Problem 3: after inserting the optical module, the switch indicator light is red Reasons and solutions: the main reason is that the optical module is not compatible. You can open the operation data and check the manufacturer information of the optical module. Identify colours, measure light levels, or detect infrared radiation for smart lighting, colour sorting, or interactive projects. Compatible with Arduino UNO R4 WiFi or any Qwiic-enabled. Assuming nothing moved at your house broken line outside. Office issue or someone hit something. Could be bad Ont but very very rarely do they not see good light it's usually power issue entirely or reboot loops God bless it took them 50 days to come fix mine Mine recently went out as well. The notices referring to your personal safety are highlighted in the manual by a safety alert symbol, notices referring only to property damage have no safety alert. The QRD1114 is a half-LED, half-phototransistor, all infrared reflective optical detector. To simplify the wiring, you can use an LDR light sensor module as.