I have a Happymodel EP1 receiver and Radiomaster Pocket radio which seem to be connected because of a solid green light on the receiver (only when radio is on, otherwise slow blinking light which means connecting). However there is no stick movement. I’ve double checked that uart 2 is what the tx and rx is connected to on the FC and that tx goes to rx and vice versa. I also did the whole update firmware process with the binding phrase on ELRS and both the transistor and receiver are on version 3. I can’t tell why it won’t work, does anyone have any suggestions?

Check to make sure "model match" isn't enabled.

Where would I find that, in radio settings or betaflight? Sorry I’m a bit new to this. :)

If you are getting a solid green LED then the transmitter and receiver are binding. If you had model match enabled and the receiver model number didn't match the one one the transmitter was expecting then it wouldn't even bind and you wouldn't even get a solid green LED. Likewise with the binding phrase. If there was a mismatch you wouldn't even get a sold green LED "bound" status.

It's more likely to be a Betaflight settings or a wiring issues between the receiver and the FC.

Can you please run the "dump", "diff all", and "status" commands in the Betaflight Configurator CLI tab and copy/paste the results back here.

Please also post some good clear photos of the actual wiring and connections between your receiver and the flight controller.

(27-Mar-2024, 06:55 PM)SnowLeopardFPV Wrote: ... If you had model match enabled and the receiver model number didn't match the one one the transmitter was expecting then it wouldn't even bind and you wouldn't even get a solid green LED. ...

This has not been my experience with elrs 3 when the passphrase is set on both sides but Model Match is enabled on only one. Configured like this, my HM elrs receivers DO connect to the tx (I get signal strength bars on my radio display) but do not pass control input to BF.

I had this happen just last night which is why I suggested he check it. My HM Fyujon rx/vtx combo came with elrs v3.0.1 and Model Match enabled. I first used the rx wifi interface to set the bindphrase and it connected right up to my tx (v3.3.0) as expected... No inputs on BF rx page though... Been here before a couple times... Go back to the rx wireless interface and look for Model Match... Oops, it's checked... Uncheck... BF inputs appear.

I've only had happymodel receivers default to this behavior with Model Match enabled though. Maybe other receivers or elrs versions behave differently?

Here's another possibility from the official elrs support for happymodel receivers: https://www.expresslrs.org/quick-start/r.../hmep2400/

Quote:NOTE:
There are Flight Controllers that will pull the RX pads LOW which will put the ESP-based receivers into Bootloader Mode unintentionally. A solid LED light on these receivers even with the TX module off is a sign they are in Bootloader Mode. If this is the case, rewire the receiver to a different UART.

(27-Mar-2024, 06:55 PM)SnowLeopardFPV Wrote: If you are getting a solid green LED then the transmitter and receiver are binding. If you had model match enabled and the receiver model number didn't match the one one the transmitter was expecting then it wouldn't even bind and you wouldn't even get a solid green LED. Likewise with the binding phrase. If there was a mismatch you wouldn't even get a sold green LED "bound" status.

It's more likely to be a Betaflight settings or a wiring issues between the receiver and the FC.

Can you please run the "dump", "diff all", and "status" commands in the Betaflight Configurator CLI tab and copy/paste the results back here.

Please also post some good clear photos of the actual wiring and connections between your receiver and the flight controller.

I added an image of the wiring and a file with the CLI console "dump", "diff all", and "status" information as there were too many words to fit into the post. What do you think could be causing the issue?

(27-Mar-2024, 07:58 PM)drumgod Wrote: Here's another possibility from the official elrs support for happymodel receivers: https://www.expresslrs.org/quick-start/r.../hmep2400/

It isn't in bootloader mode because the receiver light goes back to slowly blinking if the transmitter/radio is off.

(27-Mar-2024, 07:41 PM)drumgod Wrote: This has not been my experience with elrs 3 when the passphrase is set on both sides but Model Match is enabled on only one. Configured like this, my HM elrs receivers DO connect to the tx (I get signal strength bars on my radio display) but do not pass control input to BF.

I had this happen just last night which is why I suggested he check it. My HM Fyujon rx/vtx combo came with elrs v3.0.1 and Model Match enabled.  I first used the rx wifi interface to set the bindphrase and it connected right up to my tx (v3.3.0) as expected... No inputs on BF rx page though... Been here before a couple times... Go back to the rx wireless interface and look for Model Match... Oops, it's checked... Uncheck... BF inputs appear.

I've only had happymodel receivers default to this behavior with Model Match enabled though.  Maybe other receivers or elrs versions behave differently?

My model match on the radio was already off so that doesn't seem like the problem.

Don't see anything wrong in your settings, and your wiring seems correct (assuming you have RX to TX and TX to RX). I don't know if the soldering is causing the issue, but I would suggest resoldering in anycase. The exposed wires are too long, they could cross and short out in a crash or if you shrink wrap/twist them. You should trim down the wire ends so there is very little exposed wire extending beyond the solder joint. It is hard to make out from the photo, but also looks like solder was not flowed correctly, it looks patchy (cold solder) instead of a single shiny smooth blob/ball. If your tip is not too small and iron temperature is enough, those tiny pads should flow in a second or two upon contact.

https://oscarliang.com/soldering-guide/

(28-Mar-2024, 03:07 AM)mstc Wrote: Don't see anything wrong in your settings, and your wiring seems correct (assuming you have RX to TX and TX to RX). I don't know if the soldering is causing the issue, but I would suggest resoldering in anycase. The exposed wires are too long, they could cross and short out in a crash or if you shrink wrap/twist them. You should trim down the wire ends so there is very little exposed wire extending beyond the solder joint. It is hard to make out from the photo, but also looks like solder was not flowed correctly, it looks patchy (cold solder) instead of a single shiny smooth blob/ball. If your tip is not too small and iron temperature is enough, those tiny pads should flow in a second or two upon contact.

https://oscarliang.com/soldering-guide/

Is there any way to see if the radio is even giving inputs to the receiver because I think that could help diagnose if the problem is with the radio or receiver.

You seemed to have mentioned you use the radio with another drone, so assume your radio is working. You can go into the ExpressLRS lua script on your radio, and if you see the letter C in the upper right corner, it is a confirmation that your radio is properly connected to the receiver. It should be as you already mentioned you get the solid led only when radio is on.

You can also select the channels screen on your radio, that will show you the values your radio is transmitting as you move the sticks/buttons.
https://manual.edgetx.org/bw-radios/main-view

(28-Mar-2024, 04:06 AM)mstc Wrote: You seemed to have mentioned you use the radio with another drone, so assume your radio is working. You can go into the ExpressLRS lua script on your radio, and if you see the letter C in the upper right corner, it is a confirmation that your radio is properly connected to the receiver. It should be as you already mentioned you get the solid led only when radio is on.

You can also select the channels screen on your radio, that will show you the values your radio is transmitting as you move the sticks/buttons.
https://manual.edgetx.org/bw-radios/main-view

Ok so all of that is working, I don't know what the issue could be. Betaflight says the drone is disarmed whenever I connect the usb but I'm pretty sure I should still see stick movement. Any ideas?

Please try the following mate.

• re-solder the RX/TX pads on the FC to another RX/TX pair.  Make sure to update the serial port used by the RX in the configuration in betaflight configurator.
  
• check the length of wires, the photos appear to show some loose wire strands on the yellow wire (FC pad) and white wire (RX pad).
  

Can you flash the RX using Expresslrs configurator and betaflight passthrough?

Sometimes stuff just doesn't work and there is a hardware bug.  It's the most frustrating issue after going through a good problem solving process.

(28-Mar-2024, 04:57 AM)ph2t Wrote: Please try the following mate.

• re-solder the RX/TX pads on the FC to another RX/TX pair.  Make sure to update the serial port used by the RX in the configuration in betaflight configurator.
  
• check the length of wires, the photos appear to show some loose wire strands on the yellow wire (FC pad) and white wire (RX pad).
  

Can you flash the RX using Expresslrs configurator and betaflight passthrough?

Sometimes stuff just doesn't work and there is a hardware bug.  It's the most frustrating issue after going through a good problem solving process.

I will try the resoldering and see if it works. Also for future reference, what does using a different uart do?

For flashing the software, I flashed both to 3.0.1 to keep it consistent (that's what the receiver came as and I didn't want to have more issues) but I had to use wi-fi method because betaflight passthrough had the error: Cannot detect RX, blindly Flashing! Using wifi and inputing the firmware file into the update tab of the online express LRS page did not give an error though and since the light went solid green and the radio shows connected, I assumed it worked (used binding phrase to bind). Maybe there was a problem with the firmware but I am not sure if the error is significant.