Docs  /  When it doesn't work

You've checked the wiring three times and it still doesn't work — try a photo instead

The code looks right. The wiring, read back against the diagram line by line, looks right. Nothing happens. This is exactly the situation a photo solves faster than another read-through — because some mistakes are invisible in a description and obvious in a picture.

What you're seeing

You've gone through the wiring diagram against your actual breadboard, pin by pin, more than once. On paper it matches. The code uploads without an error. And still — the LED doesn't light, the sensor reads nothing, the motor doesn't turn.

Why a checklist can miss what a photo catches

A written wiring check compares your breadboard against a description, one connection at a time — and it's genuinely easy to read "connected to pin 7" as true when the wire is actually seated one row off, or in the neighbouring column, on a breadboard where rows aren't always where they look like they should be. Some of the most common real mistakes are spatial, not logical:

• A wire in the row next to the one it needed — breadboards make this an easy one-row slip.
• A component installed backwards — an LED's flat side or longer leg, an electrolytic capacitor's polarity, a diode's banded end.
• A part that's the wrong value or wrong physical part entirely, sitting where the right one should be.
• A wire that looks seated but isn't fully pushed into the rail.

None of these show up in code, and describing your wiring in words to check it just re-describes the same mistake you already made — you already believe the wire is in the right place, or you wouldn't have put it there.

What to do instead

1. Take one clear, well-lit photo of the whole breadboard

   Natural light or a bright room light, camera held directly above rather than at an angle, and the full board in frame — not a cropped close-up of just the part you suspect.

2. Photograph it as it actually is, not tidied up

   Don't "fix" a wire you think might be wrong before the photo. The mistake you can't see is exactly what the photo needs to catch.

3. Upload it to Soldr and describe what should be happening

   A short note — "the LED should light when the button is pressed, nothing happens" — gives it the same context you'd give a person looking over your shoulder.

4. Compare what it flags against the physical board directly

   If it names a specific row or component, look at that exact spot before touching anything else.

Letting Soldr do it

Photograph your breadboard and Soldr reads the picture to help spot what's wrong — the same way a second pair of eyes looking at your actual build would, rather than at your description of it.

A worked example

A common first project: an Arduino Uno, an LED, and a pushbutton — press the button, the LED lights. If it's built correctly and still doesn't respond, the classic invisible-in-a-checklist cause is the LED itself installed backwards. LEDs only conduct one way; reversed, no current flows and nothing lights, even though every wire is in the "correct" hole.

If a photo still doesn't resolve it

• Take a second photo closer to the specific area it flagged — good lighting on just that section, still showing enough surrounding wiring for context.
• If the board looks correct in the photo too, the fault may be in the code rather than the wiring — pair the photo with your actual serial output for a fuller picture.
• Still stuck? Describe the exact behaviour you expected versus what actually happens, alongside the photo — the more specific the description, the more useful the diagnosis.