Visible Light Sensor Design
Thought for 26 sec
The four DIP-switch-selectable feedback resistors are:
- Switch 1 / R1: 10 kΩ — lowest gain, best for bright light
- Switch 2 / R2: 100 kΩ
- Switch 3 / R3: 1 MΩ
- Switch 4 / R4: 10 MΩ — highest gain, best for very dim light
Use only one switch at a time. If multiple switches are ON, the resistors operate in parallel and the lowest resistance largely determines the gain. If the output saturates high, select a lower resistance.
Thought for 26 sec
Switch 1 (10 kΩ) is the switch position closest to the photodiode/sensor, not the upper board edge.
You can identify that end by the square pin-1 pad on SW1. Switches then progress toward the edge:
- 10 kΩ — closest to sensor
- 100 kΩ
- 1 MΩ
- 10 MΩ — closest to board edge
Thought for 7 sec
Looking at the board from the top/component side, with the DIP switch text readable, the switches run left to right as:
10 kΩ → 100 kΩ → 1 MΩ → 10 MΩ
So the leftmost switch is Switch 1 (10 kΩ) and the rightmost is Switch 4 (10 MΩ).
