LibrePilot Forum
Development => Hardware => Topic started by: jtrout19 on March 20, 2016, 12:50:12 am
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So i have been reading somethings about getting an rssi value from this reciever with a small mod to it. My question is will this mod work with the revo. I am just wanting a aignal strength displayed on my osd to know when to turn around. I am a little afraid to take the thing further than 100 ft from me. And in all my years i have never done a range test. Maybe thats all i need to do but still. I figured i would ask in case anyone else ever had the question
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the green version in download table should fit your needs:
https://librepilot.atlassian.net/wiki/display/LPDOC/MinOPOSD+setup#MinOPOSDsetup-Downloadsdownloads
Take a look here for filter RSSI signal from your receiver:
https://code.google.com/archive/p/minoposd/wikis/AnalogRSSI.wiki
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Awesome information thank you. The max V I will be able to get from the mod is 500mv and that is soldering to a very small capacitor. If I solder to the larger smd LED I can only get 300mv. Is there a way to mod the code to define max voltage at 500mv or 300mv
So what I'm thinking is that if I want to change the internal voltage reference from 1.1 to 300mv I am going to have to compile my own firmware. I downloaded the repository from bitbucket. Now the question is which files do I compile after I change the reference voltage? OSD is receiving all info from the revo except for RSSI. If I could just edit the .hex file that would be so much easier. Is there a source file for that particular HEX somewhere?
The other possibility is I am looking at this all wrong. Let me know if I am.
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Why do you want to change the vRef ?
Edit: Assuming it can be modified...
(https://forum.librepilot.org/index.php?action=dlattach;topic=1128.0;attach=2116)
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Well the RSSI value on the OSD sits at 4% no matter what. If i switch to RAW value it sits at 10. It say on this page https://code.google.com/archive/p/minoposd/wikis/AnalogRSSI.wiki (https://code.google.com/archive/p/minoposd/wikis/AnalogRSSI.wiki) that internal reference voltage is 1.1v The mod I did to my receiver has a max value of 300mv. Am i not getting something here. The mod uses the green LED on the receiver to provide RSSI
My receiver does not come from the factory with the ability to output RSSI. I have the FrSky V8fr-ii HV. You have to mod it to output RSSI on channel 8. Which I have done.
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...I am going to have to compile my own firmware. I downloaded the repository from bitbucket. Now the question is which files do I compile after I change the reference voltage? OSD is receiving all info from the revo except for RSSI. If I could just edit the .hex file that would be so much easier. Is there a source file for that particular HEX somewhere?
If the source code you downloaded is https://bitbucket.org/f5soh/minoposd and the hex file you're talking about is one from https://librepilot.atlassian.net/wiki/display/LPDOC/MinOPOSD+setup#MinOPOSDsetup-Downloadsdownloads then you have the source for that hex file. The different versions are created by changing #define statements in the code.
You don't actually want to change the reference voltage, that would require hardware changes to provide a different vref voltage to the chip. You probably just want to scale the readings differently and that would just be a change somewhere in the code. I'm not familiar with it so I can't tell you where in the code it is. Load it into the arduino editor and look around.
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Well with that info. I got to playing around with it and turns out all i had to do was change the max RSSI value from 255 to ~98. Those values give me a 100% with the transmitter on and right next to the receiver and 0% when I turn the Transmitter off. Jeez I made that harder than I should of........lol. I have the tendency to do that sometimes.
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A whole 22 minutes, what took you so long? ;D
I'm glad it's working for you now.
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:) ::)
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lol I know right. I guess at least I figured it out. My wife is getting a little annoyed with me. I work on this thing every night. I took it all apart tonight and ran all the wires inside of my arms for a cleaner look. Now to make sure everthying spins the right direction again.