Many car audio enthusiasts integrate Digital Signal Processors (DSPs) like Mini DSP to fine-tune their sound systems. However, achieving seamless volume control can be tricky, especially when using HDMI fixed level outputs from head units. If you’re facing the challenge of programming a car remote to manage your Mini DSP volume, you’re in the right place. This guide explores how to program a remote, troubleshoot common issues, and potentially create your own solution using Arduino.
One common hurdle is that Mini DSP units often rely on IR (Infrared) remote control for volume adjustments, lacking hard-wired volume control options in certain configurations. Users often attempt to program universal TV remotes, but frequently find that while the programming seems successful, the remote fails to actually control the Mini DSP volume. This article delves into a practical approach, inspired by a user’s experience, to tackle this problem head-on.
Understanding the Challenge: IR Remote Programming for Mini DSP
The core issue lies in the compatibility between universal remotes and the Mini DSP’s IR learning system. While Mini DSP software allows programming various IR remote commands, successful programming doesn’t always translate to functional volume control. One user discovered that a Cambridge Audio soundbase remote was an exception, successfully programming and controlling the volume. This success provides a valuable clue: the issue might not be with the Mini DSP learning process itself, but rather with the IR signal characteristics of different remotes.
Decoding a Working Remote Signal with Arduino
To replicate the functionality of a working remote, like the Cambridge Audio remote, an Arduino microcontroller can be used to capture and then re-transmit the IR signals. By using standard IR libraries with Arduino, you can record the specific signals for “volume up” and “volume down” commands from a working remote. In the example provided, the following codes were captured from the Cambridge Audio remote:
- Volume Up: 0x2F5708F
- Volume Down: 0x2F5C03F
These hexadecimal codes represent the unique IR signals that the Cambridge Audio remote sends for volume control. The next step is to use these codes to program a custom remote using Arduino.
Building a DIY Car Remote with Arduino
An Arduino can be programmed to send these captured IR codes, effectively creating a custom car remote for Mini DSP volume control. The following Arduino code demonstrates how to send the NEC protocol codes for volume up and volume down using push buttons:
#include <IRremote.h>
IRsend irsend;
const int button1 = 4; // Button for Volume Up
const int button2 = 5; // Button for Volume Down
const int button3 = 6; // Optional Button
void setup() {
pinMode(button1, INPUT);
pinMode(button2, INPUT);
pinMode(button3, INPUT);
}
void loop()
{
if (digitalRead(button1) == HIGH) // Volume Up Button Pressed
{
delay(50);
irsend.sendNEC(0x2F5708F, 32); // Send Volume Up Code (NEC Protocol)
delay(200);
}
if (digitalRead(button2) == HIGH) // Volume Down Button Pressed
{
delay(50);
irsend.sendNEC(0x2F5C03F, 32); // Send Volume Down Code (NEC Protocol)
delay(200);
}
if (digitalRead(button3) == HIGH) // Optional Button (Example RC5 Protocol)
{
delay(50);
irsend.sendRC5(0x820, 32); // Example: Send RC5 Code
delay(200);
}
}This code sets up push buttons connected to Arduino pins. When a button is pressed, the Arduino sends the corresponding IR code using the IRsend library. The sendNEC function is used with the captured codes, assuming the Cambridge Audio remote uses the NEC protocol. The optional third button and sendRC5 function are included as an example and might not be necessary for basic volume control.
Troubleshooting: Why Your Programmed Remote Might Not Work
Even after successfully programming the Mini DSP with the Arduino-generated IR signals, you might still encounter issues where the volume doesn’t change. Here are a few potential reasons and troubleshooting steps:
- Protocol Mismatch: The Mini DSP might be expecting a different IR protocol than what you are sending (NEC in the example). While the Cambridge Audio remote might use NEC, other remotes might use different protocols like RC5, RC6, or others. Experiment with different
irsend.sendfunctions (e.g.,sendRC5,sendRC6) if NEC doesn’t work. - Code Accuracy: Double-check that the captured IR codes (0x2F5708F and 0x2F5C03F) are accurately transcribed in your Arduino code. Even a small error can prevent the signal from being recognized. Re-record the codes to ensure accuracy.
- IR LED Strength and Alignment: Ensure the IR LED on your Arduino setup is sufficiently strong and properly aligned with the Mini DSP’s IR receiver. Test the LED’s functionality by viewing it through a digital camera or phone camera – you should see a blinking light when the Arduino sends a signal.
- Timing and Delays: While the provided code includes delays, subtle timing differences in the IR signal might matter. Experiment with slightly adjusting the delays in the Arduino code, although this is less likely to be the primary issue compared to protocol or code accuracy.
- Mini DSP Learning Limitations: In rare cases, the Mini DSP’s IR learning function might have limitations with certain types of IR signals. If you’ve exhausted other troubleshooting steps, consider reaching out to the Mini DSP support forums again, providing detailed information about your Arduino setup and the codes you are using.
Conclusion: DIY Volume Control is Achievable
Programming a car remote for Mini DSP volume control, especially with HDMI fixed level outputs, can present challenges. However, by understanding IR protocols, utilizing tools like Arduino for signal capture and transmission, and systematically troubleshooting potential issues, a DIY solution is often achievable. By replicating the signals of a working remote and carefully implementing them in a custom Arduino-based remote, you can regain convenient volume control in your car audio system. Remember to double-check your codes, experiment with protocols if necessary, and ensure proper hardware setup for successful IR communication.
