clock inspired – A maker turned the familiar clock-drawing test into a machine: a 3D-printed clock whose numerals are placed only on the right half and sit out of order, while a servo-driven hour hand updates the time once per hour and an ESP32-C3 syncs monthly over Wi‑Fi to s
When people talk about cognitive impairment screening. the clock-drawing test often comes up for a reason: it’s simple enough to run quickly. but revealing enough to show strain in how the brain organizes a basic task. In the test. a patient is handed a printed circle and asked to draw a clock face with the hands set to a specified time. Depending on what the drawn clock looks like, clinicians may see patterns linked to different disorders—dementia among them. In some cases, the “failed” drawing can show a particular deformity that points toward a specific issue.
That clinical logic is exactly what pushed [John Silvia] to build something stranger and more symbolic: a clock with a deliberately disordered face.
In Silvia’s clock, the numerals don’t appear across the whole circle. They’re placed exclusively along the right half of the clock and are out of order. In the original clock-drawing test. that kind of placement can be a sign of damage to the right parietal lobe—or executive dysfunction caused by dementia.
The mechanics are equally split. The hour hand is driven by a servo motor, while the minute hand is mounted on a separate clock mechanism that’s commercially purchased and installed on the left-hand side of the face. The clock’s frame and face are both 3D-printed.
Power is handled with the kind of care you only see when something has to run for months without becoming another gadget charging problem. A servo motor control board uses an ESP32-C3 paired with an RTC module. To minimize power draw, a MOSFET disconnects the servo motor from power except for the once-per-hour position update. The ESP32 also avoids constant connectivity: once per month, it connects to Wi‑Fi to synchronize to NTP time. Otherwise, it remains in a low-power state, and even its indicator LEDs are disconnected to save power.
The result is practical as well as odd. When the servo isn’t active, it draws only about 160 µA. With a set of three AA NiMH cells, the clock is designed to last about a year.
The design doesn’t stop at this one-purpose machine. Since the servo motor takes most of the power budget. reducing ESP32 power wouldn’t change much for this particular build. Still, the ESP32’s co-processor can be used for ultra-low-power projects, and Silvia points readers toward other drawing-related clock ideas.
One small gadget can’t diagnose anyone. But it can carry the texture of those tests into a new form—turning a clinical failure mode into an everyday object that runs quietly for months, all while its face looks like it’s trying to follow rules it can’t fully read.
clock-drawing test cognitive impairment dementia ESP32-C3 NTP 3D printed clock servo motor MOSFET power saving ultra-low-power IoT ESP32 RTC module
So it just… tells when you have dementia? Wild.
Sounds like a gimmick clock that judges your brain, lol. If it syncs monthly over Wi-Fi does that mean it’s gonna start spying too?
Wait I thought those tests are like writing in a notebook? Now it’s a 3D printed clock with the numbers on only one side?? That feels backwards because if someone’s right-handed they’ll still get it wrong. Like is it measuring attention or just confusing people?
They say it’s based on right parietal lobe damage, but my grandma didn’t even know what a clock was half the time and she was fine (kinda). Also the article says it updates once per hour and syncs monthly… so if it’s wrong for a month that’s not great for screening. I don’t trust it tbh, clocks always act weird anyway.