We are using a Jeti ESC on our aircraft, and we would like to be able to log the various parameters that are sent out on the EX bus, i.e. battery voltage, ESC temperature and motor speed. The EX bus uses a single wire, but is it possible to connect this directly to one of the spare UARTs on the FMU or would some sort of hardware interface be required? Also, has any code already been developed to support this?
As to my knowledge, there is spare UART you can use, but software is missing right now. I am not familiar with EX bus but good to have it supported.
Do you have any plan on how to support it?
No! That’s why I am asking!
We also have another aircraft, that uses 4 Jeti ESCs, and I’m hoping that we can connect these to a Jeti E4 bus expander and then connect the output of this to PX4.
Would be interested to look into this. Let’s discuss on the dev call on Monday.
I looked into picking up one of these ESCs, they are really expensive ($225 is the cheapest model on the US site). They look really well built though.
We use ESCs from the Jeti Spin Pro range
The one we are currently using (Spin Pro 66) is around £80 in the UK. We are interested in being able to log the motor speed output, as this will help with our powertrain modelling.
Some information from Jeti.
Hi Lorenz. Did the Jeti EX bus thing get discussed at your Dev Call? If so, what was the outcome?
They actually have documentation! http://www.jetimodel.com/en/Telemetry-Protocol/
Is there something new on that topic?
From the hardware point of view, there is enough to connect 2.4k Ohm resistor between any RX a TX pins of spare UART.
But software seems to be a bit complicated because the EX Bus protocol contains both telemetry requests and control packets. Therefore the PX4 driver should have similar reliability as PX4 PPM signal generator and at the same time publish uorb messages with telemetry data.