Pixie – 3W chainable smart LED Pixel


Ytai Ben-Tsvi @ ytai-mer.blogspot.com build a PIC based 3W LED Driver that is chainable. He writes:

LED Pixel: The Pixie is a color LED module, allowing an external controller to change its color and brightness dynamically.
Chainable: The module is designed so that you can chain many of them and control each one individually. If you know NeoPixels, this concept should be clear, but in case you don’t, imagine you want to build a project that requires 50 LEDs to be individually controlled. Naively, you would need to power each on of them individually, then connect each one of them individually to a controller. This would require tons of wiring, many pins on the controller, each one possibly driven by a specialized peripheral, such as UART or PWM. In short, this is not practical. With the Pixie, being chainable, you connect the first LED’s input pins to power and a single control pin (serial TX) on the controller. Then you connect the first LED’s output pins (power, ground, data) to the input of the second LED, and so on. Each Pixie in the chain consumes its own data, then relays the rest of the data down the chain, so the controller can control each Pixie individually, without being connected to each one.

Pixie – 3W chainable smart LED Pixel – [Link]

DC Servo Motor Driver – Analog Closed Loop Control


Versatile project has been designed to use in automotive application and industrial servo control application. This project provides all active necessary functions for closed loop servo system using Brushed DC Motor and potentiometer mounted on output shaft of DC Motor Gear. This project is ideally suited for almost any servo positioning application.


  • P2: Position Potentiometer
  • P1: Fed Back potentiometer couple with DC Gear Motor output shaft
  • CN1: Power Input 12V-30V DC
  • Motor: DC Motor

DC Servo Motor Driver – Analog Closed Loop Control – [Link]

DRV8871 – 3.6A Brushed DC Motor Driver


The DRV8871 is a brushed-DC motor driver for printers, appliances, industrial equipment, and other small machines. Two logic inputs control the H-bridge driver, which consists of four N-channel MOSFETs that can control motors bidirectionally with up to 3.6-A peak current. The inputs can be pulse-width modulated (PWM) to control motor speed, using a choice of current-decay modes. Setting both inputs low enters a low-power sleep mode.

DRV8871 – 3.6A Brushed DC Motor Driver – [Link]

iCoupler – Digital Signal Isolator


Clemens Valens @ elektormagazine.com discuss about the new iCoupler family of isolators from Analog Devices:

Digital isolators based on transformers and capacitors use magnetic and electric fields to couple data across isolation barriers where optocouplers use light. Digital isolators can be manufactured using CMOS technology allowing the integration of signal conditioning circuitry in the chip to greatly reduce power consumption and improve data transfer rates.

The iCoupler family from Analog Devices is a family of digital isolators that feature up to 16 kVpk surge protection and that can withstand voltages up to 5 kV. Signal speeds go up to 150 Mbit/s.

iCoupler – Digital Signal Isolator – [Link]


Disco Lights with IC555


This is a simple 555 timer IC circuit that is able to power two strings of LEDs alternative.

Disco lights are mostly used in decoration made with colourful LEDs. For begginners, this is a compact circuit using a single chip IC. IC555 is connected here to form a multivibrator. The blinking speed can be easily adjusted by varying the preset 500kΩ. You can use any colour of LED.

Disco Lights with IC555 – [Link]

Choosing $1 sound card for DC-capable low speed oscilloscope


Tomasz Ostrowski has tested some cheap USB sound cards as low speed oscilloscope interfaces/recorders. He writes:

I’ve tested some cheap ($1) USB sound cards for DC sampling capability, in particular for using as low speed oscilloscope/signal recorder. Some (http://tomeko.net/dsoundscope/c_media.php or one from this thread: http://www.elektroda.pl/rtvforum/topic3106124.html) don’t seem to work despite removing DC blocking capacitor, but this one: http://tomeko.net/dsoundscope/C_Media2/ is fine. With just 120k resistor connected it is able to measure voltage from 0-6V range (cons: its input is at 2V level, sourcing 8uA if connected to GND and it’s single channel only). For test purposes I’ve prepared DLL interface for miniscope v4 (Win32 oscilloscope GUI) calibrated for this particular setup (example traces available).

Choosing $1 sound card for DC-capable low speed oscilloscope – [Link]

CCS811 – Digital CMOS gas sensors for wearables & IoT


by Graham Prophet @ edn-europe.com:

Cambridge CMOS Sensors is a semiconductor company that designs gas sensor solutions to monitor the local environment; its CCS811 is the first digital product in its CCS800 product family of ultra-low power miniature gas sensors.

The CCS811 integrates a metal oxide gas sensor with a microcontroller sub-system which enables Indoor Air Quality Monitoring, ease of design, extended battery life and reduced system cost for smartphones, wearables and connected home devices. It is based on CCS’s Micro-hotplate technology which enables a highly reliable solution for gas sensors, very fast cycle times and a significant reduction in average power consumption compared with traditional metal oxide gas sensors.

CCS811 – Digital CMOS gas sensors for wearables & IoT – [Link]

Using The Arduino Serial Plotter

idogendel.com introduces us the new serial plotter feature of Aruino IDE 1.6.6:

A little unofficial introduction to the Serial Plotter, introduced in the Arduino IDE version 1.6.6. This is a very basic and easy-to-use tool, that allows us to set up quick visualizations of numeric data for whatever purpose.

Using The Arduino Serial Plotter – [Link]

Ovenized crystal oscillator frequency stability


E. Schrama @ ejo60.wordpress.com uses an Arduino and a DCF77 time signal receiver to test the stability of an ovenized crystal oscillator running at 1 MHz.

In this experiment I will use an Arduino and a DCF77 time signal radio receiver to measure the stability of an ovenized crystal oscillator running at 1 MHz. It demonstrates that 50ppb (or 50 milliHerz) can be achieved on the short term, whereby an aging effect of 0.1 ppb per day is demonstrated with a 18 month long dataset. The output of the 1MHz oscillator is fed into a 248 counter and six 74HC165 parallel in, serial out (piso) conversion ICs that are controlled by an ATMEGA 2560, the circuit is described here. With this setup running at 1 MHz you get a rollover every 10 years, the resolution is 1 microsecond. In principle you could do this also with an Arduino but I decided for this set-up since I already had most of the components left over from an earlier experiment.

Ovenized crystal oscillator frequency stability – [Link]

Non-Contact Body Temperature Meter

One of the most commonly used medical instruments nowadays is the thermometer. The thermometer is used to monitor or measure the body temperature of a sick person. The idea of creating a thermometer started from a device called thermoscope, a thermometer without a scale. Several inventors developed it until Sir Thomas Allbutt invented the first practical 6-inch medical thermometer able to sense a body temperature in five minutes. The development of the thermometer did not stop there and today, digital thermometer exists which is faster and very accurate.

This reference design is an example of a low cost non-contact digital thermometer. It only uses a microcontroller, a four digit seven segment display and an infrared (IR) temperature sensor. The concept of this design is to make the IR sensor measure the temperature of the thermal radiation emitted by the body being measured. The data acquired by the sensor will be sent to the microcontroller through the I2C bus. The microcontroller will analyze the data and then shows the body temperature on the four-digit seven-segment display.

The circuit of this reference design uses few components only and is very easy to understand. However, to make the circuit function accurately, software calibration must be implemented carefully. The whole circuit is powered by a 5V DC power supply regulated from the four 20mm coin shape batteries contained in a 120591-1 TE Connectivity battery holder. The batteries are connected in series-parallel connection to produce a 6V 480mAh source of power. With the help of a low-dropout voltage regulator, the 6V is regulated to a 5V DC supply

Non-Contact Body Temperature Meter – [Link]