Using Efficient SPI Peripherals for Low-Cost MCU-Based IoT Designs


by Warren Miller @

Efficient Internet of Things (IoT) designs must balance a host of requirements that often work against each other. Low cost is important, but often supporting all the key features required by the application increases MCU pin count and memory size—two things that work against low cost. Low power is also important for IoT applications where battery operation is a must. Adding features and improving performance can up the power requirement, however. Clearly finding the right balance between all these requirements can be a problem, but that’s just the type of challenge engineers expect from cutting-edge designs.

Using Efficient SPI Peripherals for Low-Cost MCU-Based IoT Designs – [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. (more…)

Arduino Watch With Altitude, Temperature, Compass And Pedometer


by benhur.goncalves @

Hi folks! Last few days I’ve been obsessed with the idea to make my own watch from arduino parts, but something cool I could use and say I did it myself. So I found out there was a sensor board (commonly named GY-87) which had three sensors on it: HMC5883L (compass), BMP085 (pressure, altitude, temperature) and MPU6050 (accelerometer and gyroscope). With it, via I2C, I could add an Arduino Pro Mini, and an I2C Oled Display and make a watch capable of having all this information, plus a pedometer (by analysing accelerometer data).

Arduino Watch With Altitude, Temperature, Compass And Pedometer – [Link]

Externally clocking (and overclocking) AVR MCUs



People familiar with AVR boards such as Arduinos likely know most AVR MCUs can be clocked from an external crystal connected to 2 of the pins. When the AVR does not need to run at a precise clock frequency, it is also common to clock them from the internal 8Mhz oscillator. Before CPUs were made with internal oscillators or inverting amplifiers for external crystals, they were clocked by an external circuit. Although you won’t see many AVR projects doing this, every AVR I have used supports an external clock option.

Externally clocking (and overclocking) AVR MCUs – [Link]

ESP8266 Weather Station with Arduino


by ohneschuh @

I read about the ESP8266 first in March this year and I didn’t know what to do with. And now I’m really fascinated how easy the connection of an Arduino to the Internet can be. Like others I set up a weather station on a breadboard first and sent data to This ends up in a highly condensed stripboard layout and the needed software package.

What are the functionalities?
measure temperature, humidity, pressure and illuminance (brightness)!
send all data to thingspeak
ESP8266 can be turned on and off by Arduino for energy saving
additional digital IOs
Runs on 5 to 12 V
and a lot more

ESP8266 Weather Station with Arduino – [Link]



ATmega16/32 Development Board provides a very simple and cost effective platform for prototyping solution.  The compact design provides connection to all the pins of the microcontroller for the user.

  • Prototyping solution available for 40-pin ATmega series AVR microcontroller from ATMEL
  • All the four ports available to the user via standard 10 pin box header connector with supply of 5 VDC for interfacing circuits
  • Onboard reset switch for easy reset of the microcontroller


Narrowband RF Power Amplifier (520MHz)

The RF power amplifier stage is usually the final active block of any electronic system that is transmitting RF power. Relatively low power RF signals are amplified to produce a more powerful signal in order to be transmitted over greater distance. RF output power can range from a few mW to MW, depend by application. RF amplifiers before were all made using vacuum tubes but modern RF amplifier nowadays uses solid state devices like MOSFET, TMOS-FET, Bipolar junction transistors, and IGBT to amplify RF signals.

This circuit features the Freescale AFT05MP075GNR1 RF power LDMOS transistor as its RF amplifier solid state device. With the use of some components and proper board layouting, Freescale was able to create a 70 watts RF power amplifier with a gain of 18.5dB. This circuit requires a 12.5Vdc power supply able to provide the maximum power this LDMOS transistor can give. In this circuit, AFT05MP075GNR1 was configured to amplify RF signal with a carrier frequency of 520MHz suitable for UHF band mobile radio applications.

The Freescale AFT05MP075GNR1 was designed for mobile two-way radio applications with frequencies ranging from 136 to 520 MHz. It can be configured as a narrowband or wideband RF power amplifier. The high gain, ruggedness and broadband performance of this device make it ideal for large-signal, common source amplifier applications in mobile radio equipment. It can operate exceptionally in a very wide temperature range, from -40 to +150 degree Celsius. Though this device handles wideband application, it can still give full power across the band.

Narrowband RF Power Amplifier (520MHz) – [Link]

LDO regulator is qualified for automotive designs

Micrel MAQ53

by Susan Nordyk @

Housed in a tiny 2×2-mm, 6-pin DFN package, the MAQ5300 voltage regulator from Micrel boasts a dropout of only 100 mV at 300 mA. The AEC-Q100-qualified part is suitable for space-constrained and high-reliability applications that are subjected to the harsh environments and temperatures commonly encountered in automotive and industrial applications.

The CMOS regulator operates from an input voltage of 2.3 V to 5.5 V, while delivering a guaranteed output current of 300 mA. Fixed output-voltage options include 1.5 V, 1.8 V, 2.5 V, 2.8 V, 2.85 V, 3.0 V, and 3.3 V. Output voltage noise is specified at 120 µV RMS typical. The MAQ5300 also achieves an initial output voltage accuracy of ±2% and ±3% over temperature.

LDO regulator is qualified for automotive designs – [Link]