Whirlybird/RS41

Documenting a particular fork in this where the focus is integration via serial communications with Vaisala RS41 Radiosonde Weather Balloon Sensor Payload for details on the overall project see the main page Whirlybird.

Expanding ESP32-S3 capabilities with RS41 Radiosonde integration utilizing UART communications. One proof of concept TEST prototype has been constructed using point to soldered connections. The current BETA is being constructed using a modified 10 conductor 1mm spaced flat ribbon cable and 2x5 2mm IDC connector. This makes for a "plug-able" adapter between the sonde and main PCB. The position and connections utilized are an interim test of developing a custom M.2 Key E form factor adapter.

BETA pictured above and first demo'd at Mountain View Reverse Engineering October 2024. Note that the sparkle infused hot glue on the M.2 connector does not actually attache the RS41 Radiosonde. Only the connector is secured to the Whirlbird PCB in lue of a M.2 adapter board and allows the sonde to be hot swapped without any modifications, soldering or other connections.

TEST utilizes the regulated 3v3 power directly to the sondes MCU and a GPIO expander port that enables a sink to ground for reset. BETA is experimenting with supplying 4v7 to the battery connection so the sonde can power itself from integrated voltage regulators.

Connector Pin Out

This is the mapping to a IDC flat ribbon cable with the red stripe indicating Pin 1.

GROUND
SWDIO
SWCLK
RESET
BATTERY
BUCK/BOOST
3 VOLT
TX
RX
GROUND

Sample output via serial of sensor reading with the additional RS41-SGP barometric pressure sensor module.

# (S)ensors
RH:  41.65 RHtu:  31.19 Trh:  31.24 T:  26.24 Tref:  33.38
Tmcu:  31.44 C:  47.58 Rt: 1138.87 Rts: 1097.28 Tp:  0.0624 Cp:  0.3628 
Pressure: 1000.49 PressureT(NTC): 31.95

(Changed the IO Expander to control the ground to RS41 rather than RESET via Q1. This totally fails and likely overloads the transistor. Unusable in this configuration unless powered directly from battery terminals.)

(Connecting to a via after scratching off soldermask. Accidentally exposed part of the ground plane and covered with kapton tape. Hot glue for stability.)

(https://www.tag-connect.com/product/tc2050-idc-tag-connect-2050-idc)