RC, photos & tech


Orangerx, OpenLRSng, Naze32 – PPM input

The Problem:

I need to activate PPM input to the Naze32 board from the Orangerx UHF running OpenLRSng. PPM input is needed so I can use RC5 pin to control some WS2812 addressable LEDs.


The solution process:

In the Cleanflight configurator, enable RX_PPM. Connect the receiver Port 6 output to the RC input pin 1 of the Naze32 board. The problem is when I do that, and switch on the transmitter (ie the PPM stream is presented to the Naze32 input), the Naze 32 seems to lag horribly. Connecting it to the configurator takes ages for the screen to refresh.

I found disabling Telemetry in the openLRSng options for the orangerx Tx module seemed to fix the problem of the Naze32 board lagging. Now I can use the RC5 pin on the Naze32 board to control the addressable LEDs (WS2812).

The only remaining issue is that appears after arming once, then disarming, I can't re-arm with completely removing power from the Naze32.




Update OpenLRSng to FW 3.8

Problem: Trying to update the OpenLRSng firmware to version 3.8 failed to due error message "PSP Command Not recognised" after trying to connect the USB to serial adapter to the Tx module

Solution: Flashed the Tx module with the bootloader via the Arduino IDE and USBasp. On doing this I was getting another error message "AVRDUDE: Warning: cannot set SCK period". After trying driver / firmware updates to the USBasp and not being able to solve this error message, i found it didn't really matter after trying a firmware update to 3.8 and it worked anyway!


“Start message not received within 10 seconds, disconnecting”

The Problem:

Trying to use the openLRSng Configurator app and connect to my OrangeRx Open LRS 433MHz Transmitter 1W just wouldn't connect and keeps reporting the error "Start message not received within 10 seconds, disconnecting"

The Solution:

  1. Connect your 3.3V FTDI USB to serial adapter to the pins inside the Tx module. At a minimum you need Gnd <-> Gnd, Tx <->Rx, Rx<->Tx connected.
  2. Make sure the Vcc pin is disconnected.
  3. Install the Tx module in your transmitter. I'm using a Taranis.
  4. With the transmitter turned off, advance the throttle to half. This stops power to the Tx module*.
  5. In the , openLRSng Configurator app enable the auto-connect check box next to "Connect".
  6. Turn the Tx turned on.
  7. Plug in the USB to serial FTDI.
  8. Wait until you see "Serial port successfully opened with ID: #"
  9. Pull the throttle down so the Tx initialises.
  10. There should be a couple of beeps and the configurator continues to connect.

Now you can configure your openLRSng Tx and Rx modules all via the Google Chrome Configurator and even use the Spectrum Analyser function.

* I'm not sure if other transmitter brands have the feature where power isn't applied to the Tx module until the throttle is at zero. I found the timing was important between connecting the USB and activating the Tx. With the Taranis it seemed to be much easier by having the Transmitter in the on state but with throttle up, as soon as the "connecting" message appeared, pull the throttle and it connected.

I did manage to connect without using the throttle up trick but only once and I couldn't get it to do it again. I read a post on rcgroups where a guy said it took him 20 tries before it would connect.


avrdude: stk500():not in sync: resp=0x00

The Problem:

Trying to flash the Hobbyking  OrangeRX Open LRS 433MHz Transmitter 1W ( JR Compatible) with openLRS produced the error "avrdude: stk500():not in sync: resp=0x00" in the Arduino IDE.

The solution:

Buy a 3.3V USBAsp board and following the guide here, flash the bootloader to the board. Once the bootloader was installed, the openLRS firmware uploaded without any errors.


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