Hi

Here is a tcl/tk program for the calculation of the FrSky voltage sensor (FBVS-01) digits and sensor ratio.
The program selects a best ratio (2:1-6:1) depending on battery type and cells. Also the digits and the alarm voltage
depending on Voltage Alarm per cell is displayed.

Download of the program (.exe):

snoopy-schulz.square7.ch/voltage_divider.exe

Best regards
Micha

# Michael Schulz 21.01.2012

proc calculate {} {
  global Cells Accu Ratio VD VA BV
  
  if {($Accu == "LiPo")} {set ucell 4.2}
  if {($Accu == "LiIo")} {set ucell 4.1}
  if {($Accu == "LiFePo")} {set ucell 3.6}
  if {($Accu == "NiMh")} {set ucell 1.4}
  set U [expr $Cells * $ucell]
  
  if {($Accu == "LiPo") && (($VA < 3.1) || ($VA > 3.6))} {tk_messageBox -icon error -message \
                                        "Is no valid alarm voltage!
                                        \nUse 3.1 Volt - 3.6 Volt."}
                    
  if {($Accu == "LiIo") && (($VA < 2.6) || ($VA > 3.4))} {tk_messageBox -icon error -message \
                                        "Is no valid alarm voltage!
                                         \nUse 2.6 Volt - 3.4 Volt."}      
  
  if {($Accu == "LiFePo") && (($VA < 2.2)|| ($VA > 2.6)) } {tk_messageBox -icon error -message \
                                        "Is no valid alarm voltage!
                                         \nUse 2.2 Volt - 2.6 Volt."}   
                                         
  if {($Accu == "NiMh") && (($VA < 1.0) || ($VA > 1.1))} {tk_messageBox -icon error -message \
                                        "Is no valid alarm voltage!
                                         \nUse 1.0 Volt - 1.1 Volt."}                                                                                                     
  
  
  set RA [expr $U/3.3]
  set Ra 2.0
  if {($RA > 2.0)} {set Ra 4.0}
  if {($RA > 4.0)} {set Ra 6.0}
  
  set Ra [format %1.0f $Ra]
  $Ratio delete 0 100 
  $Ratio insert 0 $Ra
  
  set Vd [expr ($VA*1.0*$Cells/$Ra/3.3)*256.0]
  set Vd [format %1.0f $Vd]
  $VD delete 0 100 
  $VD insert 0 $Vd
  
  set Bv [expr $VA*1.0*$Cells]
  set Bv [format %1.1f $Bv]
  $BV delete 0 100 
  $BV insert 0 $Bv
  
  
  if {$RA >= 6.37} {tk_messageBox -icon error -message \
                    "Not valid max voltage!
                    \nUse DIY voltage divider."}
                                      
}

proc gui {} {
      global Cells Accu Ratio VA VD BV
      wm minsize . 270 300
      wm title . "FrSky Voltage Divider V1.0"
           
      set a [labelframe .a -bd 3]
        
        set m2 [frame .a.m2]
        set f2 [frame $m2.f2]
          set lf2 [label $f2.lf2 -text "Accu Type: " -font {Arial 10 bold }]
          tk_optionMenu $f2.1 Accu LiPo LiIo LiFePo NiMh
          pack $lf2 -side left
          pack $f2.1 -side right
        pack $f2 
       pack $m2 -fill x -pady 6  
        
        set m [frame .a.m]
        set f1 [frame $m.f1]
          set lf1 [label $f1.lf1 -text "Cells: " -font {Arial 10 bold}]
          tk_optionMenu $f1.1 Cells 1 2 3 4 5
          pack $lf1 -side left
          pack $f1.1 -side right
        pack $f1 
       pack $m -fill x -pady 6
        
        set a5 [frame $a.a5]
          set al [label $a5.l -text {Voltage Alarm per Cell [V]} -font {Arial 10 bold }] 
          set ae5 [entry $a5.e -width 3 -justify right -textvariable VA -font {Arial 10 }]
          pack $al -side left
          pack $ae5 -side right
        pack $a5 -fill x -pady 6 
       
      pack $a -fill y -pady 10
   
      set b [labelframe .b -bd 3]
        set b1 [frame $b.b1] 
          set bl [label $b1.l -text {Ratio } -font {Arial 10 bold }] 
          set Ratio [entry $b1.e -width 4 -justify right -font {Arial 10 }]
          pack $bl -side left
          pack $Ratio -side right
        pack $b1  -fill x -pady 6
        
        set b2 [frame $b.b2] 
          set bl [label $b2.l -text {Value Digits } -font {Arial 10 bold}] 
          set VD [entry $b2.e -width 4 -justify right -font {Arial 10 }]
          pack $bl -side left
          pack $VD -side right
        pack $b2  -fill x -pady 6
        
        set b5 [frame $b.b5] 
          set bl [label $b5.l -text {Alarm Voltage } -font {Arial 10 bold}] 
          set BV [entry $b5.e -width 4 -justify right -font {Arial 10}]
          pack $bl -side left
          pack $BV -side right
        pack $b5  -fill x -pady 6
                     
      pack $b -fill y -pady 10    
    
      set bu [labelframe .bu] 
        button $bu.1 -text "Calc" -command {calculate} -font {Arial 10 bold } -bd 3
        pack $bu.1 
      pack $bu
       
}      

########################## Main ###############################################  
set ignore [catch {eval {wm iconbitmap . -default [file join \snoopy.ico]}}]
global VA Cells
set VA 3.4; set Cells 3
gui

Hi builder,
From what I have researched and the information on FliteTest, the most effective way to orientate your 2.4 antenna is with the joint at a "L" shape or bent. Your antenna on the transmitter has a "dead" spot in the middle and If you point the transmitter directly at your receiver "or plane in this case", you could lose signal for a moment. While keeping it bent, your spread will be much more effective.

Hope that's what your looking for.

Regards
Brian

Originally Posted by u2builder

As someone who is relatively new to 2.4, I have been wondering about the proper position for the antenna. With my 72 system of course the antenna comes straight out of the top of the radio, and based on the way I hold the radio I'd say maybe it is somewhere between horizontal and 30 degrees up from horizontal.

The 2.4 Frsky radio has a "joint" in it that allows it to be more vertical. When I was doing my "range testing" it did seem that a more vertical orientation gave me more range. What gave me a huge amount of additional range in range checking was holding the transmitter at head level.

Anyway, what is the optimum orientation of the antenna with respect to the ground. Does it vary with how high you fly? Does it matter?

Hi builder,
From what I have researched and the information on FliteTest, the most effective way to orientate your 2.4 antenna is with the joint at a "L" shape or bent. Your antenna on the transmitter has a "dead" spot in the middle and If you point the transmitter directly at your receiver "or plane in this case", you could lose signal for a moment. While keeping it bent, your spread will be much more effective.

Thank you. This does confirm the experience I have had in my range test and it makes sense that they would not put the joint in the if it wasn't needed.

Originally Posted by u2builder

Thank you. This does confirm the experience I have had in my range test and it makes sense that they would not put the joint in the if it wasn't needed.

It's really simple: Don't point the antenna directly at the model. That's all.

In practice, radios are good enough that they tolerate almost anything nearly all the time. But to reduce the chances of signal loss, it's advisable not to point.

Everybody agrees on that. The real arguments come when people try to decide on the best antenna orientation to avoid pointing! I'm of the "bend it over to one side" school and have never had a problem. On the other hand, I have a DX4e, and its antenna doesn't bend at all, but it works perfectly.

One reason for bending to one side is that you can leave it there permanently and it will fit into most cases without having to bend a different way. This minimizes the strain on the fairly vulnerable coax.

Yes, raising the TX above your head will increase range. The only time I've had to do this was when flying a Parkzone Champ with the low power Tx that comes with it. We had put the model on floats and it performed perfectly in the air. But when it landed 100m or so away, I had to raise the TX over my head to taxi back.

Originally Posted by u2builder

Anyway, what is the optimum orientation of the antenna with respect to the ground. Does it vary with how high you fly? Does it matter?

And to answer this question,

If you were flying above 1.5km yes it would matter. Max effective range on a stock Frysky is near 1.5km. Far to high for you to be without an FPV platform. Now if your talking patch antennas, you can reach out to as far as 3-5km as long as you keep the patch pointed at the aircraft. This again is what I have only researched.

I'm new to FPV, therefore haven't yet explored the maximum range with my Frysky system. I'm getting there slowly though

"stick" antennas radiate (throw their signal) out the sides, and not much straight out the end.
higher gain (larger dBi or dBd rating) throw the signal out at a narrower angle.. and even less out the end.

the best results are with the antennas parrallel, not always possible with aircraft..

Helix (spiral) antennas radiate out the sides for antennas with two turns or less, over 2 turns they radiate out the end.

I used to make antennas....



apologies for the crude drawing, havent had my morning cup of coffee yet...

Thanks. "A picture is as good as 1000 words". I learned quite from the last few posts.

I''ve just bought another v8fr-ii to use with my dht diy telemetry module.
I've followed the instructions to bind the receiver with my telemetry-enabled module by inserting a jumper across the data pins of chan 1&2. I use a 6v battery to directly power the receiver.
Power on transmitter in bind mode, power on receiver. Receiver red light stays solid. Remove power, remove jumper, power trans, receiver. The receiver's red light flashes indicating no signal.
I think i have a faulty receiver.
Any thoughts??

Is the TX module really in D mode? Check the little switches.

Originally Posted by TheCure

I''ve just bought another v8fr-ii to use with my dht diy telemetry module.
I've followed the instructions to bind the receiver with my telemetry-enabled module by inserting a jumper across the data pins of chan 1&2. I use a 6v battery to directly power the receiver.
Power on transmitter in bind mode, power on receiver. Receiver red light stays solid. Remove power, remove jumper, power trans, receiver. The receiver's red light flashes indicating no signal.
I think i have a faulty receiver.
Any thoughts??

Are you pushing and holding the bind button on the receiver when you power it up after powering the TX in bind mode? Let bind button off before powering everything down?

EDIT --- wait I was thinking of V8R4-II -- -I'm not familiar with v9fr-ii

EDIT #2 --- back to original thought -- you are holding the F/S button on the receiver before you apply power and holding it until receiver LED is flashing. Then let up the button... and power off receiver .. power off TX...... power on TX normally ... .power on RX normally... light should NOW be solid indicating you have a link.

Ansering the two posts above:

No, I am not binding in v8 mode on Tx. The switch is in middle position within my transmitter. I also tried with another frsky dht-equipped transmitter and get the same effect.

No, I didnt use the F/S button since the manual says not to when using the jumper configuration when binding in D mode:

"D_Mode (Telemetry)
Connect Ch1 & Ch2 signal pins of V8FR-II by provided jumper and then
connect battery to V8FR-II directly (no need to hold the F/S button on V8FR-II) "

This is the receiver in question:
http://www.frsky-rc.com/ShowProducts.asp?id=124

Originally Posted by TheCure

Ansering the two posts above:

No, I am not binding in v8 mode on Tx. The switch is in middle position within my transmitter. I also tried with another frsky dht-equipped transmitter and get the same effect.

No, I didnt use the F/S button since the manual says not to when using the jumper configuration when binding in D mode:

"D_Mode (Telemetry)
Connect Ch1 & Ch2 signal pins of V8FR-II by provided jumper and then
connect battery to V8FR-II directly (no need to hold the F/S button on V8FR-II) "

This is the receiver in question:
http://www.frsky-rc.com/ShowProducts.asp?id=124

At this point you seem to have your bases covered. But I've included a photo of the DHT to assure this is what you mean. (a picture is worth 1000 words). If you have these two switches off and do the jumper correctly and are not binding -- then I'd say you do have receiver problems.

can you bind it in V8 mode? (just to test..)

Originally Posted by rcroadtrain

can you bind it in V8 mode? (just to test..)

Thats a logical question. Unfortunately i dont want to open any of my transmitters to get at the switch.
I have another of the same receiver model, and it binded fine using the same technique, i just thought maybe there is a new firmware revision that isnt compatible with my older dht.
Dont think thats the case though.
I've opened a ticket with hobbyking. I had to go through the whole video proof thing.
Wish me luck.

At least they won't make you send it back. Better to have to send a video than pay postage .

We had Someone with a similar issue at my club. Will have to ask if he worked it out.