToy Makes Wireless Projects Easier

[Ray] has created RFToy, a simple gadget to aid in setting up wireless systems with a variety of common radio modules. RFToy is an open source microcontroller board running on an ATmega328. While RFToy is Arduino code compatible, [Ray] chose to ditch the familiar Arduino shield layout for one that makes it easier to install RF modules, and is more handheld friendly.

[RFToy] includes headers for the popular nRF24L01 2.4 GHz transceiver, as well as 433/315 transmitters and receivers found in many low-cost wireless electronic devices. The 128×64 pixel OLED screen and 3 button interface make it easy to set up simple user interfaces for testing new designs.

[Ray] hasn’t broken any new ground here. What he has done is create a simple tool for wireless projects. Anyone who’s worked on a wireless system can tell you that tools like this are invaluable for debugging why your circuit isn’t talking. Is it the transmitter? The receiver? Something else in the power supply circuit?

Check out [Ray’s] demo video after the break. In it, he sniffs, records, and plays back signals from several remote-controlled outlets. [Ray] also has a great demo of sending temperature data back and forth using an nRF24L01.

Continue reading “RFToy Makes Wireless Projects Easier”

Fail of the Week: Reverse Engineering a Wireless Energy Monitor


[Afonso] picked up a cheap energy use monitor a few years back. He really like the data it displays about his home’s electricity, using a sensor to gather this info and a display that communicates with it wirelessly. But there is no option to log or dump the data. He set out to reverse engineer the wireless protocol in order to extend the use of the system. As the name of this column implies, he failed to get this working.

The hardware above is a 433Mhz transceiver that he rigged up as test hardware. It sounds like he’s assuming the monitor works on this band, which could have been his first misstep (we really don’t know). The speaker is there to give audible confirmation that he’s receiving something from the transmitter. This is where things start to get pretty weird. White noise was coming from the speaker, but when he stepped away from the bench it stopped. He was able to measure a regular pattern to the noise, and proceeded to place the speaker next to his computer MIC so that he could record a sample for further analysis.

Fail of the Week always aims to be a positive experience. In this case we’d like to have a conversation about the process itself. We agree that connecting a speaker (or headphones) should help get your foot in the door because your ear will recognize a rhythmic pattern when it is received. But with this noise, measuring the timing and recording a sample we’re not so sure about. Given the situation, how would you have soldiered on for the best chance at successfully sniffing out the communication scheme used by this hardware? Leave a comment below!

2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Wireless microcontroller/PC interface for $3


Sending data from a microcontroller to a PC usually requires some sort of serial connection, either through fiddly on-chip USB, FTDI chips, or expensive radio ICs. [Scott] didn’t want to deal with this when creating a network of wireless temperature sensors, so he hacked up a few cheap 433 MHz radio transmitters and receivers to transmit data to a PC for about $3.

After sensor data is collected on a microcontroller and sent over radio, there’s still the issue of getting it into a PC. For this, [Scott] piped the data into the microphone port of a cheap USB sound card. We’ve seen this trick before both in the world of microcontrollers and loading programs onto a Commodore 64 via a cassette interface.

Once the data is sent into the sound card, it’s decoded with a a small Python app. Given the range and quality of the RF transmitters and receivers  [Scott] says it’s not an extremely reliable way to send data to a PC. It is cheap, though, and if you need to read sensors wirelessly on a budget, it’s hard to do much better.

Check out [Scott]’s demo of his creation below.