I love Colonel Panic's Oui-Spy. I had a spare ESP32-S3 and wanted a case that could hang off my backpack and hold a charge. Mine doesn't look nearly as cool as Colonel Panic's, but it was cheap, easy to print, and holds the parts plus a battery without needing a PCB. It fulfilled all my design requirements. I'm also just proud to have designed something that functions for what I need.
Trial & Error
The first couple of redesigns were all about getting the lid and body to fit together. What I settled on was four pegs on the body and four holes in the lid. If I were to redesign it, I'd play around with different closures. Right now the pegs are fitted with super glue and called good, but that means I have to break it to get back in. Inconvenient.
After that, I focused on getting space between the antenna and the battery. Originally I wanted it perpendicular to the bottom and in its own shelf, but that made the body too wide. Since I was already attaching the speaker to the lid, I made a shelf for the antenna there too, with a thin slit to peek out. I don't love this, since it also limits taking the case apart.
When everything fit, I sealed it up. The battery was snug and nothing rattled around. Yay! Then I charged it up and took it with me on errands to test it out. New problem unlocked. When the charge gets low, it gets stuck in a brownout cycle and beeps constantly. It was not fun explaining to the doctor that yes, my pocket is beeping, and no, I cannot make it stop, and I am very sorry.
When I got home, I cracked the case open and wired in a spare switch. It only needed a small modification to let the switch stick out. Since then, it's worked wonderfully. The switch has to be on for it to charge, but otherwise it hangs off my backpack and does its work. Paired with an app on my phone, it handles all my wardriving and scanning needs. I still plan to rework some of the internals later, but in the meantime I'm pretty pleased with this first attempt.
Running
The original Oui-Spy required pairing with a Wi-Fi network to access logs. I prefer lukeswitz's fork, oui-spy-unified-blue, which pairs to an Android app instead. From the app I can scan for nearby Wi-Fi networks and Bluetooth devices, or turn on Flock camera detection so the device and app alert me when one's nearby. It can also detect drones, Unitree robots, and foxhunt other devices. I haven't explored the last three, but I've collected a fair bit of Wi-Fi and mapped a fair number of Flock cameras. I'm pretty happy with the results.
My Build
- ESP32-S3 - $9/unit in a pack of 3 ($27)
- 3.7V 750mAh Rechargeable LiPo - $16
- Power Switch - $4/switch in a pack of 2 ($8)
- Speaker from an M5 Atom Voice - I'll have to find one comparable
- 3D printer and PLA
- Calipers, soldering iron, solder, heat gun, shrink tube
