Alexa for Home Automation

Reflection

Reflection

At BlueStamp, I learned a lot from hands-on projects and documentation. Even with the highly trained faculty leading me through problems and issues in my modifications and milestones, there was a lot of room for me to decide the next step and fix my own issues. I learned subjects from Arduino programming to circuitry and using components on my breadboards. Learning to apply my own struggles to the world of engineering meant that my milestones came out more meaningful and exciting. I enjoyed connecting with my peers and listening to what they had to offer in terms of helping me advance my engineering career.

Main Project: Final Modification

Main Project: Modification One

After Milestone 2, I had to think about additional features that I could add to Alexa’s skills. I thought about a wireless keyboard, an automated coffee maker, blinds, and a tv remote. For this particular milestone, I decided to create a TV remote. By using an IR light and receiver, I was able to read the different frequencies of each button on the original remote and then map them into my Particle code. The IR light then transmits a constant frequency of 38kz in certain time intervals listed in an array. Different arrays of time values are used to mimic different buttons on a TV remote(as shown in the first GitHub Gist), meaning that each button needs its own array.

IR Arrays

	unsigned int dataon[67] = {8800,4450, 550,1600, 550,1650, 550,1650, 550,550, 550,550, 550,550, 550,550, 550,1600, 550,1650, 550,600, 500,1650, 550,550, 550,550, 550,550, 550,1650, 500,600, 500,1650, 550,1650, 550,1650, 550,550, 500,1700, 500,550, 550,550, 550,550, 550,550, 550,550, 550,550, 550,1600, 550,600, 500,1650, 550,1600, 600,1650, 550}; // NEC E1A2E817
	unsigned int dataComp[67] = {8850,4350, 600,1600, 600,1600, 600,1600, 550,550, 550,550, 550,500, 600,500, 600,1600, 600,1600, 550,550, 550,1650, 550,500, 600,500, 550,550, 550,1650, 550,550, 550,550, 550,550, 550,550, 550,1600, 550,1650, 550,550, 550,550, 550,550, 550,1650, 550,1600, 600,1600, 550,550, 550,550, 550,1650, 550,1600, 600,1600, 550}; // NEC E1A218E7
	unsigned int dataVideo[67] = {8800,4400, 550,1650, 550,1650, 550,1600, 550,550, 550,550, 550,550, 550,550, 550,1650, 550,1650, 550,500, 550,1650, 550,550, 550,550, 550,550, 550,1650, 550,550, 550,1650, 500,550, 550,550, 550,1650, 500,1700, 550,550, 500,550, 550,550, 550,550, 550,1650, 550,1650, 500,600, 550,550, 550,1650, 500,1650, 550,1650, 500}; // NEC E1A29867
	unsigned int dataSearch[67] = {8850,4350, 550,1650, 550,1650, 550,1650, 550,550, 550,500, 600,500, 550,550, 550,1650, 550,1650, 550,550, 550,1600, 600,500, 550,550, 550,550, 550,1650, 550,550, 550,550, 550,1600, 600,500, 550,1650, 550,1650, 550,550, 550,550, 550,550, 550,1600, 600,500, 550,1650, 550,550, 550,550, 550,1650, 550,1600, 600,1600, 550}; // NEC E1A258A7

view raw Arrays.ino hosted with ❤ by GitHub

Circuiting/Wiring

Modified Photon Code to Transmit IR

Code

	IRTransmitter transmitter(IR_PIN, LED_PIN);
	int controlled(String args){
	// Turn on/off LEDs
	int pos = args.indexOf(',');
	bool tv = false;
	if(-1 == pos){
	return -1;
	}
	String strPin = args.substring(0, pos);
	String strValue = args.substring(pos + 1);
	Serial.println();
	Serial.print("Pin: ");
	Serial.print(strPin);
	Serial.print(" ");
	Serial.print("Value: ");
	Serial.print(strValue);
	Serial.println();
	int pin = D0;
	int value = HIGH;
	if(strPin.equalsIgnoreCase("D0")){
	pin = D0;
	}
	else if(strPin.equalsIgnoreCase("D1")){
	pin = D1;
	}
	//TV remote
	else if(strPin.equalsIgnoreCase("D2")){
	//TV on or off, sends power button signal
	if(strValue.equalsIgnoreCase("HIGH")){
	tv = true;
	transmitter.Transmit(dataon, sizeof(dataon) / sizeof(dataon[0]));
	}
	//TV switch inputs command
	else if(strValue.equalsIgnoreCase("SEARCH")){
	tv = true;
	transmitter.Transmit(dataSearch, sizeof(dataSearch) / sizeof(dataSearch[0]));
	}
	}
	else{
	return -2;
	}
	if(strValue.equalsIgnoreCase("HIGH")){
	value = HIGH;
	}
	else if(strValue.equalsIgnoreCase("LOW")){
	value = LOW;
	}
	else{
	return -3;
	}
	if(tv == false){
	digitalWrite(pin, value);
	}
	if(tv == true){
	return 1;
	}
	// return 1;
	}

view raw Alexa.ino hosted with ❤ by GitHub

There were a lot of issues that had to be resolved when finishing this milestone. The first was the limitation of Particle libraries and the lack of working functions that I could use to transmit the IR codes in the first place. I tried to use only the encoded NEC code with a function sendNEC() which takes in one hex code and a bitrate to transmit an entire signal. However, I never got this function to work. I instead turned to sending raw array inputs which proved to take a longer time to send but eventually got my signal across. The only problem with the timing is the projector. For the projectors that I had to test my remote on, the turn off sequence required two taps of the off button. This meant that I needed to send two signals almost back to back(in the span of 1.5-2 seconds since the “Are you sure you want to turn off?” screen stayed there for that long). For my particle, sending one signal took a long time to cool down and therefore required at least 3-4 seconds between transmissions. I solved this through Amazon’s Web Services to make Alexa send two back to back signals which somehow fixed the issue. By sending multiple commands through, I tricked the Particle to start the transmission again one second after the first one went through. Overall, this milestone took a while to achieve, from brainstorming to getting parts to eventually running into IR light issues. After this, I plan to start tinkering with the servos and configure them for the blinds that I have coming in.

Main Project: Milestone Two

Main Project: Milestone One

Starter Project