Money

Thirty euros to hear the sky. Then the bill grows with altitude.

Phone listener

0 EUR · app on a phone you own

RID box

~25 EUR · ESP32-S3, cable, case

Acoustic box

~50 EUR · 4 mics, ESP32, printed shell

Node with Pi 5

~150 EUR · brain plus one ear

RF node (HackRF)

~450 EUR · Pi plus a radio that actually sees 2.4 GHz

Aaronia / SPEXER cell

professional, no citizen price here

DIY interceptor

~400 EUR · 5/7 inch, net, Pixhawk class. Legal layer not included.

Five million roof nodes at 150 EUR is 750 million EUR for the listening layer, before interceptors, before labour, before the second layer. That is the kind of number a budget office can hate and a wave of ten thousand drones still cannot beat with one missile.

Fakten-Tabelle · Fact table

Hypothese

Street prices, 9 September 2026, German shop order of magnitude. No quotes, no VAT polish, no volume. Confidence: medium for hobby BOM, low for professional cells.cost page, first pass