<p>I am working with a Pixhawk 4 and a Spektrum AR620 receiver. The receiver has a 3x7 grid of pins labelled (-, +, S), and (Batt, 1-6). The reciever says it is a DSM2/DSMX receiver, and I want to connect it to the DSM port of my flight controller. However I am unsure what connections are supposed to be made. Where do I attach the DSM connector wire to the receiver? I tried attaching the dsm header to channel one of the reciever, but then QGroundControl (my mission planner) couldn't read anything from it. The receiver is bound to the transmitter (spektrum DX6i), even while connected to the pixhawk. It is definately reciever signals too (as measured by a voltmeter applied to the signal wire and checking the voltage changed with respect to transmitter movements.) However this was done before hand, and then I plugged it into the pixhawk. The spektrum bind button gives an error &quot;vehicle did not respond to command: MAV_CMD_START_RX_PAIR&quot;, no matter what mode I attempt to start it in (I realize this isn't necessary because it is already bound, but I am trying everything). Most of the pixhawk settings are still default, except I set SYS_USE_IO to 0 so that I could use my main motors in the FMU out. The ACT light of both IO and FMU are constantly flashing blue. I am using a basic quad frame. I have tried many steps including holding switch, reflashing firmware, etc. I still recieve the same error, &quot;0 channels detected. To operate pixhawk you need at least 5 channels&quot;</p>
<p>Edit-- Pictures of Reciever and FC connections
<img src="https://i.sstatic.net/RNIFj.jpg" alt="enter image description here" /><img src="https://i.sstatic.net/RqboK.jpg" alt="enter image description here" /></p>

CC BY-SA 4.0
2021-04-01T23:01:02.080Z
Could you describe how you tried physically hooked the RX to the FC? i.e. which pins were connected where? Also, did you remember to configure the PixHawk to communicate with the RX using DSM2/DSMX?
ifconfig
CC BY-SA 4.0
2021-04-02T19:57:44.520Z
left to right on pixhawk. 2nd pin on dsm connected to signal of port 1 on reciever, 4th pin to + on reciever, and 5th pin to - on reciever. And how do you configure pixhawk to use DSM? Are there special parameters that need to be changed? Thanks
figbar
CC BY-SA 4.0
2021-04-02T23:31:22.287Z
Could you edit your post with a photo of the connection? Also, have you made sure that the receiver has power? (*It appears I was mistaken and the only configuration required on the PX4 is to connect the RX to the DSM port, no software required*)
ifconfig
CC BY-SA 4.0
2021-04-03T17:33:22.680Z
Edited. And yes, the reciever has power when the fc is powered
figbar
CC BY-SA 4.0
2021-04-04T05:56:55.847Z
Hrm, this really stumps me! I'm not sure I can help anymore without being there in person to reason things out. :( I've tried looking through the PX4 docs (https://docs.px4.io/master/en/assembly/quick_start_pixhawk4.html) for info on possible software setup and the PX4 pinouts (http://www.holybro.com/manual/Pixhawk4-Pinouts.pdf) to see if there is any wiring mismatch, but I can't find anything that appears contradictory to your pictures. Sorry, man! I hope you can figure this out somehow.
ifconfig
CC BY-SA 4.0
2021-04-04T07:13:21.697Z
ok, thanks for trying
figbar
CC BY-SA 4.0
2021-04-04T21:30:47.963Z
Looking at this (http://www.holybro.com/manual/Pixhawk4-Pinouts.pdf), you could try pin 1 (5V) on the PixHawk for power to the RX? Depending on tolarances the 3.5V might actually be slightly too low for the AR620, which a search suggests accepts 3.5-9V?
Kralc
CC BY-SA 4.0
2021-04-05T21:15:40.503Z
no, unfortunately that did not help, it appears to yield identical behavior.
figbar
CC BY-SA 4.0
2021-04-06T08:25:26.650Z
I noticed that on the current AR620, channel 1 is labelled as 1/Data, while on yours it's not. https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMAR620 That may mean that it is an old one that doesn't support a data connection. I can't see anything in the (current) manual about switching between PWM and DSM modes. I suggest you try Horizon support, they're normally quite helpful.
Robin Bennett
CC BY-SA 4.0
2021-04-07T21:52:35.773Z
Thanks for the suggestion, but I emailed them and they told me that it is just an alternate case design, and that the function remains the same
figbar
<flight-controller><receiver><spektrum>
DSM from Spektrum Reciever
figbar
# DSM from Spektrum Reciever

(Asked by: username_0 on 2021-04-01)

I am working with a Pixhawk 4 and a Spektrum AR620 receiver. The receiver has a 3x7 grid of pins labelled (-, +, S), and (Batt, 1-6). The reciever says it is a DSM2/DSMX receiver, and I want to connect it to the DSM port of my flight controller. However I am unsure what connections are supposed to be made. Where do I attach the DSM connector wire to the receiver? I tried attaching the dsm header to channel one of the reciever, but then QGroundControl (my mission planner) couldn't read anything from it. The receiver is bound to the transmitter (spektrum DX6i), even while connected to the pixhawk. It is definately reciever signals too (as measured by a voltmeter applied to the signal wire and checking the voltage changed with respect to transmitter movements.) However this was done before hand, and then I plugged it into the pixhawk. The spektrum bind button gives an error "vehicle did not respond to command: MAV\_CMD\_START\_RX\_PAIR", no matter what mode I attempt to start it in (I realize this isn't necessary because it is already bound, but I am trying everything). Most of the pixhawk settings are still default, except I set SYS\_USE\_IO to 0 so that I could use my main motors in the FMU out. The ACT light of both IO and FMU are constantly flashing blue. I am using a basic quad frame. I have tried many steps including holding switch, reflashing firmware, etc. I still recieve the same error, "0 channels detected. To operate pixhawk you need at least 5 channels"

Edit-- Pictures of Reciever and FC connections
![enter image description here](https://i.sstatic.net/RNIFj.jpg)![enter image description here](https://i.sstatic.net/RqboK.jpg)

**Tags:** flight-controller, receiver, spektrum

> **Comments:**
> **username_1**: Could you describe how you tried physically hooked the RX to the FC? i.e. which pins were connected where? Also, did you remember to configure the PixHawk to communicate with the RX using DSM2/DSMX?  
> **username_0**: left to right on pixhawk. 2nd pin on dsm connected to signal of port 1 on reciever, 4th pin to + on reciever, and 5th pin to - on reciever. And how do you configure pixhawk to use DSM? Are there special parameters that need to be changed? Thanks  
> **username_1**: Could you edit your post with a photo of the connection? Also, have you made sure that the receiver has power? (*It appears I was mistaken and the only configuration required on the PX4 is to connect the RX to the DSM port, no software required*)  
> **username_0**: Edited. And yes, the reciever has power when the fc is powered  
> **username_1**: Hrm, this really stumps me! I'm not sure I can help anymore without being there in person to reason things out. :( I've tried looking through the PX4 docs (https://docs.px4.io/master/en/assembly/quick_start_pixhawk4.html) for info on possible software setup and the PX4 pinouts (http://www.holybro.com/manual/Pixhawk4-Pinouts.pdf) to see if there is any wiring mismatch, but I can't find anything that appears contradictory to your pictures. Sorry, man! I hope you can figure this out somehow.  
> **username_0**: ok, thanks for trying  
> **username_2**: Looking at this (http://www.holybro.com/manual/Pixhawk4-Pinouts.pdf), you could try pin 1 (5V) on the PixHawk for power to the RX? Depending on tolarances the 3.5V might actually be slightly too low for the AR620, which a search suggests accepts 3.5-9V?  
> **username_0**: no, unfortunately that did not help, it appears to yield identical behavior.  
> **username_3**: I noticed that on the current AR620, channel 1 is labelled as 1/Data, while on yours it's not. https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMAR620 That may mean that it is an old one that doesn't support a data connection. I can't see anything in the (current) manual about switching between PWM and DSM modes. I suggest you try Horizon support, they're normally quite helpful.  
> **username_0**: Thanks for the suggestion, but I emailed them and they told me that it is just an alternate case design, and that the function remains the same  

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## 0 answers

