IR Signal Translator

Basic Setup

The device consists of an ESP32 development board connected to an infrared receiver, which captures signals from the Firestick remote, and an infrared LED, which transmits signals to the projector.

Capturing IR Signals

Before developing the signal translation firmware, I first needed to capture the exact IR codes used by both remotes. To achieve this, I wrote a simple ESP32 program that continuously listened for incoming IR signals and printed their hexadecimal values to the serial monitor. By pressing each button on both remotes and recording the output, I was able to identify the specific signals required for translation.

            
#include 
#include 

const uint16_t RECV_PIN = 15;  // IR receiver connected to GPIO 15
IRrecv irrecv(RECV_PIN);       // Create an IR receiver object
decode_results results;        // Store received IR data

void setup() {
    Serial.begin(115200);  // Initialize serial monitor
    irrecv.enableIRIn();   // Start the IR receiver
}

void loop() {
    if (irrecv.decode(&results)) {
    Serial.print("IR Code received: ");
    Serial.println(results.value, HEX);  // Print the received IR code in hexadecimal format
    irrecv.resume();  // Prepare for next signal
    }
}     
         

Solving Signal Interference

One issue I initially overlooked when designing this device was IR signal interference. Both the Firestick remote and the signal translator emit IR signals simultaneously, which can overlap and create unreadable or meaningless signals. As a result, neither the projector nor the ESP32 could reliably interpret commands, rendering the remote unusable.

My first solution was a firmware tweak, adding a short delay between receiving a signal and transmitting the translated one. This allowed time to release the remote button, cutting out interference. While this somewhat worked, it made repeated button presses (such as adjusting volume) frustratingly slow, requiring users to press, release, wait, then press again.

To eliminate interference without introducing delays, I came up with a physical solution. I positioned the IR LED from the translator directly onto the projector’s IR receiver and covered it with aluminum tape. This setup ensured that:

• The projector only receives signals from the translator, preventing interference.
• The translator only reads signals from the remote, filtering out unwanted IR noise.

This approach maintained smooth operation, allowing the Firestick remote to function seamlessly without lag or missed commands.

New Problem: The Projector Remote No Longer Works

While this setup successfully eliminated interference, it introduced a new issue—the projector's own remote could no longer be used, for adjusting settings, since its signals were blocked by the aluminum tape.

To solve this, I modified the firmware to act as a relay, allowing the translator to forward any unrecognized signals directly to the projector. This ensured that:

• The Firestick remote still worked seamlessly with the projector.
• The projector's original remote could still be used for manual control.

Key logic for the relay system:

                   default:
                       Serial.println("Sending other signal directly to projector");
                       irsend.sendNEC(results.value);
                       break;
                   

Sleep Timer

With the translator now working well, I started thinking beyond just relaying and translating signals. Since the ESP32 had control over the projector, I decided to add a sleep timer to automatically turn it off after a period of inactivity, preventing it from staying on all night if I fell asleep.

At first, the implementation seemed simple: set a timer, reset it every time a button is pressed, and if no input is detected for a set period (e.g., one hour), send the power-off signal.

Problem: No Dedicated On/Off Signals

The projector only has a single power button, rather than separate on and off signals. This meant the ESP32 couldn't simply send a power command after an hour, as it might accidentally turn the projector on instead of off.

To track the projector's state, I initially planned to use a firmware-based boolean toggle, switching its state whenever the power signal was sent. However, this approach had a major flaw: the projector requires two power-off presses—one to trigger shutdown and another to confirm. If these presses happened too quickly, the projector wouldn't register the second press, potentially leaving the ESP32 out of sync with the actual power state.

Solution: Hardware-Based State Tracking

To ensure reliable tracking, I found a better approach: the projector has a USB port that only receives power when it is on. I connected a USB cable to a voltage divider to step the voltage down to 3V, then fed it into one of the ESP32's GPIO pins. This allowed the ESP32 to accurately detect when the projector was powered on, making it easy to implement the sleep timer logic reliably.

Key logic for the sleep timer:

                // Check sleep duration and projector power state
                now = millis();
                if (((now - startTime) >= autoOffDuration) && digitalRead(4) == HIGH) {
                    Serial.println("Sleep timer reached, powering off.");
                    irsend.sendNEC(0xFF15EA); // Send first power off signal
                    delay(10000); // Wait 10 seconds
                    irsend.sendNEC(0xFF15EA); // Send second power off signal
                    startTime = millis(); // Reset sleep timer
                    delay(5000); // Further delay to avoid errors
                }
                
               

Future Improvements

There are several ways this IR translator could be expanded to add more functionality and automation, making it even more versatile and user-friendly.

Smart Home Integration

Connecting the ESP32 to a smart home system would enable voice control through Alexa or Google Assistant, allowing commands like turning the projector on and off, adjusting the volume, or even setting the sleep timer. This would eliminate the need for physical remotes and make the system seamlessly integrate with existing home automation setups.

Custom Remote Mapping

A learning mode could be implemented, allowing users to program custom remote buttons without modifying the firmware manually. This would make the device more user-friendly, enabling support for a wider range of devices without requiring additional coding. Such a feature could also open possibilities for commercialization, making the translator a more widely applicable consumer product.

Mobile App Integration

Integrating the translator with a mobile app would provide a simple interface for adjusting settings such as sleep timer duration, signal delay intervals, or even manually triggering IR commands. This would offer more flexibility and convenience, eliminating the need to reflash firmware whenever adjustments are needed.