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JHU ENGINEERING INNOVATION / INDIVIDUAL ELECTRONICS PROJECT

CircaDock.

A bedtime idea,
built in code.

Could a phone dock make the decision to put a phone down more tangible? During my JHU summer program, I developed a design that connects room conditions, a phone-presence input, and a clear sequence of feedback.

DESIGN + SIMULATION7 ITERATIONSSUMMER 2026
Read my design notebook

DOCUMENTED PROGRAM LOGIC

The program,
in six states.

  1. 01
    OffButton A starts the sequence.
  2. 02
    Check the roomRead light, sound, and temperature.
  3. 03
    Wait for the phoneRequire a docking input to continue.
  4. 04
    ReadyBlue feedback, a three-second delay, then lights off.
  5. 05
    MonitorWatch the docking input and room conditions.
  6. 06
    AlarmRespond to removal; redocking returns to the room check.

Button B is the global stop control.

THE DESIGN QUESTION

More than
another reminder.

I first considered a temperature-aware water reminder. I set it aside because another alert could be easy to ignore, and similar reminder products already existed.

The sleep-dock concept introduced a different condition: monitoring would begin only after the phone-presence input was active. This was a program rule with an alarm response, rather than a mechanical lock on the phone.

The platform was Circuit Playground Express, programmed in MakeCode. The design combined light, sound, and temperature readings with LED feedback, a buzzer, and Buttons A and B.

THE ITERATIONS

Seven versions.
A more dependable exit.

The most useful progress came from finding where the program became difficult to operate—and revising the next version around that problem.

  1. 01

    Find a starting point

    The first version had nonworking code and an incomplete set of functions.

    Shared version 1 ↗
  2. 02

    Make the docking input testable

    I repaired bugs and substituted a button input for the proposed capacitive detector, which required extra hardware and was difficult to simulate.

    Shared version 2 ↗
  3. 03

    Get the basic sequence working

    The core behavior was in place. I then considered adding temperature to the conditions checked before monitoring.

    Shared version 3 ↗
  4. 04

    Add temperature—and uncover another bug

    Temperature became an additional input, but the simulator's sound control could disappear depending on the light setting.

    Shared version 4 ↗
  5. 05

    Separate the sensor controls

    The three simulator inputs were available independently. The next problem was an alarm state that did not stop as intended.

    Shared version 5 ↗
  6. 06

    Introduce a start control

    Button A started the program, but stopping the alarm still required repeated presses.

    Shared version 6 ↗
  7. 07

    Give stopping its own control

    The final documented iteration kept Button A for starting and used Button B to stop promptly. A dependable exit became part of the design itself.

    Open the final shared version ↗

INSIDE THE NOTEBOOK

The logic,
in blocks.

Original screenshots from my design notebook. They show documented code variants, including the proposed A1 capacitive input; the iteration notes describe using a button input for simulation.

Original MakeCode blocks for state variables, sensor polling, the A1 input, and the Button B shutdown check.
Inputs and control. State variables, sensor readings, and the shutdown check at the top of the loop. Open full image ↗
MakeCode blocks for environmental checks, waiting for the phone, and the ready stage.
Before monitoring. Environmental checks and transitions through waiting for the phone and the ready stage. Open full image ↗
MakeCode alarm timing and the transition back to environmental checking when docking is detected.
Alarm behavior. Timing the light and buzzer response, and returning to environmental checking when docking is detected. Open full image ↗

WHAT THIS WORK DOCUMENTS

A control system
to keep improving.

This project documents design decisions and MakeCode iterations. It does not establish a tested physical phone detector or measured changes in sleep or phone-use behavior.

The code uses light and sound thresholds of 20 and 60 in the platform's sensor values, plus a selected temperature range of 18–25°C. These are design settings; the light and sound values are not stated in lux or decibels.

A simulated sunrise appears in the CircaDock concept summary as a further feature. It sits outside the six-state program documented here.

Read the original 7-page notebook