[mod] MinimOSD RSSI > 255 Support

[haydent]

Ok, so following this guide: http://rcexplorer.se/diy/2011/01/lost-packet-indicator/ you can mod your Futaba Fasst Reciever that doesnt have an Rssi Output to have one of sorts via the Red Lost Packet LED.

For this i just used 'standard' sized components not SMD ones.

But what next, as the guide doesnt use MultiWii or MinimOSD.

Well MultiWii reads the chosen Analog Pin (defaults to A3 when enabled in config.h) just fine, its MinimOSD (or more specifically http://code.google.com/p/rush-osd-development/) that doesnt process what its being sent the way it could.

A- It expects a high value to equal strong signal and a low value to indicate weak signal, but with this mod, its the other way around.

B- MinimOSD only allows for a maximum value of 255 yet this rssi mod supplies up to 1.7v which translates to about 347 (arduino analog pin scale 5v 0-1023)

So you need to make some changes in MinimOSD code to override this limit and also change the RSSI calculation formula to work with our mod:


Firstly in GlobalVariables.h near Line 184:

Code: Select all

//haydent
//uint8_t MwRssi=0;
uint16_t MwRssi=0;
//haydent

And Lastly in KV_Team_OSD near Line 421:

Code: Select all

  //haydent
  Settings[S_RSSIMIN] = 8;
  Settings[S_RSSIMAX] = 347; 
  aa =  100 - (((aa-Settings[S_RSSIMIN])/(Settings[S_RSSIMAX]-Settings[S_RSSIMIN])) * 100);
  //aa = ((aa-Settings[S_RSSIMIN]) *101)/(Settings[S_RSSIMAX]-Settings[S_RSSIMIN]) ;
  //haydent

ENJOY !

[haydent]

also depending on the minor differences in your mod and system you may need different values for RSSIMIN & RSSIMAX to give you a scale of 0 - 100 % .

you can either trial and error it, or pass the rssi reading in multiwii code to debug and read it via gui (what i did)

[haydent]

actually alternatively these reading mods could be done in multiwii code before it is sent out to for example MinimOSD ... something to think about

[kataventos]

Hi,
yep it could be included on official release if more people shows interest on it, not many use it but you figured how to get yourself and your gear up and running.

Cheers,
-KV

[haydent]

[edit]

[haydent]

Hi,
yep it could be included on official release if more people shows interest on it, not many use it but you figured how to get yourself and your gear up and running.

Cheers,
-KV

you seem to suggest that your using a similar circuit and getting analog rssi viewtopic.php?f=8&t=3638

so i think it would be small change (i could wright the patch) that makes KV firmware support analog rssi over 255 and also offers inverted calculation (ie high volts = low signal)

how about it ?

[kataventos]

Of course

But I need to understand... I am using Multiwii code for the readings, do you also or are you using Minim mods?

[haydent]

i use multiwii connected sensors, that was my inspiration for making my mods, to avoid hardware mod minim. not that i dont think i could do it, its more that i didnt need to. and having a mega, i have plenty of spare analog pins.

and as mentioned in OP multiwii reads and sends through the serial protocol any rssi value from 0-1023 (arduino voltage reading)