Water-logged stretches under urban flyovers regularly hide deep potholes that endanger pedestrians and vehicles. I want a compact, rugged device that can sense the depth of those hidden holes in real time and immediately broadcast an easy-to-read warning on two fronts: the existing overhead/roadside display network already installed at the site and a small screen that ships with the unit itself. Here is the essence of what I need done: • Engineer a depth-detection module that works reliably even when the road surface is submerged. Ultrasound, radar, LiDAR or a hybrid approach is fine as long as readings remain accurate despite murky water, moving traffic, and vibration. • Design the electronics, firmware and housing so the unit withstands rain, grit, vibration and an occasional knock from maintenance staff. IP-rated waterproofing is essential. • Build or specify a minimal on-device display (simple LED matrix or low-power LCD) that flashes the measured depth and a colour-coded danger level. • Create a data interface that pushes the same alert to the flyover’s existing display controllers with minimal latency. If those controllers speak a common protocol (e.g. Modbus, RS-485, CAN or HTTP), integrate directly; otherwise provide a simple gateway. • Supply schematics, PCB/Gerber files, firmware source, enclosure CAD and a concise integration manual. • Deliver a tested, working prototype quickly—I’m aiming for an ASAP turnaround, so please outline how many days you’ll need for each stage (design, fabrication, firmware, bench test, on-site test). Acceptance criteria 1. In on-site tests the device must detect potholes at least 10 cm deep with ±1 cm accuracy while submerged under up to 20 cm of water. 2. Warning appears simultaneously on both the built-in screen and the existing flyover display within two seconds of detection. 3. System operates for a minimum of 72 hours on continuous power or eight hours on internal backup battery without reboot. If you have prior experience with roadway IoT sensors, waterproof enclosures, or traffic-sign integrations, you’ll be able to hit the ground running. Let me know which sensing technology you propose and how fast you can ship the first prototype.