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.

File Sharing In Your Pocket

The idea of a pirate box is pretty simple. All you need is a tiny Linux system with a WiFi adapter, a bit of storage space, and the software that will allow anyone to upload a few files to the server and an interface that will let anyone on the network download those files. In practice, though, a pirate box is a mess of wires and power adapters – not the pocketable device a WiFi file sharing box should be.

[Chris] came up with a much smaller file sharing beacon. It’s not based on a router; instead, [Chris]’ build uses an ez Share WiFi microSD adapter. It’s a device meant to push pics taken by a digital camera up to the Internet, but by configuring the software just so, up to five users can connect to the adapter and pull files down from a microSD card. The build only requires putting power to the correct pins. A LiPo battery and charge controller takes care of this problem.

There are a few shortcomings to this project – [Chris] doesn’t know how to upload files to the device. Maybe someone sufficiently clever can figure out how to make that work. Still, if you’re ever in a situation where you’d like to share some files with people in the same building, this is the device you need.

Thanks [Jake] for the tip.

Wearable WiFi Finder Uses the ESP8266

It seems like a day doesn’t go by without an ESP8266 project here on Hackaday. There’s a good reason for that, the chip and associated modules have brought low-cost WiFi connectivity to the masses. Today we have [Stevica Kuharski], who has built an open WiFi access point detector using the ESP8266. To do this he’s using the Lua compatible NodeMcu firwmare. [Stevica] wrote his own Lua scripts to run on the ESP8266’s internal 32 bit microcontroller. The freewifi script scans and searches for open WiFi networks. If a network is detected, the user is informed via a blinking LED.

To make the project wearable, [Stevica] powered the project with a pair of CR2450 coin cell batteries. The ESP8266 is not known for being a particularly low power device, so we’re curious to see what sort of battery life  [Stevica] gets with his project. The project source is already available on GitHub, and [Stevica] is hoping to kick off an Indiegogo campaign in the next few weeks. Click past the break to see the WiFi detector in action.

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SNES Controller Modified to be Completely Wireless

[Pat] was looking for a way to wirelessly control his Fire TV unit. He could have just went with one of many possible consumer products, but he decided to take it a step further. He modified a unit to fit inside of an original SNES controller. All of the buttons are functional, and the controller even features a wireless charger.

[Pat] started out with a Bluetooth video game controller marketed more playing video games on tablets. The original controller looked sort of like an XBox controller in shape. [Pat] tore this controller open and managed to stuff the guts into an original SNES controller. He didn’t even have to remove the original SNES PCB. [Pat] mentions that it was rather tedious to rewire all of the buttons from the original controller, but in the end it wasn’t too difficult. The only externally visible modification to the original controller is a small hole that was made for a power button.

In order to make this unit completely wireless, [Pat] also installed a Qi wireless charging module. Now, placing the controller on a charging pad will charge up the small LiPo battery in just about 45 minutes. This controller would be the perfect addition to a RetroPi or other similar project. If you’re not into Bluetooth, you can try using a Logitech receiver instead. Continue reading “SNES Controller Modified to be Completely Wireless”

Great Scott! A Flux Capacitor Notification Light

If you are into your social media, then you probably like to stay updated with your notifications. [Gamaral] feels this way but he wasn’t happy with the standard way of checking the website or waiting for his phone to alert him. He wanted something a little more flashy. Something like a flux capacitor notification light. This device won’t send his messages back in time, but it does look cool.

He started with an off-the-shelf flux capacitor USB charger. Normally this device just looks cool when charging your USB devices. [Gamaral] wanted to give himself more control of it. He started by opening up the case and replacing a single surface mount resistor. The replacement component is actually a 3.3V regulator that happens to be a similar form factor as the original resistor. This regulator can now provide steady power to the device itself, as well as a ESP8266 module.

The ESP8266 module has built-in WiFi capabilities for a low price. The board itself is also quite small, making it suitable for this project. [Gamaral] used just two GPIO pins. The first one toggles the flux circuit on and off, and the second keeps track of the current state of the circuit. To actually trigger the change, [gamaral] just connects to the module via TCP and issues a “TIME CIRCUIT ON/OFF” command. The simplicity makes the unit more versatile because an application running on a PC can actually track various social media and flash the unit accordingly.

Wireless Water Level Sensor from PVC Pipe

[Bob] was having trouble keeping up with his water troughs. He had to constantly check them to make sure they weren’t empty, and he always found that the water level was lower than he thought. He decided it was time to build his own solution to this problem. What he ended up with was a water level sensor made from PVC pipe and a few other components.

The physical assembly is pretty simple. The whole structure is made from 1/2″ PVC pipe and fittings and is broken into four nearly identical sensor modules. The sensors have an electrode on either side. The electrodes are made from PVC end caps, sanded down flat at the tip. A hole is then drilled through the cap to accommodate a small machine screw. The screw threads are coated in joint compound before the screw is driven into the hole, creating its own threads. These caps are placed onto small sections of PVC pipe, which in turn connect to a four-way PVC cross connector. 

On the inside of the electrode cap, two washers are placed onto the screw. A stranded wire is placed between the washers and then clamped in place with a nut. All of the modules are connected together with a few inches of pipe. [Bob] measured this out so it would fit appropriately into his trough, but the measurements can easily be altered to fit just about any size container. The wires all route up through the pipe. The PVC pipe is cemented together to keep the water out. The joint compound prevents any leaks at the electrodes.

A piece of CAT 5 cable connects the electrodes to the electronics inside of the waterproof controller box. The electronics are simple. It’s just a simple piece of perfboard with an XBee and a few transistors. The XBee can detect the water level by testing for a closed circuit between the two electrodes of any sensor module. The water acts as a sort of switch that closes the circuit. When the water gets too low, the circuit opens and [Bob] knows that the water level has lowered. The XBee is connected to a directional 2.4GHz antenna to ensure the signal reaches the laptop several acres away. Continue reading “Wireless Water Level Sensor from PVC Pipe”

A Wireless Web-Connected Morse Code Keyer

[Kevin] recently scored a Morse code keyer/sounder unit from the 1920s on eBay. While many hams would love to use an old keyer for CW, [Kevin] took a different route and repurposed it into a wireless web-connected morse code keyer.

[Kevin] mounted an Arduino Yun under the keyer, which listens for user input and provides web connectivity. The Yun connects to [Kevin]’s open-source web API he calls “morsel,” which allows it to send and receive messages with other morsel users. When a message is keyed in, the Yun publishes it to the API. When another keyer queries the API for incoming messages, the Yun downloads the morse sequence and replays it on the sounder.

[Kevin] also added some copper electrodes to the top of his enclosure, which act as capacitive buttons while keeping the keyer’s old-school appearance. The left button replays the most recently received message, and the right button sets the playback speed. Check out the video after the break to hear and see the keyer in action.

Thanks for the tip,  [Jarrod].

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