Lost in the Sands
After the dust storm, Zorin and Althorn’s rover was finally stuck in the sands of the Martian plains. Thin layers of sand had seeped into the mechanisms, and the control system failed. They tried to contact the base, but the alien communication systems that had functioned before were now silent as well. All electronic devices, including the transmitters, were affected by an unknown glitch.
“We need to come up with something fast, or no one will find us,” Zorin said grimly, inspecting the control panel.
“We can use Arduino, ” Althorn suggested, pulling a small kit from the toolbox that he always carried for experiments. “A piezo speaker can emit a sound signal. If we choose the frequency correctly, the signal can be heard even at a great distance.”
“You want to build a system out of that?” Zorin asked in surprise. He had seen Althorn experiment with Arduino many times, but he never thought this small board could save their lives.
“Yes, it’s possible, ” Althorn replied. “I’ll use a piezo speaker, just like in our experiments at the base. Sound can be generated at the required frequency and duration. A piezo element is capable of generating a fairly loud sound. If the base doesn’t hear us over the radio, perhaps it will catch a sound signal.”
They began working together, assembling the circuit on a breadboard. Althorn connected the Arduino to the piezo speaker directly to Pin 8. Aiming the system outward, they programmed the device to emit short, sequential signals, similar to Morse code.
“There, ” Althorn said while programming the device. “If the signal is powerful enough, they will hear us and understand it’s a distress signal.”
The situation was becoming increasingly tense. Althorn had been experimenting with the Arduino for several hours, trying to get the piezo speaker to generate enough power for the base to hear. But things were not going as planned. The sounds produced by the circuit were too quiet, and the frequency remained far from what was needed for a distress signal. Althorn nervously checked the program and started over, but the result was the same.
“It’s not working, ” Althorn said with frustration, setting the soldering iron aside. “We’re just wasting time.”
Zorin, watching his attempts, suddenly suggested: “Let’s try connecting a potentiometer. It will help regulate the volume. Maybe by increasing it, we’ll achieve the desired effect.”
Althorn thought for a moment, then agreed. They connected the potentiometer to the breadboard, linking it to an analog input on the Arduino. First, they programmed it to change the volume of the piezo speaker by controlling the amplitude of the sound signal. Turning the potentiometer knob, Althorn gradually increased the volume until the sound reached maximum power.
Despite this, the signal was still not clear enough. Then Zorin suggested another experiment: use the same potentiometer, but now to control the frequency of the sound. They reprogrammed the circuit so that the pitch changed depending on the rotation angle of the knob. Now the speaker emitted more varied signals, and with each adjustment, the frequency moved closer to one that could be detected at a great distance.
It took a few more hours, but eventually, Zorin was able to tune the device to the correct frequency and signal amplitude. Finally, after many attempts, the sound signal became powerful and regular enough to be heard back at the base.
“This should work, ” Zorin said, stepping back from the board. “If the base is tuned to pick up sound, they will hear our signal.”
Now, all they could do was wait. After a few minutes, the piezo speaker began to emit a loud, piercing sound, repeating at intervals. They waited. All they could do was hope the base would hear.
On the other side of the planet, Lirania and Melia, on duty at the base, heard a faint sound in the speakers. It was unlike the usual noise of the communication system. Lirania listened intently and then, after some manipulations with a sound analyzer, realized it was a distress signal.
“It’s them, ” she said, glancing at Melia. “Get ready, we’re going.”
They quickly prepped the second rover and set out. The system guided them by the faint sound vibrations emanating from the device built by Zorin and Althorn. After several hours, they saw the silhouette of the rover in the distance with two figures standing nearby, and the sound signal grew louder and louder.
“We made it, ” Melia said with relief, signaling Lirania to stop the rover.
Now, together, they could repair Zorin and Althorn’s rover and return to the base.