How to connect diy voltage divider to d4r2??

Cant get your radio to work? General Hardware issues?
Post Reply
Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

How to connect diy voltage divider to d4r2??

Post by Koarl »

Hello!

I soldered a voltage divider like the one in the picture for a 2s lipo:

Image

Can someone please tell me how it has to be connected to a d4r2? I have read a couple of times that I must not connect minus, some say it's ok. I'm a bit confused now. Should I connect ground only to the rx not to the battery, or connect gnd to the battery and not to the rx? Or is minus to be connected to both?
Where do I plug it into the rx? And what is the right setting on the dht-u?

Thanks

User avatar
MikeB
9x Developer
Posts: 17990
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: How to connect diy voltage divider to d4r2??

Post by MikeB »

This is how I connect a voltage divider:
viewtopic.php?f=95&t=4293&p=60766&hilit ... png#p60766.
C1 removes noise and the 1k0 R3 allows full connectivity while protecting from over current problems.

The reason it is suggested that the GND connection is not made is if your main negative connection between the battery and the ESC is not connected, for some reason, all the power current would flow through the receiver via the sensor GND connection.
Including the 1K0 resistor limits such a current and protects the receiver and wiring.

Mike.
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!
User avatar
jhsa
Posts: 19480
Joined: Tue Dec 27, 2011 5:13 pm
Country: Germany

Re: How to connect diy voltage divider to d4r2??

Post by jhsa »

what about connecting the ground only at the battery side? If ground is broken no current would flow at all?

João
My er9x/Ersky9x/eepskye Video Tutorials
https://www.youtube.com/playlist?list=PL5uJhoD7sAKidZmkhMpYpp_qcuIqJXhb9

Donate to Er9x/Ersky9x:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=YHX43JR3J7XGW
Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

Re: How to connect diy voltage divider to d4r2??

Post by Koarl »

Thanks!
Since I have a different divider like the one Mike mentioned, I would only connect ground to the battery, as jhsa recommends.

Which plug do I use on the D4r2? What setting on the Dht-u has to be used?

Thanks
User avatar
jhsa
Posts: 19480
Joined: Tue Dec 27, 2011 5:13 pm
Country: Germany

Re: How to connect diy voltage divider to d4r2??

Post by jhsa »

I wasn't recommending :D I was asking.. ;) :)

João
My er9x/Ersky9x/eepskye Video Tutorials
https://www.youtube.com/playlist?list=PL5uJhoD7sAKidZmkhMpYpp_qcuIqJXhb9

Donate to Er9x/Ersky9x:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=YHX43JR3J7XGW

Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

Re: How to connect diy voltage divider to d4r2??

Post by Koarl »

Makes me even more confused... [emoji13]
User avatar
jhsa
Posts: 19480
Joined: Tue Dec 27, 2011 5:13 pm
Country: Germany

Re: How to connect diy voltage divider to d4r2??

Post by jhsa »

Do as suggested by Mike.

João
My er9x/Ersky9x/eepskye Video Tutorials
https://www.youtube.com/playlist?list=PL5uJhoD7sAKidZmkhMpYpp_qcuIqJXhb9

Donate to Er9x/Ersky9x:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=YHX43JR3J7XGW
Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

Re: How to connect diy voltage divider to d4r2??

Post by Koarl »

Today i found the time to try it out.
I hooked up everything, connected gnd from the rx sideport to minus of the divider, adin from the sideport to the divider and the divider to battery plus. Battery gnd wasnt connected.
The positive thing first: there was no smoke!
But I only get the readings from a1 which is the voltage that comes from the bec. No readings from a2.

Can somebody please help me find the problem?

Thanks
User avatar
MikeB
9x Developer
Posts: 17990
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: How to connect diy voltage divider to d4r2??

Post by MikeB »

First question is:
Have you set the range of A2 in the telemetry setup menu?

Mike.
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!
Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

Re: How to connect diy voltage divider to d4r2??

Post by Koarl »

Eehh, no. What would be the right setting for a 2s lipo?
User avatar
MikeB
9x Developer
Posts: 17990
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: How to connect diy voltage divider to d4r2??

Post by MikeB »

It depends on the voltage divider, not the lipo.
If you use the 2S input on the diagram you posted, then you are using a 4:1 divider.
The input to the Rx is a maximum of 3.3V, so the input to the divider is a maximum of 4 times this = 13.2V.
So 13.2V is the value you enter for the A2 range.

Mike.
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!
User avatar
jhsa
Posts: 19480
Joined: Tue Dec 27, 2011 5:13 pm
Country: Germany

Re: How to connect diy voltage divider to d4r2??

Post by jhsa »

And confirm the voltage reading is correct with a voltmeter..
My er9x/Ersky9x/eepskye Video Tutorials
https://www.youtube.com/playlist?list=PL5uJhoD7sAKidZmkhMpYpp_qcuIqJXhb9

Donate to Er9x/Ersky9x:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=YHX43JR3J7XGW
User avatar
gohsthb
Posts: 1412
Joined: Wed Dec 28, 2011 2:32 pm
Country: -
Location: Naperville, IL

Re: How to connect diy voltage divider to d4r2??

Post by gohsthb »

To get the ratio Mike posted: (1.5+4.5)/1.5=4

Sent from my LG-D801 using Tapatalk
Koarl
Posts: 203
Joined: Sun Jul 01, 2012 5:08 pm
Country: -

Re: How to connect diy voltage divider to d4r2??

Post by Koarl »

It works, thanks!

Post Reply

Return to “Hardware”