MicMinder
Clarkson Senior Capstone
An electronic microphone sleeve that uses proximity, motion, and orientation sensors to provide real-time visual and haptic feedback, helping speakers maintain consistent microphone technique and audio quality.
What’s The MicMinder?
Live events rely heavily on amplified audio, but producing consistently clear sound is dependent on how the speaker holds the microphone. During panels, university events, assemblies, and other events where microphones are passed between speakers, inexperienced users frequently hold the microphone too far away, point it away from their mouth, or move it while speaking. These changes can alter the level, frequency response, and consistency of the audio reaching the sound system. Directional microphones with a cardioid or supercardoid pickup pattern are particularly sensitive to changes in placement; moving a microphone relative to its sound source can change both its pickup and tonal characteristics.
This project focused on developing a device that could teach proper microphone technique without requiring an audio professional to continuously correct each presenter. Rather than modifying the microphone itself or requiring presenters to use a specialized headset or stand, MicMinder is a removable electronic sleeve that attaches to any handheld vocal microphone. The device monitors the microphone's proximity to the speaker, its orientation, and how quickly it is being moved. It then provides feedback directly to the user through an RGB LED and haptic vibration. The result is effectively a closed-loop feedback system: the speaker changes their microphone technique, the sensors detect the change, and the device immediately communicates whether the new position is acceptable.
Design Challenges
The fundamental design challenge was determining what "correct" microphone technique meant in a way that could be measured electronically. We identified three primary variables. The first was proximity: the microphone needs to remain within an appropriate distance of the presenter for its intended pickup pattern. The second was angle: the microphone capsule needs to remain directed toward the sound source rather than being pointed away from the presenter. The third was stability: excessive movement can change the relationship between the microphone and speaker and can also introduce handling noise. These variables correspond to the three major sensing functions of MicMinder.
One of the more important design decisions what the MicMinder defined as an acceptable speaking position. Different speakers have different heights, postures, and natural ways of holding a microphone. Instead, the system establishes a personalized reference point each time the microphone changes users. When a speaker raises the microphone into position, they press the reset button. The microcontroller inside the microphone records the current distance and motion/orientation measurements as the user's "home" position. This creates a local reference against which subsequent measurements can be compared.
Physical Design
The MicMinder consists of a plastic shell with a central shaft cut out of the center.
The microphone itself only needs to be installed into the MicMinder housing once. A foam-lined channel in the shell grips the microphone body, while the positioning of the shell ensures that the distance sensor has an unobstructed view toward the speaker's face. When the microphone is passed to another speaker, the hardware does not need to be adjusted; the new speaker simply holds the microphone where they want it and presses the reset button to establish a new reference position.
Electronics Design
The electronics were built around an Adafruit Feather RP2040 microcontroller. The RP2040 serves as the central processor, collecting data from the various sensors, comparing those measurements against the user's calibrated position, and controlling the feedback devices. During prototyping, an LSM6DSOX 6-DoF inertial sensor, a VCNL4010 proximity sensor, two discrete tilt sensors, and an Adafruit NeoPixel RGB LED were used. A vibration motor was also incorporated into the production design, although supply-chain limitations prevented us from installing one in the first electronics prototype.
The sensors communicate with the microcontroller through several different interfaces. The LSM6DSOX and VCNL4010 communicate with the RP2040 over the I²C bus, allowing multiple digital sensors to share the same communication interface. The two tilt sensors instead connect directly to analog inputs on the microcontroller. This gave us a relatively simple electronics architecture while allowing the different sensors to perform specialized jobs.
Power management was another consideration because a device attached to a microphone should not require a separate power switch or demand attention from the user. Two tilt switches are used to detect whether the microphone is in its normal resting or performance orientation. When the microphone is raised, the change in orientation automatically wakes the device. When it is placed on its side after use, the system waits briefly and then enters its automatic shutdown state. This allows the device to behave more like a passive microphone accessory than another piece of equipment that the user must remember to operate.
Once the microphone has been calibrated, the microcontroller continuously monitors the sensor inputs. Rather than treating every small change as an error, the software uses multiple levels of feedback. When the microphone remains within the acceptable calibrated range, the RGB LED stays solid green. A minor deviation causes the LED to flash yellow, providing a subtle indication that the speaker should adjust their technique. If the microphone remains significantly out of range, the LED flashes red and the vibration motor activates. This gives the speaker a second, tactile indication without requiring them to look away from the audience to check the microphone.
The system therefore functions as a simple state machine. The device begins in an off state, transitions to an active state when the microphone is raised, and then waits for the user to establish a home position. Once calibrated, it operates in an in-range state until one or more sensors indicate a deviation. A minor deviation transitions the system into a warning state, while a sustained or more significant deviation transitions it into an out-of-range state. If the microphone remains out of range for an extended period, the system can eventually shut itself down to conserve battery power. The timing of these transitions is controlled by a configurable variable, allowing the sensitivity of the feedback to be adjusted rather than forcing the device to react to every instantaneous movement.
An important part of this logic is that the device uses multiple sensors to characterize microphone position instead of relying on a single measurement. The proximity sensor establishes the relationship between the microphone and the speaker, while the inertial sensors and tilt switches provide information about orientation and movement. This allows the software to distinguish between simply moving the microphone slightly and actually using it in a way that could compromise the audio. The invention report specifically describes the multiple-sensor approach as a way of improving movement detection and providing redundancy between sensors.
Hardware Design
The electronics were developed incrementally rather than designing a production circuit immediately. Once the sensor package and communication interfaces were working, the electronics were transferred from a breadboard to a perfboard for final prototype assembly. This approach allowed us to separate the electrical debugging process from the mechanical design and avoid repeatedly redesigning the enclosure while the circuit was still changing. As this is a prototype circut, the finished thickness of the perfboard was more than the initial design of the enclosure allowed for. As such, targeted heat was used to reshape the internal geometry of the V1 prototype to fit a
The physical housing was developed in parallel using FDM 3D printing at the Clarkson University Makerspace. PLA was selected because it offered a useful balance between printing speed, surface quality, material cost, and ease of iteration. The shell was designed as two pieces surrounding a central microphone path, with foam providing the interference fit needed to accommodate the microphone while protecting its finish. The housing also incorporates the reset button, RGB LED, proximity sensor, removable bottom plate, and internal electronics.
