Connecting a lost model alarm / voltage alarm on Femto F3 F.C. - FT Gremlin

[NiCK_NaMe]

I would like to connect a alarm to my Gremlin. But I just fried my flight Controller trying to do it. I followed the instructions provided with the alarm. Didn't work or I would be a happy flier right now. If someone wants to help me tackle this problem who has more experience with flight controllers and the wiring involved I would HIGHLY appreciate this.

Reason why I want to do this... I lost my first gremlin in a farmers field with grass that is higher than my knees... and it rained the next day. So it is inevitably GONE.

I would like to connect this 3 in 1 lost / voltage alarm into the Femto F3 Flight Controller:


Here is this wiring scheme for this alarm:


Here are the directions for the wiring scheme:

Battery monitor function (F1)
Hold the button 3 seconds to enter the setting of the voltage threshold.
Press button to set the alarm threshold between 3.4 ~ 3.7V / Cell (red LED).
The value will be saved & exit if no action within 10 seconds.

2. Discovery buzzer function (F2)
It is easy to use the function, just plug it in one Aux channel (e.g. Gear). Move the toggle switch to one side or another side, the BM3in1 will alarm "BeepBeepBeepBeepBeep" & blue LED blink.

3. Signal loss alarm function (F3)
It can warn you if you turn off the transmitter first by mistake, if you have trouble finding a model in the long grass...

-----------------------------------------------


You can use combinations, For me I would like to use combination of F1+F3
So I have a voltage alarm to protect my battery, and a alarm for if my quad looses signal.

If anyone want to take shot at this or explain to me what I need to do please I would appreciate the help. I followed th F1+F3 diagram on 2 Femto FC now and fried them both. You can rule out that I created a bridge of any kind, That's why I did the second Femto FC. to rule out the possibility. I took my time and wasted 4 hours soldering the 2nd FC to make sure it was done perfectly... Used a multi-meter no "BEEEEEEP!!!" so I said alright here i go, Pluged in a batter and "poof" magic smoke.

 

[French]

Unfortunately, I think you tried to make this a bit more difficult than it actually is. The femto has built in pads for a small 5V buzzer (solder tiny wires to the pads then to the buzzer).

 

[TazRC]

To add to French's response: https://youtu.be/wAvTvkBuPIc?t=10m

 

[NiCK_NaMe]

French, TazRC.

Wow I burnt up two Fem F3's and it turns out to be this easy of a solution...


Thanks for the help, I ordered another FC from Flitetest, let's hope it will come quickly!

 

[NiCK_NaMe]

So here is the plan. Using the beeper / voltage alarm I have. I will follow the F1+F2 diagram. Leaving the white signal wire off and soldering to the buzzer pads. And connecting the battery leads to the battery as pictured. Does anyone see a problem I may have with this configuration? Believe it will or will not work?

I will update with a picture when I get the FC in the mail.

Again thanks for the help!

 

[TazRC]

I personally haven't used one of those voltage alarms so without seeing a schematic it's hard for me to tell. There's probably a relay or solid-state switching device that fires the buzzers and that may complicate things, unless you know two pads go directly to the buzzer(s). If it were me, I would just desolder one or both of the buzzers, or just buy the recommended voltage buzzer, and attach to short lengths of wire and glue it to something. Perhaps someone that has used this particular voltage alarm can chime in with more info for you.

 

[French]

Just a thought, why not desolder one of the buzzers from the alarm you have and wire it directly to the femto buzzer pads (confirm polarity)? Since this is going on a gremlin, that would minimize weight and size.

My guess is the bigger pads are the ground.

 

[NiCK_NaMe]

That is one idea. Sounds like a good one. A thought on confirming polarity I could get one of my 3v batteries from my alarm clock. And try and do that...

I run a voltage checker on my gremlin already... this one:

I know it adds a bit of weight but I like to land as close to 3.7v as I can. Setting it to 3.6v usually does the trick after the "slag" runs off the battery is usually around 3.7v. The original voltage alarm weights 10g. This alarm and voltage alarm weights 7g with all the wires before cutting them off. For me I don't mind the extra weight for piece of mind and to save battery life and most importantly warn me when battery is getting low before the quad falls from the sky unexpectedly overy the farmer's field of Gremlin eating death grass.

I seen this alarm also doubles as a voltage checker and big bonus is that in all it servers 2 purposes, and weights less that the original voltage alarm I ran on my lost "R.I.P." Gremlin

I think I will give it a try to connect the entire thing. Maybe some one with much knowledge in these tiny electro trinkets, gidgets and do-dads will let me know if I am about to defibrillate the heart of another gremlin

If it all works I will certainly post some photos and details how I did it in case anyone else wants to replicate it!

 

[NiCK_NaMe]

I sure hope that package from Flite Test come quick... I don't know how more of this:
I can handle!

 

[makattack]

Welcome NiCK_NaMe!

Yikes, that lost model alarm / beeper, seems to be designed for fixed wing applications where a flight controller isn't involved. I would also concur with others who suggest simply soldering a buzzer to the buzzer pads of your flight controller vs trying to get that device to work. A buzzer like these https://www.amazon.com/a12081600ux0...8&qid=1496954304&sr=8-5&keywords=piezo+buzzer (you can probably find a cheaper source ... 5 for $12-13 is a bit pricey. I think I got 10 for $10 on ebay but shipping took longer)

The wiring diagram you posted for that lost model alarm looks confusing to me. I'm not sure what "B" and "C" are but if I am correct in assuming "B" is another battery and "C" is a BEC/5V regulator, it's just too much extra stuff not needed in a multirotor application, especially for the little guys.

 

[NiCK_NaMe]

Makattack. Thanks for the advice. Yeah it is used for the bigger fixed wings.

I just can't help but to experiment and try to get things to do what they are not designed for. My wife says that it is a disease I picked up from some where? And that she is tired of me breaking everything? I am digressing right?


Look at this diagram:


French and TazRC have made me change my mind instead of using F1+F3 connection type for voltage and signal loss alarm. After seeing the babyhawk video and French educating me about the buzzer pads on the back side of the FC.

F1+F3 means you need to connect through signal and the ESC along with the Lipo...
F1+F2 connection leads through the lipo and signal. The alarm is rate for 2S-6S Femto FC is also rate from 2S-6S but what I do not know is if the femto buzzer pads as pointed out by French:

Will accept the current that the 3 in 1 alarm feeds it... if anyone know the max volts the femto FC will take to the buzzer pads that you be great. As we can just "assume" that the 3 in 1 will provide the full draw of the 2S battery.

Anyone have detailed info on the Femto F3 Flight Controller? Specifically the volt ratings for the pads?

 

[NiCK_NaMe]

Makattack! BTW, thanks for the link to the 5V buzzer... if this doesn't work out I will definitely be ordering some!

 

[ElectriSean]

The buzzer pads on the FC do not take voltage, if you put voltage to them you will fry something. Those pads put out 5V and a very small amount of current, just enough to run a simple piezo buzzer.

Note that the buzzer pads also give a low voltage warning if you enable vbat monitoring in betaflight, so no need for your lipo checker adding weight as well.

 

[NiCK_NaMe]

ElectriSean!

Boom! You're the man! Problem soved! And you saved me alot of weight! ::Thumbsup!::

 

[NiCK_NaMe]

Makattack, buying your buzzers! Thanks buddy!

 

[TazRC]

Might not need anything. I just read about a BLHeli_S feature that Betaflight now supports where it uses the ESCs and motors as a Beacon alert, similar to typical startup tones but louder chirps. I'm going to look into this for the Babyhawk that I'm working on now.

 

[ElectriSean]

Might not need anything. I just read about a BLHeli_S feature that Betaflight now supports where it uses the ESCs and motors as a Beacon alert, similar to typical startup tones but louder chirps. I'm going to look into this for the Babyhawk that I'm working on now.

This does work, though it's set on a delay - default is 10 minutes - and isn't terribly loud. It also does nothing as a battery warning. Definitely better than nothing though.

 

[TazRC]

This does work, though it's set on a delay - default is 10 minutes - and isn't terribly loud. It also does nothing as a battery warning. Definitely better than nothing though.

I read on GitHub that the newest rev (changed from typical beep to chirp) is louder than most buzzers and the delay can be set to whatever you want, with most guys setting it on 2 minutes. This is great for these smaller quads where additional weight is a deficit. But I'll find out for myself soon enough.

 

[French]

Everyone should be on blheli_s 16.65 for the imperial march startup tone alone!!!

https://github.com/cleanflight/blheli-multishot/releases

 

[NiCK_NaMe]

Now this is definitely something I am going to figure out! That would not require any think additional. Saving weight and money!