Am I being a bit thick? - RM ELRS PWM 4CH RX Questions

Racing Quads, Self-builds & FPV
1

Probably…

4CH ELRS PWN RX… The 5, 6’s, 8’s, etc (I have a 6 I think on the Riot) have an extra input for the power input…

But on this one, there are just 4 channels, and one V+ for “MEASURING” the BATT voltage…

So the question is… Where do I add the 5V, does it have a regulator?

Manual here: https://cdn.shopify.com/s/files/1/0609/8324/7079/files/ER4_Receiver_User_Manual.pdf?v=1687324669

This is interesting on the product page

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A Y cable?

I will only be using 3 outputs, so I guess I use the 4th as a 5V in/gnd from a BEC. No FC on this, two wings, and a motor.

The additional Ext V is for telemetry so I can have the radio shout at me if getting low power, so that’s just a live input from that. I will have to use a BEC (which I got plenty), as the ESC’s I have don’t have a BEC on them.

So yeah maybe just use the 5V input on one of the 4 channels. If I was to use all 4 I guess then you’d have to inject it in on one of the 5V pins on the… Oh that’s why they say use a Y Cable…

Thank you rubber duckies :slight_smile:

2

There’s just 4 servo cables going into that.

Each one has signal, ground and +V.

The grounds and +V are all tied together.

This is the same as your servo tester, you have one, right?

The 5V is passed in from your ESC… which should have a 5V out on a servo cable… this is what non-quad ESCs are like. This is then passed out to the servos, because of the common connection.

Then the battery is directly connected to the VBAT sensor… as you mentioned.

Basically it’s just like your servo tester…

3

It’s a quad ESC with no BEC, so no 5V. (GND and Signal only)

That doesn’t power this.

I’m pretty sure worked it out, just add 5V to the spare channel I’m not using, just 5V/GND from a 5V BEC.

4

So you’ll need to add your own BEC

5

And no it’s not just like my servo tester…

That has a BEC in it (must do), connect a 6S battery to the tester, then connect the servo to the output (Toolit RC M8 FYI)

6

Ah… that’s a charger with servo testing built in…

This is a “proper” servo tester!!

https://amzn.eu/d/1hgym7U

7

Or “old fashioned…” haha

Though this photo shows the “injection” on the two inputs yeah. So In my instance just getting a 5V BEC to power the spare 4th PWM output on the RX will be fine. The Ext BAT connection is just for monitoring, not powering i’m 99% sure

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8

Just saving this for use at a future point in time.

Screenshot 2024-02-20 at 13.52.38

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I remember back in the day when we only had NiCad batteries, brushed motors and analog FM RC systems… (hang on I’ve still got one of those…)

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Hey… I’m ALWAYS right, except when I’m wrong. :wink:

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I think the answer is… yes he was right in that he was being a bit thick…

1 Like
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Well I answered my own question (I think, proof will be on Thursday!) as part of the OP, didn’t want to delete just in case someone else had a similar question.