App note: SOLERIQ® L38

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OSRAM’s filament looking LED application note. Link here (PDF)

SOLERIQ® L38 (GW T3LxF1) is a filament LED with a beam angle of 360deg for indoor retrofit lighting applications. It combines the advantages of modern LED technology with the aesthetics of traditional light bulbs.

The construction of the SOLERIQ® L38 consists of a ceramic based frame with two alloy connectors at both ends. A number of highly efficient LED chips (depending on the lumen package) is mounted on the ceramic based frame and they are electrically connected through wire bonding, covered by a colored diffused silicone resin.

App note: Magnetometer placement in mobile devices

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Correct magnetometer placement app note from Kionix. Link here (PDF)

Electronic devices contain many parts which can affect a magnetic sensor. When deciding the mounting position, it is necessary to consider the types of materials and the amount of current carried in proximity of the magnetic sensor.

Accuracy of an electronic compass depends upon getting clean geomagnetic data from the magnetic sensor output without errors caused by other magnetic elements. These errors need to be canceled by calibration or correction. This document explains magnetometer integration challenges from the mobile equipment point of view, and gives guidelines for the mounting position of the magnetic sensor.

App note: Embedded orientation detection using the MMA8450Q

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NXP’s accelerometer chip MMA8450Q, provides orientation detection on handheld devices. Link here (PDF)

This application note targets the portrait/landscape orientation detection feature which has become standard in many hand-held electronic devices. Additionally, this application note aims to explain uses as well as highlight some of the challenges of designing an embedded algorithm into the sensor. Included in content, the embedded settings of the MMA8450Q are explained and detailed for implementation.

App note: Understanding linear resonant actuator characteristics

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Application note about Linear Resonant Actuators from Precision Microdrives. Link here

Linear Resonant Actuators (LRAs) are becoming more popular for haptic applications. They are an alternative to eccentric rotating mass vibration motors and have several distinct advantages. For example they have better haptic performance characteristics and are more efficient. For these reasons they are used in many handheld and touchscreen devices, amongst other applications.

App note: Implementing an I2C reset

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Interesting app note from Analog Devices when an I2C communication is broken under some circumstances. Link here (PDF)

The I2C bus is a high integrity, robust serial bus used for control purposes in many systems. The primary components that make up a system are at least one master and one slave. Under normal conditions, everything works fine; however, it is the abnormal conditions that generate problems. Two questions present themselves when a problem arises: Is the problem device or system related, or some combination of both? What, if anything, can be done about it?

Hard device failures are relatively easy to isolate. Perhaps a function does not work, proper power cycling does not resolve the issue, pins are stuck high or low, and so on. System related problems sometimes disguise themselves as device failures, or worse, are intermittent. It is the latter area that this application note examines because it represents the majority of bus fault conditions.

Frequently the master, which is usually a microcontroller or a gate array, will be interrupted in the middle of its communication with an I2C slave and, upon return, find a stuck bus. Initially this looks like a device problem, but it is not. The slave is still waiting to send the remainder of the data requested by the master. The problem is that the master has forgotten where it was when it was interrupted or reset.

App note: Environmental compensation on the AD7142: The effects of temperature and humidity on capacitance sensors

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An old but useful application from Analog Devices about things that can affect touch/capacitance sensors. Link here (PDF)

Capacitance sensing has the potential to replace current user input mechanisms in consumer devices. Products as diverse as cell phones, digital cameras, MP3 players, and other portable media players are all suitable for implementing capacitance sensing.

Capacitance sensing has many benefits. It gives the user an interface with greater sensitivity and control. Capacitance sensors are easy to manufacture and reliable, and have advantages over current mechanical interfaces. However, all types of capacitance sensors are affected by capacitance changes in the surrounding environment. Changes in humidity or temperature can interfere with the operation of the sensors, in some cases stopping the sensor from working altogether.

App note: Engineering scaling

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Scaling large values to be fed on limited input digital meters, application note from Murata. Link here (PDF)

It is oftentimes necessary to attenuate “large” input signals down to a level that more closely matches the input range of a selected meter. For example, suppose the signal to be measured is 19 Volts, and the input voltage range of the available meter is 2 Volts (the preferred model for any attenuation circuit). Obviously, the “raw” input signal voltage is much too high for a ± 2V meter to measure directly and must first be attenuated.

App note: General overview of IR transmission in free ambient

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Vishay’s general information about IR transmission in free ambient. Link here (PDF)

Free ambient IR data transmission, IR remote control as well as most opto-electronic sensors and light barrier systems work with an optical wavelength between 870 nm and 950 nm. The emitter and detector components are highly efficient in this near IR wavelength band and can be manufactured at low cost.
Data transmission in free space demands high interference immunity of the IR receiving modules. The receiver unit, waiting to receive signals, is bombarded with different optical and electromagnetic noise signals, which are omni-present in the ambient or generated by the electrical appliance itself. All optical sources with an emission spectrum in the reception bandwidth (830 nm to 1100 nm) of the detector can be considered as disturbance sources. These are mainly fluorescent lamps, incandescent lamps and sunlight. Many plasma displays can also produce significant emissions in the optical band of the IR transmission.

App note: Using Vishay infrared receivers in a Wi-Fi environment

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2.4Ghz and 5 Ghz Wi-fi signals can sometimes affect IR receivers, here’s Vishay’s app note about them. Link here (PDF)

In recent years, Wi-Fi connectivity has penetrated most consumer electronic devices used for media reproduction. New TVs, satellite receiver and cable boxes, and streaming devices are more often than not built with Wi-Fi capabilities at multiple frequencies: 2.4 GHz and 5 GHz. Most of these appliances continue to support an infrared (IR)-based remote control link, often even when the device also supports a newer RF-based remote control.
IR remote control receivers are built with highly sensitive wideband input stages and are able to detect signals near the noise level of their circuitry. In noisy environments, such as with both low- and high-frequency electromagnetic interference (EMI), the receiver may be noise-triggered, typically manifesting itself in the form of spurious pulses at its output. Most Vishay IR receiver packages are designed with metal shields to effectively guard the receiver against low-frequency EMI. However, these metal shields have not proven entirely satisfactory against high-frequency EMI in the GHz range used for Wi-Fi.