Express LRS first time setup with ardupilot

Ground Control Software Mission Planner
1

Greetings

I am trying to use express LRS as telemetry link to mission planner on my laptop in the field. I am working on mapping projects so I don’t need to use ExpressLRS to control the plane from my radio transmiiter.

I am using

HappyModel ES900TX ES900RX ExpressLRS ( 3.2 firmware on both RX TX )
Pixhawk 2.4.8 ( latest firmware)

First of all is possible to use expressLRS directly with the laptop without the radio transmitter ?

Second, do I have to flash the RX and TX for my purpose ( telemetry in mission planner only )

The module has built in WiFi and a USB port.

So far I wired the RX correctly to telemetry 2 port on my pixhawk and connected the TX via USB cable to my radio transmitter. They are both running fine with flashing LED. Also I can see the wifi connection in my laptop for both RX and TX

I can see the com port on my laptop device manger and in mission planner as COM 6. However when I try to connect in mission planner it fails ( 30 second until it times out )

I tried both 57 bud and 115 bud for connection

Also I set in mission planner parameters:

Serial2_Protocol to 23
RSSI_Type = 3

Sorry for the inconvenience this my first time setup

2

Normally You should not see WiFi from RX. It goes to WiFi when it is not paired with TX.
You sure RX and TX are talking to eachother?

3

No I am not sure if they are linked together.
Every time I power cycle both the RX and TX. The Rx green light blinks fast after 60 seconds which means it in WiFi mode.
That what I know so far.

4
  1. You need to update both TX and RC module firmware to the current version 3.5.3+
  2. Configure and bind TX and RX.
  3. Configure the TX and RX for MAVLink operation
  4. Connect RX to serial port configured for MAVLink 2 at 460kbaud IIRC (as described on ELRS wiki)
5

Thank you for the info

6

1- I did update the firmware successfully for both of them.

2- even after flashing ,they still won’t bind. I flashed them with binding phrase in the lrs configuration.

Now for this model to the lrs configuration, i build and flashed via WiFi. I chose release 3.5.4 , device happymodel 900mhz and for device I selected happymodel ES900 RX
And also the same but for TX.

And still they are not binding no solid green light on the RX

And from mission planner I set these parameters

Configure SERIALx_PROTOCOL=2
SERIALx_BAUD=460
RSSI_TYPE=5

unfortunately they are still not binding

7

I am ssuming You have matching settings in terms of requency 868/915 and region selection.
AFAIR flashing elrs does not change model match options, so You can check that too - connect to RX and TX wifi, and open their webpage to check if model match is disabled.

I would just put it into radio and check all the settings using lua script and make sure that radios are actually talking, and then switch to mavlink starting from receiver side.

I might try tomorrow to setup something similar on my desk.

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8

I tried to set elsr in mavlink mode however it looks like TX and RX connecting only when module is actually in radio. When it is just plugged over USB - no link.

9

Thanks for your support and time

Thats unfortunate, I was planning to use it directly with a USB to my laptop.

Please let me know if find a way around.

I already contacted info@happymodel.cn regarding this issue.

Last night I flashed both RX and TX again. I put the RX in bind mode but unfortunately no connection .

1 Like
10

To follow up

I purchased a jumper t14 elrs radio.
I was able to bind the RX and TX ( RX solid green , TX solid red ) but that still did not solve my problem which is connecting to mission planner for telemetry using ELRS.

In the radio settings I turned off the internal LRS and enabled the external lrs.

All that was done while the external TX was inserted in the radio.

If I remove the external TX and connect to my laptop via USB. The TX and RX will not bind.

Please help

11

try to setup your wifi backbag to udp and choose correct port number

you will use udp after that on mission planner to connect to the tx module and get mavlink to connect.

Follow This Guide: