LTC4125 – 5W AutoResonant Wireless Power Transmitter


The LTC4125 is a simple and high performance monolithic full bridge resonant driver capable of delivering over 5W of power wirelessly to a properly tuned receiver. The device controls the current flow in a series connected transmit coil LC network to create a simple, safe and versatile wireless power transmitter.

The LTC4125 wireless power transmitter improves upon a basic transmitter by providing three key features: an AutoResonant function that maximizes available receiver power, an Optimum Power Search algorithm that maximizes overall wireless power system efficiency, and Foreign Object Detection (FOD) to ensure safe and reliable operation when working in the presence of conductive foreign objects.

LTC4125 – 5W AutoResonant Wireless Power Transmitter – [Link]

Open-source OBD adapter


Alex @ has published a new open source OBD adapter which provides you a serial interface using the ELM327 command set and supports all OBD-II standards.

The adapter kit schematic is shown here. It is built around NXP LPC1517 Cortex-M3 microprocessor with 64 kB program memory, but can accommodate another chip from same family like LPC1549 with 256 kB if required. The NXP chips has a ROM-based bootloader that supports loading a binary image into its flash memory using USART or CAN. All the software is written in C++ for NXP LPCXpresso IDE which is essentially using GNU toolchain for ARM Cortex-M processors. However, it can be compiled with other pre-built GNU toolchain, like GCC ARM Embedded or even with Keil uVision IDE.

Open-source OBD adapter – [Link]

How to measure mass of the Earth using Arduino


victoryking @ has posted a nice physics and arduino tutorial on how to measure the mass of earth. This is an indirect method to calculate the mass of earth by measuring acceleration due to gravity with the help of arduino.

One fine day, I was weighing my self on a weighing scale. Suddenly a thought came to my mind, ‘How much would be the mass of Earth?’. Leave that apart ‘How can we even measure it?’. There is no such weighing scale on which, Earth can be placed. There has to be some indirect way to measure mass of the Earth. Here I present implementation of one such indirect method to measure mass of the Earth.

How to measure mass of the Earth using Arduino – [Link]

FeatherHAB (Balloon Tracker) Firmware & Hardware Source Released


Ethan Zonca has released the firmware and hardware of FeatherHAB. FeatherHAB is a small and inexpensive ballon GPS tracker.

FeatherHAB is a lightweight, small, and inexpensive balloon tracker. It tracks the location of a balloon with GPS and broadcasts the balloon’s position to the APRS network on 144.390MHz. The tracker is built around a Ublox MAX8 GPS module and a custom RF transmitter designed with the Silicon Labs Si446x transceiver IC. Power is supplied by a single-cell Lithium battery, which runs through a tiny buck-boost converter to power the system. The total weight comes in at about 2 grams without a battery.

FeatherHAB (Balloon Tracker) Firmware & Hardware Source Released – [Link]


ATmega8 Thermocouple Thermostat

driver_board_front_2 has published a thermocouple thermostat based on ATmega8 and  MAX31855KASA Thermocouple to digital converter IC from Maxim.

Here is a circuit, I used popular thermocouple type K and MAX31855KASA+ to interface it. I could also put some op amp, and connect to Atmega8’s ADC, but 31855 is for lazy people and has everything inside, just connect thermocouple, and get data through SPI interface. It has also some nice features, like error detect (if therm. is damaged or shorted to VCC or GND), it’s not so cheap from the other side.

ATmega8 Thermocouple Thermostat – [Link]


Multi-Function SSD Shield for the Raspberry Pi 2


We came across this kickstarter campaign that features a multifunction SSD shield for Raspberry Pi 2. The shield includes SSD, WiFi, RTC w/Battery and high power USB:

Pi 2 Design is excited to introduce the first offering in a new line of Embedded and Media-based I/O shields for the popular Raspberry Pi 2. The CSB502SSD Multi-Function Solid State Drive shield allows users to create a low cost, high performance, embedded network storage device. The powerful combination of the CSB502SSD and the Raspberry Pi 2 lets you leverage the ever expanding RPi 2 ecosystem for a wide variety of Embedded, Data Storage, Medical and Industrial applications.

Multi-Function SSD Shield for the Raspberry Pi 2  – [Link]


Arduino – Processing Laser CNC Project

Neumi @ has build an Arduino based CNC project and source files are provided.

This is my scratch build Laser CNC Engraver and PCB Exposer. It uses a 150mW 405nm laser diode and two CD drive motors and mechanics. A Processing sketch calculates the position of the pixels and send them to an Arduino Mega, wich drives the steppermotors. A TTL driver is used to control the Laser. With the joystick you can control the laser. You can set the exposure time, so you can engrave foam, paper, leather, plastic and wood. If you engrave photo-coated PCBs its possible to harden the surface and create your custom made PCBs.
The resolution is at about 100 pixels/cm. The work area is 3,2 x 3,2 cm.

Arduino – Processing Laser CNC Project – [Link]

Circuit lets you test capacitors for leakage


Raju R Baddi @ has published a circuit that enable you to test electrolytic capacitors and decide if worth using it on a circuit.

The values in the figure are typical for general testing of all capacitors, from 1-nF ceramic versions to 1000-μF electrolytic types. The value of CREF in the circuit is near the value of the test capacitor, CX. You can also choose RREF, by a rotary-switching arrangement, to be greater than or less than 22 MΩ.

Circuit lets you test capacitors for leakage – [Link]

RFM69 to MQTT gateway using ESP8266


Martin @ has published an article on how to forward traffic from RFM69 to MQTT using  ESP8266:

I’ve mentioned my plans for this project during the IoT hangout session few months ago, it has finally materialized as working prototype. The blocker so far was the lack of ESP8266 RFM69 driver and free time on my end, so I’ve teamed up with Andrey Balarev to solve this. Andrey is an IoT enthusiast + embedded systems developer and has done excellent job in porting LowPowerLab’s RFM69 library for the ESP8266.

RFM69 to MQTT gateway using ESP8266 – [Link]