Hub sensors direct connect diy

[AndreL]

Once again I would like to consult the knowledge gurus - why?
since frsky has dropped the original line of sensors for the first gen hub telemetry, it is beginning to be a challenge of compatible replacement. After reading some information on the openXsensor, I have picked up some modules hoping that they would be compatible replacements for the original sensors. One of those is BMP280 pressure sensor, and the other is beitian 220 gps head. Although the hub could process the BMP085 I2C stream, I am guessing that the data frame is changed in the BMP280? when directly connected to the hub it just hard reads 212 and does not fluctuate with small height change at all. Would the BMP180 work?. In the openXsensor the option of use shows either BMP085, 180 or 280 (hence my assumption of comparability).
The other is the beitian module lineup. Due to the influx of ublox clones which are firmware locked, i decided to switch to a brand that the openXsensor utilizes. When connected directly, the hub didn't have any issues with the neo-6 modules, even clones, found them right away when searching for new sensors in open tx 2.1 telemetry screen is selected. But it will not detect the beitian head. Utilizing U-center the one visible difference that i see is the NEMA message output type, although nema message configuration is set the same, neo head bursts starting with $GP***, and the beitian starts with $GN***. I guess the hub is looking at the prefix? Is there a way to change output message type on the head?, u-center says that there is at least 5 different message configurations but i was not able to change it.
My last question would be pointed towards the hub - I have not seen, but is there a custom firmware for that module. since the firmware can be upgraded on the unit, can custom firmware iron out some the connectivity issues by modifying type of sensor input? STM32f arm cortex on paper seems like an impressive micro when compared to the arduino.
As always thank you in advance for your knowledge and clarification.

[MikeB]

The SPort vario FrSky now make still supports sending the hub protocol directly to a 'D' receiver.

I have an Arduino Pro Mini project that connects to SPort sensors and outputs hub protocol, see here: https://github.com/MikeBland/SportToHub. With this, you connect SPort sensors to the Arduino, then the Arduino output directly to the 'D' receiver.

There is no custom firmware for the hub itself as far as I know..

Mike

[kalle123]

'oXs_config_description.h' reads

Note : for the HUB protocol, only one oXs may be connected to the receiver (other sensors are not allowed).

It does not say

... only one oXs with only one sensor ...

br KH

[AndreL]

yes I did investigate the arduino path, so far I stayed with the hub due to its simplicity and multi input support. I have built hall rpm sensors and capacitive fuel sensors for my planes which makes it enjoyable and predictable when flying. Plug in a 5 dollar neo gps head and i was in business. This whole adventure started when I wanted to attain altitude accuracy and faster gps burst processing. For the x-receivers there is a vario with hub interface, but for the d-receivers that option is now obsolete. The arduino project is tempting and I should try it out but at the same time I have to figure out if the mini can support and keep up to at least 4 sensors. But considering that the hub can do all, its a shame that its software cannot be modified. I am more of a hardware developer, my programming skills are bit stale - hence the questions. Thanks for the help.

[AndreL]

sorry that i did not mention you Mike but you gave me that exact answer a while ago and yes I obtained few varios for my x-receivers that allow the hub to pass data through - thank you happy with that, at the moment i am trying to outfit my d-receivers.

[MikeB]

While I understand you probably need more than the one sensor, the SPort vario does still connect directly to a 'D' receiver with hub protocol.

As a completely different potential solution to the lack of hub sensors, I have firmware that replaces the standard firmware on a 'D' receiver and supports D16 mode with SPort telemetry, see here: https://www.rcgroups.com/forums/showthr ... -receivers.

The Pro Mini code supports many sensors.

Mike

[AndreL]

upgrade the old receiver, outstanding, thats a great read and stellar work - thanks Mike.

[MikeB]

To get the SPort telemetry functional, you need either a diode or a transistor on the Tx signal to make it bi-directional.
I need to post some details on that, just finding time to check thing out first. A diode (anode to Tx, cathode to Rx and use the Rx signal as the SPort signal) should be good enough generally, although a transistor (as an "emitter follower") may be needed when using many sensors. I did an initial test using a board from FrSky they sold with a diode on it to allow a FrUSB-3 (FUC-3) device to connect to the SPort.

Mike