A simple temperature control system for 3D print or other constant temperature control purpose by Xiang:
I plan to build a home-made 3D printer controlled by my Raspberry Pi, which, unfortunately, does not have any analog data acquisition pin. Therefore I decide to build a stand-alone temperature control system.
The idea is very simple. I use a power resistor as the heater and a thermistor as the temperature sensor. The system contains an LM324 quad op-amps chip. One op-amp is used as a comparator to compare the thermistor resistance with a nominal resistance and output LOW or HIGH as the comparison result. The other three op-amps inside the LM324 are used to perform some linear transformation and output a voltage that is proportional to the thermistor temperature. This voltage is applied to a 0-30V voltmeter so one can read the temperature. A N-Channel MOSFET transistor is used to control on/off of the heater.
Simple temperature control system - [Link]
Clap switch/Sound-activated switch designed around op-amp, flip-flop and popular 555 IC. Switch avoids false triggering by using 2-clap sound. Clapping sound is received by a microphone, the microphone changes the sound wave to electrical wave which is further amplified by op-amp.
555 timer IC acts as mono-stable multi-vibrator then flip-flop changes the state of output relay on every two-clap sound. This can be used to turn ON/OFF lights and fans. Circuit activates upon two-clap sound and stays activated until another sound triggers the circuit.
Sound Activated Switch - [Link]
These are the RFID readers I used. http://www.parallax.com/product/32390
Arduino RFID Card Door Lock System - [Link]
Control physical devices using an Arduino based home automation controller that connects to your network and lets you switch things on and off using a web browser. This episode shows the construction sequence of a controller that combines an Arduino-compatible board, Power-over-Ethernet, and relay driver shields to create a self-contained controller that can serve up its own web interface so you can click buttons in your browser to turn devices on and off.
Building an Arduino home automation controller - [Link]
Diogoc shared his Hakko T12 soldering controller in the project log forum:
I finally finished my Hakko T12 soldering controller.
Thanks to sparkybg and arhi for all help and sugestions.
Some features of the controller:
– 3310 graphic display
– rotary encoder for easy and fast temperature selection
– sleep mode when the iron is in the stand
– turn off when a long time in sleep mode
– audible indications
– intuitive menu navegation
– percentage visualization of output power
– powered by a compact and lightweight 24V dc laptop power supply
– ambient temperature sensor for a better cold junction compensation
– lcd backlight control
– alarm for very high temperature, turning off immediately the heater
– indication of tip removed to allow hot swapping the tips
– bootloader for easy firmware upgrade via integrated usb port
– usb port and c# software to monitoring all parameters and help to adjust the pid parameters
The controller still need a little adjust in the PID parameters but for me it is almost perfect.
Hakko T12 soldering controller - [Link]
The Project works as electronic toggle switch. The circuit is based on CMOS CD4013 Flip Flop IC, The circuit has two stable states, ON and OFF. Once it is ON, it remains ON till you press the switch again. A short button press of a tactile switch SW1 latches the circuit ON and another toggles it back OFF. Relay switch contacts can handle high AC Voltage as well as High DC current, this makes the project suitable for application like ON/OFF Fan, Light, TV, Pump, DC Motor, any electronic project required electronic toggle operations and few other devices work on AC voltage up to 250V AC or DC current up to 5Amps.
Electronic Toggle Switch - [Link]
0xPIT @ github.com writes:
This Reflow Oven Controller relies on an Arduino Pro Micro, which is similar to the Leonardo and easily obtainable on eb*y for less than $10, plus my custom shield, which is actually more like a motherboard.
As I believe it is not wise to have a mess of wiring and tiny breakout-boards for operating mains powered equipment, I’ve decided to design custom board with easily obtainable components.
The hardware can be found in the folder hardware, including the Eagle schematics and PCB layout files. It should fit the freemium version of Eagle
Reflow Oven Controller with graphics TFT - [Link]
by brmarcum @ instructables.com:
I hate Christmas tree lights.
Well not really, I just don’t enjoy having to climb under the tree every time I want to plug in or unplug the lights. In the interest of saving my sanity, I decided to build a motion activated switch that can power the lights for me. It has an integrated adjustable timer so they will stay on for as long or as short as I want. Here’s a video showing the final test on the fish tank light.
Motion Activated AC Switch - [Link]
Jaanus Kalde made this 32 channel light dimmer project, that is available at Github:
I needed a computer controllable 32 channel light dimmer for an art installation. After looking around a bit I found out that there isn’t even a Arduino shield for the work. So I made a quick 4 channel stackable board to control lights. The board uses SHARP thyristor based solid state relays to switch mains voltage. As normal with thyristors – all the outputs can be used as dimmers through zero-crossing detection. All outputs are able to handle 0.9 A / 200 W. We connected 40 W incandescent light bulbs to it but you can control whatever with it – lights, electronics, computers, motors etc.
32 channel mains lamp controller - [Link]
Andrianakis Haris informed us about his latest project. It’s a digital Thermostat for energy saving fireplaces. He writes:
In the need of my new homemade energy saving fireplace (which boils water for the radiator) i designed and built a digital thermostat. The idea to design my own thermostat came when i came across with the following problem.
When i first fire the fireplace the water in the boiler around the fireplace is cool. After a few minutes the fireplace warms the water enough so that the water temp exceeds the thermostat limit. The thermostat changes state and drives an electric valve to move the water from the fireplace boiler to the radiators. The electric valve is slow enough and takes a few minutes to make a full turn. While the water is moving from the fireplace boiler to the radiators, circularly cool water is coming back in the fireplace boiler from the radiators. Τhe water temp in the fireplace boiler is getting cooler and after a few minutes falls under thermostat’s limit. The thermostat changes state and stops the valve from driving the water to radiators. This happens again and again until the whole amount of water in the radiators is get warm.
Thermostat V1.0 for energy saving fireplaces - [Link]