Many airspeed sensors for small UAVs have the pitot tube and airspeed sensor connected via flexible silicone tubes. These tubes can kink and leak and ruin a good day of flying. They also occupy precious space.
This project aims to fit a tiny ARM processor and sensors inside a small, 3D printed pitot-static probe. The probe will have a digital interface and there will be no external pneumatic plumbing. It will be an entire Air Data Computer inside a probe! All for less than $25 worth of parts.
The ADC-Probe will contain a STM32F100C8 processor and two LPS25H pressure sensors. The sensors will measure both ambient air pressure + temperature and ram air pressure + temperature. It will then calculate indicated airspeed, true airspeed, altitude and temperature. A flight computer will be able to read from the ADC-Probe via UART or I2C. To maintain backwards compatibility with existing sensors, it will also provide an analog voltage that represents true air speed.
I've finally complete 3D models for the ADC-Probe. After several rough drafts, I decided to go with a simple aerofoil shape instead of a probe. I found the whole assembly can be made much smaller and lighter this way. This image shows the assembled probe with both pitot and static air pressure ports. This design is only 34mm high and about 40mm long.
The probe is divided into two 3D printable parts. The top part will contain the pitot pressure sensor. This pressure sensor will be mounted on a PCB that measures only 5x10mm. The wiring will go through the hole in the center of the lower part to the main PCB. The hole will then be sealed up with epoxy putty (or something).
Pitot air will enter through the hole in the front of the probe. Static air will be free to move through the port on top. The peg hanging off the upper part is hollow and static air is free to travel through it to the main PCB.
The two parts will be glued and sealed with RTV silicone thinned with toluene.