Horst Gether @ edn.com writes about how the simple and well established 3.5mm jack can be used for data-rich communication between headset and mobile device.
The 3.5mm phone jack is a well-established standard in the audio industry and continues to get strong support from users in the market. Originally invented in the 19th century for telephone switch boards, it made its way into mobile phones, tablets, and personal computers to connect audio and communication headsets for phone calls or simply for listening to music. While the phone jack has a rather long evolutionary history, the functionality that the 3.5mm four-pole accessory device provides to its end customers is rather limited.
Data-rich 3.5mm jack vies with USB-C for headsets – [Link]
6V Lead acid (SLA) battery charger project is based on BQ24450 IC from Texas instruments. This charger project takes all the guesswork out of charging and maintaining your battery, no matter what season it is. Whether you have a Bike, Robot, RC Car, Truck, Boat, RV, Emergency Light, or any other vehicle with a 6v battery, simply hook this charger maintainer up to the battery. The bq24450 contains all the necessary circuitry to optimally control the charging of lead-acid batteries. The IC controls the charging current as well as the charging voltage to safely and efficiently charge the battery, maximizing battery capacity and life. The IC is configured as a simple constant-voltage float charge controller. The built-in precision voltage reference is especially temperature-compensated to track the characteristics of lead-acid cells, and maintains optimum charging voltage over an extended temperature range without using any external components. The low current consumption of the IC allows for accurate temperature monitoring by minimizing self-heating effects. In addition to the voltage- and current-regulating amplifiers, the IC features comparators that monitor the charging voltage and current. These comparators feed into an internal state machine that sequences the charge cycle.
6V Lead Acid Battery Charger using BQ24450 – [Link]
6V Lead acid (SLA) battery charger project is based on BQ24450 IC from Texas instruments. This charger takes all the guesswork out of charging and maintaining your battery, no matter what season it is. Whether you have a Bike, Robot, RC Car, Truck, Boat, RV, Emergency Light, or any other vehicle with a 6v battery, simply hook this charger maintainer up to the battery. The BQ24450 contains all the necessary circuitry to optimally control the charging of lead-acid batteries. The IC controls the charging current as well as the charging voltage to safely and efficiently charge the battery, maximizing battery capacity and life. The IC is configured as a simple constant-voltage float charge controller. The built-in precision voltage reference is especially temperature-compensated to track the characteristics of lead-acid cells, and maintains optimum charging voltage over an extended temperature range without using any external components. The low current consumption of the IC allows for accurate temperature monitoring by minimizing self-heating effects. In addition to the voltage- and current-regulating amplifiers, the IC features comparators that monitor the charging voltage and current. These comparators feed into an internal state machine that sequences the charge cycle.
For low charging current, you can use SMD Q1 transistor on the bottom of PCB, for higher charging currents you should use a through-hole (TO247) transistor, like TIP147 on the top of PCB.
The circuit has been designed for PNP transistor (Q1) that’s why the PCB jumper is shorted to R8 by default. You can also use an NPN transistor, in this case, Omit R6, Use R2, Jumper has to be shorted the other way.
Thanks to a partnership with Nordic Semiconductor – the world’s most successful open-source ecosystem for education, Maker, and Internet of Things (IoT) markets -, Arduino announced its new board, Arduino Primo, including native Bluetooth Low Energy wireless connectivity and NFC touch-to-pair using Nordic nRF52832 SoCs.
The Arduino Primo combines the processing power from the Nordic nRF52 processor, an Espressif ESP8266 for WiFi, as well as several on-board sensors and a battery charger. The nRF52 includes NFC (Near Field Communication) and Bluetooth Smart. The sensors include an on-board button, LED and infrared receiver and transmitter.
There are three onboard microcontrollers:
nRF52832, the main Arduino microcontroller with integrated BLE and NFC
STM32f103, a service microcontroller used for advanced debugging and programming of the other microcontrollers
ESP8266, for Wi-Fi and related internet connectivity functions.
The board has:
14 digital input/output pins (of which 12 can be used as PWM outputs)
6 analog inputs
64 MHz ceramic resonator
micro-USB connector
ICSP header
battery charger
Infrared receiver and transmitter
NFC antenna
BLE interface
Buzzer
two service buttons
LEDs
reset buttons (to reset the various microcontrollers).
Arduino Primo can be connected to a computer using a micro-USB cable, or it can be powered using a battery, connected via a 2-pin JST-PH connector. Having both Bluetooth and Wi-Fi connectivity on board makes it easy to get started in the IoT world.
“Our passion at Arduino is to provide the tools to encourage passionate people to build out their ideas and bring them into the world. Adding wireless connectivity from our partnership with Nordic provides even more options,” says Federico Musto, CEO & President of Arduino S.r.L. “Ease-of-use is one of our core strengths, and this makes the Nordic chip a perfect match for the Arduino Primo,” adds Musto.
More details about Arduino are available at the official page at Arduino.org
While building an ultra-low power application, sensitive hardware and software validation is required to reach system and long battery life. Testing will need an interaction with the tested parts, like simulating input pins of the target application.
These difficulties could be solved with ARM’s new debug adapter “ULINKplus“. It connects the target system with the PC through USB port using a 10-pin Cortex Debug connector. Its power measurement technology allows developers to program, debug, and analyze their applications and their power consumption.
Main features of ULINKplus are:
Integrated power measurement synchronized to event tracing which makes it easy to optimize the overall energy envelope of a system.
Isolated JTAG/serial-wire connection to the target hardware is essential for testing applications such as motor control, power converters, or systems with sensitive analog processing.
Additional test I/O pins are accessible from the debugger and debug scripts to interact with the target and control automated test stands.
ULINKplus, together with MDK, provides extended on-the-fly debug capabilities for Cortex-M devices. You can control the processor, set breakpoints, and read/write memory contents, all while the processor is running at full speed. High-Speed data trace enables you to analyze detailed program behavior.
In addition to downloading programs to your target hardware, you will be able to examine memory and registers, single-step through programs and insert multiple breakpoints, to run programs in real-time, program Flash memory, and to connect to running targets (hot-plugging).
Live data from power measurement
ULINKplus offers a high speed connections that reach 50 Mbit/s for data and event trace for Cortex-M, 20 MHz JTAG clock speed, and 3 MBytes/s high-speed memory read/write.
SeeedStudio has published a PCB design manual to help makers and engineers design better PCBs. The guide covers many aspects of PCB design for manufacture summarizing the experience of their PCB service over the last 9 years.
Apple said goodby to 3.5mm audio jack in Iphone 7 by adding the audio signal to USB plug besides the other functionalities. While Iphone is a pioneer brand, a lot of manufacturers in the near future will drop that analog jack. However, your ear responds to analog signals only. So either you buy headphones with built-in USB audio to analog converter, or you use your old headphones with an adapter. This “new” demand for converting between USB and analog increases the need for ready made solutions.
IPhone 6 and iPhone 7 ports comparison — By Rafael Fernandez (Own work) CC BY-SA 4.0 , via Wikimedia Commons
Silicon Labs has a lot of solutions for USB fixed-function chips. A new IC from Silicon Labs called CP2615 serves as a digital audio bridge transferring digital audio data between the USB and integrated I2S serial bus interfaces with no firmware development needed. CP2615 is available in 5mm x 5mm QFN-32 package and includes a USB 2.0 full-speed function controller, USB transceiver, on-chip oscillator, I2S audio interface, integrated I2C to communicate with DACs/codecs and embedded flash memory for storing device configurations.
CP2615 has a number of properties that need to be configured like Audio Sample Rates, selecting audio interfaces and others. They can all be configured using “Xpress Configurator” available in Silicon Lab’s IDE (Simplicity Studio).
Around one and a half years ago I’ve designed and built various LED dimmers for both white and RGB LEDs. Then late last year someone approached me asking if I could make an RGB dimmer for him, too. But my designs were really tailored to their specific applications and built with home-made, i.e. milled PCBs which are time-consuming to make. So I decided to make a more universal version based on a proper, etched board which could be built in a small series and used for all kind of applications, both white and RGB. The result is this versatile, programmable 4-channel dimmer.
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