Hacking Cheap Chinese PID Temperature Controllers

July 26, 2015 by Nava Whiteford 26 Comments

[Harvs] hacked a cheap PID controller he found on eBay to improve its performance. The controller originally used a K-type thermocouple but lacked cold junction compensation. As thermocouples only provide a differential measurement between the measurement junction and cold junction, this meant the controller was assuming the cold junction was at room temperature, and would in many cases be significantly inaccurate. The system also used a no-name brand Chinese microcontroller making firmware hacks impractical.

[Harvs] decided that even with cold junction compensation a K-type thermocouple wasn’t ideal for his application anyway, and designed a replacement PCB to interface to the display and power supply. The new PCB is based around a Cypress PsoC (a popular choice for its great analog functionality) with a DS18B20 temperature sensor. At the lower temperature ranges [Harvs] is interested in the DS18B20 is far more accurate and easy to use than the thermocouple.

Though the project hasn’t been updated recently, [Harvs] was planning on adding an ESP8266 for remote monitoring and control. Great work [Harvs]!

Thanks to Peter for the tip.

Hackaday Prize Entry: Smart Low Voltage Lighting

July 25, 2015 by Brian Benchoff 14 Comments

A common theme around Internet of Things things is connecting a relay to the web. It’s useful for everything from turning on a lamp from across the country to making sure your refrigerator is still running without the twice-hourly calls from the International Refrigeration Commission. For his Hackaday Prize project, [Matt] is turning lights on and off with an ESP8266 WiFi module, but not just any lights: he’s focusing on low-voltage lighting with the ESPLux.

Most downlights and landscape lights run off a 12 or 24 V transformer, and because [Matt] wanted to add dimming to his lighting box, he’s rectifying the low voltage AC to DC; PWMing an output to light an LED is a much better idea than chopping AC with a triac.

With a rectifier, MOSFET, and an ESP8266, the ESPLux is a simple build, but the project doesn’t end with electronics. for automation and control of these lights, [Matt] is turning to OpenHAB, automation software that works with everything you would ever use to make your home smart.

The 2015 Hackaday Prize is sponsored by:

Alarm Notifies The Office When The Coffee Is Ready

July 24, 2015 by Rick Osgood 12 Comments

[Stian] thought it would be nice if his coworkers could be electronically notified when the latest batch of coffee is ready. He ended up building an inexpensive coffee alarm system to do exactly that. When the coffee is done, the brewer can press a giant button to notify the rest of the office that it’s time for a cuppa joe.

[Stian’s] first project requirement was to activate the system using a big physical button. He chose a button from Sparkfun, although he ended up modifying it to better suit his needs. The original button came with a single LED built-in. This wasn’t enough for [Stian], so he added two more LEDs. All three LEDs are driven by a ULN2003A NPN transistor array. Now he can flash them in sequence to make a simple animation.

This momentary push button supplies power to a ESP8266 microcontroller using a soft latch power switch. When the momentary switch is pressed, it supplies power to the latch. The latch then powers up the main circuit and continues supplying power even when the push button is released. The reason for this power trickery is to conserve power from the 18650 li-on battery.

The core functionality of the alarm uses a combination of physical hardware and two cloud-based services. The ESP8266 was chosen because it includes a built-in WiFi chip and it only costs five dollars. The microcontroller is configured to connect to the WiFi network with the push of a button. The device also monitors the giant alarm button.

When the button is pressed, it sends an HTTP request to a custom clojure app running on a cloud service called Heroku. The clojure app then stores brewing information in a database and sends a notification to the Slack cloud service. Slack is a sort of project management app that allows multiple users to work on projects and communicate easier over the internet. [Stian] has tapped into it in order to send the actual text notification to his coworkers to let them know that the coffee is ready. Be sure to watch the demo video below. Continue reading “Alarm Notifies The Office When The Coffee Is Ready” →

The Internet Of Soldering Irons

July 19, 2015 by Al Williams 25 Comments

The Internet of Things needs — well — things. Do you really need your paper shredder hooked up to the Internet? Maybe. But [Vegard Paulsen] put something on the network that every hacker can relate to: his soldering iron.

In typical hacker fashion, fixing a broken digital display on the soldering station turned into a development project that allows [Vegard] to monitor the temperature of his soldering iron on his phone. He found a handy source of power on the station’s PC board and connected a NodeMCU WiFi device (that uses the ubiquitous ESP8266 and an onboard Lua interpreter).

The data pushes out to the Thingspeak server which handles pushing data out to the bigger network, and data representation (like the cool Google gauge in the picture). The best part: [Vegard] gets a phone notification when he accidentally leaves his soldering iron on. How perfect is that?

One unique challenge he faced was soldering the power wires to the soldering station. This could be a problem because the iron tip is grounded so making the joint while the iron was energized would probably blow a fuse (or worse). Luckily, [Vegard] thought ahead and devised a plan that apparently worked.

We’ve seen other examples of how easy NodeMCU and Thingspeak work to put the mundane on the Internet. It seems particularly appropriate to hack a soldering iron, though.

Hackaday Prize Entry: Controlling Relays Over WiFi

July 4, 2015 by Brian Benchoff 1 Comment

It’s been less than a year since the ESP8266 WiFi Module was released. This is a chip whose original data sheets were only available in Chinese, could only be controlled through AT commands, and was (originally) only sold through Seeed Studio and other various Chinese retailers. It had one thing going for it: it was five dollars. For the price of a crappy sub, you can blink an LED from the Internet. Needless to say, the ESP8266 is now very popular.

There are a lot of ESP8266 projects in The Hackaday Prize this year, and [David]’s project is making great use of the relatively meager pinout of this module. He’s built an 8-channel relay controller with a WiFi interface to control industrial equipment. It’s a great project, but just of many ESP projects in the prize this year.

The ESP doesn’t have a huge number of pins, but there are enough for some serious work with the right hardware. He’s using the ESP-12 module to get the most pins, and using an SPI port expander to drive an octet of relays. It’s a simple board, but everything you need to control a bunch of relays over WiFi is right there: LEDs, reset buttons, and RS232 level conversion.

You can check out a pair of very satisfying videos of relays clicking below.

The 2015 Hackaday Prize is sponsored by:

Continue reading “Hackaday Prize Entry: Controlling Relays Over WiFi” →

Wirelessly Weighing Plants With The ESP8266

June 28, 2015 by Eric Evenchick 17 Comments

There’s a good number of hacks, and commercial products, for telling you when a plant needs watering. Most of them use an ADC to measure the resistance in the soil. As the soil’s moisture content drops, the resistance increases. High impedance, dead plant.

[squix]’s Thirsdee takes a different approach to plant health monitoring. Instead of measuring resistance, it simply weighs the plant. As the soil dries up, it gets lighter. By measuring the change in weight, the amount of water in the pot can be estimated.

Thirsdee uses a load cell to measure the weight. It’s read using an HX711 ADC, which is controlled by a NodeMCU. This development board is based on the ESP8266 chip. Since Thirsdee has WiFi, it can push notifications to your phone and log data on ThingSpeak. If you’re looking at the plant, an OLED shows you the current status of the plant. For us viewing from home, we can see a graph of [squix]’s plant drying out in real time.

[squix] provides us with a list of suppliers for the parts, and all the source code on Github.

Tracking Bitcoin With The ESP8266

June 18, 2015 by Brian Benchoff 15 Comments

[Kendrick] was looking for something to do with an ESP8266 WiFi module, and since he loves Bitcoin and Arduino, the obvious solution was to make a Bitcoin price tracker.

The ESP8266 is a complete microcontroller with a WiFi chip and a few pins for a serial connection. It’s certainly possible to write some firmware for the ESP to get the current conversion rate of Bitcoin, but for simplicity’s sake, [Kendrick] chose to use an Arduino for this project. He’s using a 5V Arduino, and the ESP operates on 3.3V logic, but a few Zeners take care of the logic level conversion.

The code running on the Arduino checks the CoinDesk API minute, parses the JSON coming from the API, and prints the current Bitcoin price to the serial port. For tracking the current conversion rate of Bitcoin, it’s vastly overkill. This project could have a few interesting applications, from hooking up a few seven-segment displays, to an RGB LED mood lamp that keeps track of this magic Internet money.