Thursday, December 31, 2015

Building an AC Power Switch Development Board

Ever want to create a design that automates turning on or off an AC powered device such as a light or a heating system? Well this video is for you! In this video we look at how to create a development board for switching on and off AC power. The switch is implemented with a TRIAC which is a semiconductor device so no moving parts like a relay based design. You can access the Eagle PCB layout files from this link or you can purchase this development board from

Download Eagles files from GitHub:

*********************************Arduino code shown in the video********
//This sketch is used to control Thyristor that is used as a switch to turn on and off an AC line powered light. //This code is free for all to use
int8_t dig = 0; //default is high for light off

void setup() {
  //for controlling Thyristor
  pinMode(7, OUTPUT); //set pin to output so it can sink current from optoisolator
  digitalWrite(7, HIGH); //when high the thyristor is off or open

void loop() {
  delay(3000); //light turns on / off every 2 seconds
  togLight(); //call function to turn light on / off using digital pin

void togLight() {
  if(dig) { 
     digitalWrite(7, HIGH); //turn off light
     dig = 0; //toggle dig value
  else {  
     digitalWrite(7, LOW); //turn light on
     dig = 1; 

Tuesday, December 22, 2015

Building a Wireless Sensor Network with the nRF24L01 Part 2

In part 2 we focus on powering our wireless sensor node. We talk about batteries, battery sizing, estimating battery life, and battery monitoring. If you have any feedback or questions use the comments section below.

Updated Schematic for Part 2

Monday, December 7, 2015

Building a Wireless Sensor Network with the nRF24L01 Part 1

This is part 1 in a series where we look at how to build a large wireless network using Arduino and the nRF24L01+ Transceiver Modules. At the end of this series you will have a reference design for a wireless sensor development board and the code needed to turn the wireless sensor developments boards into a network. You will be able purchase all the hardware for this project at my site:

Initial Hardware Design