Telemetry voltage alarm adj for 3S & 4S with gear switch

[Ozzy]

When I fly quads with my openTx 9x, I use 3S and 4S packs. With FrSky telemetry, resetting the low voltage alarm values for the 3S and 4S packs every time is not fun. I could use 2 models but I am already low on memory with 13 models in use. Could I use my gear switch to select between the 3S and 4S alarm parameters, or any other suggestion?

I am totally open to replacing the Atmega64 with the 2561, just was not sure if it will be supported (now and in the future). Thanks in advance!

[Kilrah]

You could forget about the "stock" frsky telemetry, and use the custom switch / custom function approach instead.

[jhsa]

if the voltage divider/sensor you're using is able to read 4S you can use something like this..

CS1 a<x A2 12.7V (Detects 3s lipo)
CS2 a<x A2 10.2V AND CS1 (this is your 3S alarm)

CS3 a>x A2 12.7V (This detects the 4S Lipo)
CS4 a<x A2 12.8V AND CS3 (This will trigger the low Batt alarm for the 4S battery

Custom functions
CS1 play track < Your voice alarm file number> (if you have voice),or Play sound <choose sound>
CS2 (the same as above, choose the sound or voice file to play)

I didn't test this. just thought of it now.. the only thing is that you can't set the alarm for the 4S too low or the radio will think that zou have a 3S.. but I think that if you set the alarm at 3.2V per cell which is if I'm not mistaken 12.8V, you should be ok..

If this is wrong, please someone correct me, or maybe there is a better way of doing it..

João

[Kilrah]

I wouldn't use an "automatic detection", that won't work as the voltage ranges overlap. As soon as the 4s pack goes below 12.7V your CS would go to "3s mode", and the alarm would stop sounding although it's when it would start being required. Actually your solution would beep for 4s only when the voltage is between 12.7V and 12.8V, not included = pretty much never.
But just AND the 3s threshold with a switch position, and AND the 4s threshold with the other switch position.

[jhsa]

That's why I said that he can't have the 4S alarm too low..

EDIT: maybe Kilrah is right.. you would have to set the threshold for the 4S alarms a bit higher and then probably not use the complete charge of your battery.. and I misunderstand your post obviously. Yiou said you would like to use a switch but I'm in automatic mode today
maybe the following is more appropriate

CS1 a<x A2 <your 3S alarm voltage> AND !GEA
CS2 a<x A2 <your 4S alarm voltage> AND GEA

Custom functions as in my post above..

Kilrah, are you happy now eh??
João

[Flaps 30]

I think JHSA has it right. Personally I feel that it isn't a good idea, as one day you will forget to flick the switch to the right position... 4S selected instead of 3S as fitted.. Not good.

I am totally open to replacing the Atmega64 with the 2561, just was not sure if it will be supported (now and in the future). Thanks in advance!

I have no idea if the 2561 will go anywhere.. You could replace the M64 with the M128 and with that get double the model memory space, so you can have one model set for 3S and the other for 4S. Going that route would also mean that you could buy yet more models to fill up the blank slots.

[jhsa]

The 2561 gives us more RAM.. oh, and guess what...

No, not yet, but quoting a forum member " I'm warming up my soldering iron"

[Ozzy]

The 2561 gives us more RAM.. oh, and guess what...

No, not yet, but quoting a forum member " I'm warming up my soldering iron"

Hot air will change that chip in 1 minute

[jhsa]

well, I don't own a hot air station. My wife's hair dryer might not be up to the job and my hot air gun might be a bit too hot, so I think I'll go with chip quik again.. 20 minutes and job done.. with some luck

[Ozzy]

I learned soldering BGA (ball grid array) and CSP (chip scale package, basically there is no package, no lead frame and plastic to make the part larger) a few months ago. I now can hand solder 0.4mm pitch BGA and CSP packages. In this picture I have soldered force and sense wires to several ball pads for trouble shooting. Wire used is 0.6mm (0.0025") diam. Chip size is 2.5mm X 3.0mm with 0.4mm ball spacing on a 42 ball package, you can see the standard 0.1" hole spacing bread board under the Kapton tape for reference to the small size of this IC. I can also remove and replace this part in 1 minute by hand with hot air station, it's really cool to see the solder re-flow and the part auto align under the micro scope, someday I would like to video the process, but would be difficult, I also switched to a different flux for these packages, it's called Tacky-Flux

My rework station looks like this
http://www.ebay.com/itm/NEW-852D-2in1-S ... 4ac33b49ce

[Flaps 30]

Go grab yourself an M128... That will be nothing to what you can do with the small stuff.

[jhsa]

or even better wait for the tests with the atmega 2561

[afon]

Did somebody find a solution for 3S and 4S alarms without physical switch (so openTx knows whar LiPo was used)?