MUNICH — At Electronica last week, the LED manufacturer Everlight introduced what it claims to be the world’s first colour-temperature tunable LEDs in a simple chip on board (COB) package.
After brightness dimming, tunable color temperature is a feature that allows end users to tune the warmth of the light they receive. Typically, this feature is implemented through the use of multiple LEDs binned from cool white to warm white, behind a diffuser.
With its CHI3030 27V/29W series, Everlight claims to have a very compact solution, with LEDs packaged behind concentric layers of phosphors offering different color temperatures of white. Depending on how much warm white or cool white you choose to light up, you can get a precise color-temperature mix.
New LEDs offer tunable color temperature - [Link]
by Michael Mayes @ edn.com:
Although temperature is a fundamental aspect of our lives, it is difficult to measure accurately. Before the era of modern electronics, Galileo invented a rudimentary thermometer capable of detecting temperature changes. Two hundred years later, Seebeck discovered the thermocouple, a device capable of generating a voltage as a function of temperature gradients in dissimilar metals. Today, thermocouples as well as temperature dependent resistance elements (RTDs and thermistors) and semiconductor elements (diodes) are commonly used to electrically measure temperature. While methods for extracting temperature from these elements are well known, accurately measuring temperatures to better than 0.5ºC or 0.1ºC accuracy is challenging (see Figure 1).
Temperature-to-Bits converter helps solve challenges in sensor measurement - [Link]
I work as a software developer for a biology lab where my day job consists of creating applications to deal with big data visualisation. Recently however one of my colleagues had the need to take regular temperature measurements form a range of jars of liquids over quite an extended period. The commercial available solutions to achieve this are expensive and surprisingly lacking in features. So, as a dedicated hacker and maker, I immediately stepped in an said we could make something better ourselves. So we did. And this is how.
Quick & Easy Temperature Loggers - [Link]
by noelportugal @ instructables.com:
The day I read that a new $5 wifi module was available, I order a few of them to test. Now, a few weeks later I want to share my experience.
This is a very simple demo using the ESP8266 and Arduino to update a remote server (https://thingspeak.com/) using a digital temperature sensor.
ESP8266 Wifi Temperature Logger - [Link]
The LTC2983 measures a wide variety of temperature sensors and digitally outputs the result, in °C or °F, with 0.1°C accuracy and 0.001°C resolution. The LTC2983 can measure the temperature of virtually all standard (type B, E, J, K, N, S, R, T) or custom thermocouples, automatically compensate for cold junction temperatures and linearize the results. The device can also measure temperature with standard 2-, 3-, or 4-wire RTDs, thermistors, and diodes. It has 20 reconfigurable analog inputs enabling many sensor connections and configuration options. The LTC2983 includes excitation current sources and fault detection circuitry appropriate for each type of temperature sensor. The LTC2983 allows direct interfacing to ground referenced sensors without the need for level shifters, negative supply voltages, or external amplifiers. All signals are buffered and simultaneously digitized with three high accuracy, 24-bit ΔΣ ADC’s, driven by an internal 10ppm/°C (maximum) reference.
LTC2983 – Multi-Sensor High Accuracy Digital Temperature Measurement System - [Link]
RTC or real-time clock is a kind of computer clock for keeping track of the recent or most current time. Commonly, RTCs are present in almost all or any device, which are electronic in nature that needs to keep time accurate. Meanwhile, temperature sensors are devices that gather data concerning the temperature from a source and convert it to a form that can be understood either by an observer or another device. These sensors can be in various forms and are used for a wide variety of purposes, from simple home use to extremely accurate and precise scientific use. They play a very important role almost everywhere that they are applied; knowing the temperature helps people to pick their clothing before a walk outside just as it helps chemists to understand the data collected from a complex chemical reaction.
The circuit uses a PCA8565 CMOS real time clock and calendar optimized for low power consumption. A programmable clock output, interrupt output and voltage-low detector are also provided. All address and data are transferred serially via a two-line bidirectional I2C-bus with a maximum bus speed of 400kbit/s. The built-in word address register is incremented automatically after each written or read data byte. It also includes a MCP9801 digital temperature sensor capable of reading temperatures from -55°C to +125°C. Temperature data is measured from an integrated temperature sensor and converted to digital word with a user selectable 9 to 12 bit Sigma Delta Analog to Digital Converter. The MCP9801 notifies the host controller when the ambient temperature exceeds a user programmed set point. The ALERT output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupts. Communication with the sensor is accomplished via a two-wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the set point and hysteresis and configuring the device. Address selection inputs allow up to eight MCP9801 sensors to share the same two-wire bus for multizone monitoring. Small physical size, low installed cost and ease of use make the MCP9801 an ideal choice for implementing sophisticated temperature system management schemes in a variety of applications.
The board is basically a carrier for the two IC’s that make up the Real Time Clock (RTC), PCA8565 and the Digital Temperature Sensor, MCP9801. It conveniently combines the two for applications that require RTC and temperature sensing. A particularly useful feature of this RTC is that it can detect power down and record the time at that event. This is ideal for connecting to a microcontroller that does not have an RTC.
I2C Temperature Sensor & Real Time Clock - [Link]
Linear Technology Corporation has announced the LTC2983 high performance digital temperature measurement IC. The IC is a single chip solution to temperature sensor interfacing; it has 20 input channels for sensor connection and each input can be assigned the characteristics appropriate to the sensor used. This includes 8 standard thermocouple types, 8 RTDs, 8 thermister profiles and an external diode; if you are using a custom sensor you can also specify a custom table.
In addition to the impressive sensor capability the IC measures temperature with an accuracy of 0.1°C and a resolution of 0.001°C. The LTC2983 allows direct interfacing to ground referenced sensors without the need for level shifters, negative supply voltages, or external amplifiers. All signals are buffered and simultaneously digitized with three high-accuracy, 24-bit ΔΣ ADC’s, driven by an internal 10 ppm/°C (maximum) reference.
High Accuracy Universal Temperature Sensor IC - [Link]
by df99 @ instructables.com:
This is an OLED clock I built using an Arduino Micro, a tiny OLED 128×64 display using the SSD1306 controller and I2C interface, and a precision DS3231-based real-time clock module with rechargeable battery backup. It features a menu system for setting the RTC (no serial port or USB required)
DS3231 OLED clock with 2-button menu setting and temperature display - [Link]
by willseph @ imgur.com:
The web interface allows me to change the settings on my thermostat remotely, such as the set temperature range compressor and fan modes, as well as view any warning messages that may be reported.
It’s not exactly beautiful, but I’m a function-over-fashion person. The Raspberry Pi is in the middle, white power cable running down and a GPIO rainbow ribbon cord heading up to the relay module under the real thermostat.
Homemade Raspberry Pi smart thermostat - [Link]