Tag Archives: wireless

LTC4123 – Low Power Wireless Charger

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Linear Technology Corporation introduces the LTC4123 to further expand its offerings in wireless battery charging. The LTC4123 combines a 30mW wireless receiver with a constant-current/constant-voltage linear charger for NiMH batteries, such as Varta’s power one ACCU plus series. An external resonant LC tank connected to the LTC4123 enables the IC to receive power wirelessly from an alternating magnetic field generated by a transmit coil.  Integrated power management circuitry converts the coupled AC current into the DC current required to charge the battery. Wireless charging with the LTC4123 allows for a completely sealed product and eliminates the need to constantly replace primary batteries. Zn-Air (Zinc-Air) detection allows applications to work interchangeably with both rechargeable NiMH batteries and primary Zn-Air batteries with the same application circuit. Both battery types can directly power a hearing aid ASIC without the need for additional voltage conversion. By contrast, a 3.7V Li-ion battery requires a step-down regulator in addition to the LTC4123’s functionality to power the ASIC.

LTC4123 – Low Power Wireless Charger – [Link]

 

The world’s tiniest temperature sensor is powered by radio waves

wireless batterijloze thermometer van PhD Hao Gao, vakgroep Mixed Signal Microelectronics, EE TU/e

Researchers at the Eindhoven University of Technology in the Netherlands have created what they call the tiniest temperature sensor that is powered by the same wireless network it uses to communicate data. The sensor measures 2 square millimeters and needs no physical connection to send data. The current version of the sensor has a range of 2.5 centimeters but this is something to be improved in future versions.

The sensor contains an antenna that captures the energy from the router. The sensor stores that energy and, once there is enough, the sensor switches on, measures the temperature and sends a signal to the router. This signal has a slightly distinctive frequency, depending on the temperature measured. The router can deduce the temperature from this distinctive frequency.

The world’s tiniest temperature sensor is powered by radio waves – [Link]

Fobble – A general purpose Wireless Breakout Board!

Fobble_4

Ken Boak has designed a compact board with RFduino Bluetooth Low Energy Module:

This week I have been working on another of my standard footprint 50mm x 50mm boards – it is a general purpose wireless module carrier board:- Fobble. That’s a BLE Fob – for anyone who misses the pun.

In the last few weeks there have been a number of applications arise – that could easily be addressed with an easy to use, generic wireless platform. These have included keyfob or pendant applications – requiring a small coin cell powered board – to a generic wireless board that can be stacked to one of the processor boards to provide wireless connectivity.

Fobble – A general purpose Wireless Breakout Board! – [Link]

High Reliability, High Isolation Single-Pole-Double-Throw RF switch

In telecommunications, ideal RF switches require low insertion loss, high isolation and linearity. The IDT F2912 is a single-pole-double throw RF switch capable of having low insertion of loss of 0.4dB at 1GHz and a RF1 to RF2 Isolation of 74dB at 1GHz with extended temperature of -55C to +125C making it highly reliable. In addition, this covers a broad frequency range from 300kHz to 8000MHz.

As a switch, it’s capable of 3 types of controls namely switch control, mode control, and logic control. The switch control includes (3 states and 2-pin control input) or (2 states and 1-pin control input). The 3 states and 2-pin control input operates like a XOR logic gate, if there is a high value input from the control pin either CTL1/CTL2 will trigger RF1 to RF Com if CTL1 is High or RF2 to RF Com if CTL2 is High. While the 2 states and 1-pin control input, a high value CTL2 will trigger RF2 to RF com and a low value CTL2 triggers RF1 to RF Com leaving the CTL1 a “don’t care”. The mode control use either (2-pi

n control: CTL1 and CTL2) or (1-pin control: CTL2). When RF1 and RF2 ports are both open (State 1), all 3 RF ports are terminated to an internal 50Ω termination resistor. When RF1 or RF2 port is open (State 2 or State 3 OFF condition), the open port is connected to an internal 50Ω termination resistor. When RF1 or RF2 port is closed (State 2 or State 3 ON condition), the closed port is connected to the RF Com port. The logic control operates using logic voltage 1.8V and 3.3V to operate logic CTL (pin18) VCC and GND respectively.

This circuit design can be applied more on base station 2G, 3G, 4G, portable wireless, repeaters and E911 systems, digital pre-distortion point to point infrastructure, public safety infrastructure WIMAX receivers and transmitters, military systems, JTRS radios, RFID handheld and portable readers, cable Infrastructure, wireless LAN, test/ ATE Equipment.

High Reliability, High Isolation Single-Pole-Double-Throw RF switch – [Link]

Wireless Transmitter System

This wireless project is a power transmission system, it works on the principle of magnetic induction. This Wireless Charging system works as the digital switched mode power supply with the transformer, which is separated into two parts: The transformer primary coil is on the transmitter, working as the transmitter coil, and the transformer secondary coil is on the receiver side as the receiver coil. This system works based on magnetic induction, the better coupling between the transmitter coil and receiver coil gain, the better system efficiency. So the receiver coil should be closely and center aligned with the transmitter coil as possible. After the receiver coil receives the power from the transmitter coil by magnetic field, it regulates the received voltage to power the load, and send its operational information to transmitter according to specific protocol by the communication link. Then the system can achieve the closed-loop control, and power the load stably and wirelessly. Continue reading Wireless Transmitter System

Simple, easy and cheap wireless presenter

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by Dimitris Platis @ instructables.com:

During presentations, I avoid being stationary and generally like to walk around in order to increase the interaction between me and the audience. However, I am constantly being faced with the burden of having to go back to the laptop, in order to change a slide or tell a person sitting by the laptop to do that. Not cool!

This problem is usually solved by devices, called remote clickers or wireless presenters, which consist of a handheld controller with buttons that sends signals to a USB dongle plugged in the computer. After looking around to buy one, I could not find any decent option costing less than 10$. So why not make one?

Simple, easy and cheap wireless presenter – [Link]

Mini weather station

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by indigod0g @ instructables.com:

In this project, we will be making a mini weather station that measures temperature and humidity and transmits them wirelessly to a ground station, which displays the readings on an LCD display!

It’s a fairly easy project and can be used either on its own or part of something bigger.

Mini weather station – [Link]

Wireless Power Outlets RF from Raspberry Pi

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by Tim @ timleland.com:

Have you ever wanted to wirelessly control power outlets from your phone? You could buy a Belkin WeMo Switch for over $40 for 1 outlet or build your own with 5 outlets for under $35 if you already own a Raspberry Pi. Hopefully this post will guide you in the right direction.

Wireless Power Outlets RF from Raspberry Pi – [Link]

Wireless IR Headphone Transmitter

HEF4046BT

Infrared headphones can be used for listening to music or television cordlessly. The headphones utilize a transmitter that connects with audio cables to the audio source, such as a home entertainment center. The transmitter utilizes light-emitting diodes (LEDs) to direct a focused beam of invisible pulsating light towards a receiver built into the headphone set. The pulsations act as ON/OFF signals that are translated digitally by the receiver into audible sound waves. Most infrared headphones have an effective range of about 30 feet (~10 meters) or less, and require a clear line of sight between transmitter and receiver.

Sound comes out of the stereo system through audio cables and into an infrared transmitter. The transmitter turns the sound into a series of pulses. The pulses work like bits in a computer, digitally capturing the sound information. These pulses are then sent to an infrared LED.

For the transmitter side, an audio input from PL1 frequency modulates the VCO section of a HEF4046BT PLL chip. The VCO output drives Q1, a switching transistor. Q1 drives two IR LEDs. The signal produced is around 100 kHz, FM carrier VCO sensitivity is around 7.5 kHz/V.

Wireless IR Headphone Transmitter – [Link]