This design is a basic temperature control for refrigerators that has an electromechanical circuit. It specifically uses MC9RS08KA4CWJR microcontroller which has an 8-bit RS08 central processing unit, 254 bytes RAM, 8Kbytes flash, two 8-bit modulo timers, 2-channel 16-bit Timer/PWM, inter-integrated circuit BUS module, keyboard interrupt, and analog comparator. This project effectively controls temperature of any device using resistors and capacitors.
The refrigerator temperature control is a basic RC network connected to an I/O pin. A variable resistor (potentiometer) is used to modify the time the capacitor takes to reach VIH and adjusting its resistance varies that time. A basic voltage divider with one resistor and one thermistor is used to implement the temperature sensor. The thermistor resistance depends on the temperature. For each temperature, we have a different voltage in the divider. This value is effectively measured with the Analog-to-Digital Converter (ADC) implemented by software that uses one resistor, one capacitor, and the analog comparator. In addition, VDD and VSS are the primary power supply pins for the MCU. This voltage source supplies power to all I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides a regulated lower-voltage source to the CPU and other MCU internal circuitry.
This temperature control will not only be applicable to refrigerators but also to electronic devices that need temperature monitoring. It is a low cost device that may be integrated to appliances, medical and industrial equipment.
Basic Temperature Control for Refrigerators – [Link]
by gulliverrr @ instructables.com:
Okay, there are too many open source home automations out there but whenever I tried to look into making any of these I ended up with a bitter taste because of one or a few of the following reasons:
The software part was open but the hardware was based on boards either too complicated to produce myself economically or simply proprietary that I could only buy ready
The sensors/parts were too expensive
It was too ugly for my living room
HestiaPi – Open Smart Thermostat – [Link]
Proportional-Integral-Derivative (PID) control is the most common control algorithm used in industry and has been universally accepted in industrial control. The popularity of PID controllers can be attributed partly to their robust performance in a wide range of operating conditions and partly to their functional simplicity, which allows engineers to operate them in a simple, straightforward manner.
As the name suggests, PID algorithm consists of three basic coefficients; proportional, integral and derivative which are varied to get optimal response. Closed loop systems, the theory of classical PID and the effects of tuning a closed loop control system are discussed in this paper. The PID toolset in LabVIEW and the ease of use of these VIs is also discussed.
PID Theory Explained – [Link]
Nuimo is a universal controller for the internet of things. Control your music, lights, locks and more.
Nuimo is an intuitive and natural way to interact with your connected devices. Nuimo works with any bluetooth device or application including Sonos and Philips Hue.
Nuimo is a freely programmable controller and wireless so you can take it anywhere. Using the nuimo you can control all of your devices through our simple and seamless physical controller.
Unlike the touch screen, nuimo has a number of touch based inputs that feel familiar and suit your needs. It incorporates capacitive touch, gesture recognition and a 360 degree analog ring that gives you precise control over everything from the volume of your music to switching off your lights. These inputs are easily mappable to the devices and applications you care about most.
Nuimo: Seamless Smart Home Interface – [Link]
The IEEE 802.15.4 standard is the fourth task group of the IEEE 802.15 working group, which defines Wireless Personal Area Network (WPAN) standards. The IEEE 802.15.4 market has the following advantages; low power consumption, low cost, low offered message throughput, supports large network orders up to 65k nodes, low to no QoS guarantees, and flexible protocol design suitable for many applications. The purpose for this standard is to empower simple devices with a reliable, robust wireless technology that could last for years on standard primary batteries. It is designed to allow developers to effectively use and benefit from radios based upon the standard.
This reference design is a low cost System-on-Chip (SoC) solution for the IEEE 802.15.4 standard that incorporates a complete, low power, 2.4GHz radio frequency transceiver with TX/RX switch, an 8-bit HCS08 CPU, and a functional set of MCU peripherals into a 48-pin LGA package. This product targets wireless RF remote control and other cost-sensitive applications ranging from home TV and entertainment systems to medical and supports all ZigBee node types. The Freescale’s MC13237 is a highly integrated solution, with very low power consumption. The MC13237 contains an RF transceiver that is an 802.15.4 standard 2006 compliant radio that operates in the 2.4GHz ISM frequency band. The transceiver includes a low noise amplifier, 1mW nominal output Power Amplifier (PA), internal Voltage Controlled Oscillator (VCO), integrated transmit/receive switch, on-board power supply regulation, 12-bit ADC and full spread-spectrum encoding and decoding.
This design is not only limited for remote controls. It can also be used as the basis for wireless devices and other sensor-controlled application that used IEEE 802.15.4 standard. The IEEE 802.15.4 radios have the potential to be the cost-effective communications backbone for simple sensory mesh networks that can effectively carry data with relatively low latency, high accuracy, and the ability to survive for a very long time on small primary batteries.
SoC Remote Control Platform for IEEE 802.15.4 Standard – [Link]
An industrial plant is designed with different control systems in which it varies according to the equipment to be controlled. This design is a general-purpose engine control system, which handles fueled or electrically supplied small engines of industrial plant. It features a 1.0A power relay control, 2.0A relay for fuel pump control, and a lamp driver. The system is also capable of start-up/shut-down control with power sequence logic. It has independent fault protection against surges and possible fluctuations.
The design is comprised of a MC33814 engine control analog power IC, a USB to SPI dongle interface, and power conditioning circuitry. It drives the engine electrically or fueled through relays. It also drives the fuel injector that runs the equipment during fueled operation. All 5V VCC power required by the circuit is obtained from the MC33814 built-in power regulator. A 12V VBAT supply provides the power to the three internal voltage regulators. A PC communicates to this project through a USB/SPI dongle (KITUSBSPIDGLEVME) connected to the PC’s USB port. The Freescale SPIGen program provides the user interface to the MC33814 SPI port and allows the user to send commands to the IC and receive status from the IC.
This project is designed to drive several industrial engine functions, a set of screw terminals are designated for control outputs: tachometer output, lamp output, water heater output, two relay outputs, two injector outputs, and two ignition outputs. This kind of control system is very useful in machineries that are usually used in industrial plants for the convenience of the plant operators.
Industrial Small Engine Control – [Link]
sparkybg shared his universal soldering controller:
The intention was to build the most universal soldering controller I can think of. It can drive any low voltage (upto 24V) iron with thermocouple or resistive sensor, in series with the heater, or separate.
Here is a short list of features:
– power: 9-28V, AC or DC
– 2 separate heater control channels
– 2 independent sensor inputs
– current source on any sensor input 3uA – 12mA, wuth 2 bands (x1, x16) and 256 steps per band
– flexible differential amplifier input selection
– amplifier gain from 0 to 750 in 256 steps
– negative offset selection in 1024 steps
– resistive instrument identification (upto 625 different instruments can be identified by 2 resistors on the connector)
– polynomial floating point voltage/resistance to temperature calculation
– wave shaping to filter out the inductive peaks from series sensor signal
– PID control with power limit
– isolated USB port for firmware updates and live data
– 128×64 OLED display with rich user interface.
Universal soldering controller – [Link]
This is an WIFI-based appliance module using the ESP8266 (ESP12) and a latching relay. The appliance module is powered from the AC line using an inexpensive 5V 1AMP universal input power supply which is attached to the board. There are provisions for local control using a pushbutton switch, and there is an option for a WIFI status LED. The firmware is written in C and the appliance module is controlled using MQTT and JSON.
WIFI based appliance module using the ESP8266 and a latching relay – [Link]
Buzz..Buzzzz..buzzzzzzzz .. That is how a lone mosquito irritates you in the middle of the night trying to convince you that his lullaby is helpful. Insignificant or not, But truly that is the underlying inspiration for this project. The Mosquito repellents have this obnoxious smell that I would not like to sleep in and these loner mosquitoes who just piss me off by buzzing in the ear, you have to choose a lesser evil. Obviously, I turned ON the repellent and in a while it goes off but the smell starts building up and I am too lazy to turn it back OFF, leaving the warmed blanket on a chilly Delhi December Night. The nocturnal dilemma .
RoomMote – Control the color and sockets of your Room – [Link]
This device is a home automation lighting solution based on the presence of a person inside the room. When a person enters or leaves the room, the circuit automatically turns the lights of a room ON and OFF respectively. It also has a memory element which eliminates undesired switching of the lights in the event of more than one person entering or leaving the room
Home Automation Lighting Control – [Link]