I’ll probably do this for the 7" as I already have that on digital
What is the weight of a 5" MOD-L frame ? On their web site they do not publish weight data
In the meantime I ordered on cncdrones the ulatr light AOS 5" frame at 55 grams (all hardware included) which can carry two 20x20 stacks (compatible to carry a caddx vista). I will try a light build on that frame.
Do you know a link to these frames ? I checked 5" TBS frames but they are super heavy at 145 grams
Hyper Light, SniperX, they are on the website.
The hyperlite is 108grams, way too heavy (versus the available 55g which is so far the reference of the lightest 5" frame that can carry two 20x20 stacks compatible thus for a caddxvista)
The sniper X is 61grams and can only carry one 20x20 stack (thus not be able to carry a caddx vista)
So it seems the AOS UL5 at 55grams, hardware included is the lightest choice available on the market for a 5" frame than can carry a HD solution
The weight is not declared, but in the comments I read this which could be a good compromise:
mod-L SB 4" frame should be 30g.
Thx. And what about their 5" frame ?
the weight of the frame (carbon only) are 25g (3"), 27g (4"), 30g (4" heavy), 37g (5"), 45g (5" heavy).
I found this info in this link.
If the aim is to create a 250gr sub quadcopter with arducopter, you need to create a quad that is capable of flying at least 10 minutes otherwise you cannot use the advanced features of ardupilot and just use betaflight very easy to set up. To have sub 250 and flight time> 10 min we are obliged to use 100gr 2s Li Ion Vtc6. With this battery I would not go beyond 4 "because otherwise the 2s Li Ion may no longer be sufficient.
However if the aim is to stay below 250gr maybe it is better to use my thread, so we don’t dirty Andy’s thread 
A question for using a Vifly buzzer on the H7 mini : does the buzz+/buzz- pads on this flight controller board work with arducopter’s firmware ? (I see a buzzer defined in the correpsonding hwdef.dat file)
Secondary question : for a passive buzzer to work (with PWM) a timing definition must exist in the hwdef file. I do not see it in the current (latest) H7 mini firmware. Andy, can you add it int he hwdef file ?
Thank you
Hugues
The timer is used by the bdshot outputs so cannot be used on the buzzer.
You can use an active buzzer on the pins but its only on/off.
You can use the 4.2 feature to use a motor output for a buzzer instead.
Thanks. The motor output option seems the best choice indeed for this board. However I do not see to what servo function the corresponding motor/servo output should be set to for that. Do you know ?
Last two (only on 4.2)
Note though that technically you should use a buzzer that is not going to draw a lot of current - e.g. 3-pin buzzer
I tried 138 and 139 on M8 of the Kakute H7 mini board. The buzzer is a Vifly mini with 3 pins : 5V, GND and PWM. I soldered the PWM wire on M8 (servo 8 output configured as 138 or 139).
Results:
-with 138, permanent buzzer sound as soon as battery is connected
-inverting with 139, I get some unrecognizable sounds after plugging the battery. Then stops. The board, via the ESCs (Dshot) emits the normal arducopter startup sounds.
Very frustrating we can’t get a stupid buzzer to work as intended.
I also tried connecting on the buz+/buz- pads of this board, no sound at all.
Anyone succeeded to plug a buzzer on a H7 type flight controller ?
Mine is connected to motor 5 on a KakuteH7Mini - works fine. Can you post your full parameters? I have a few here I can try…
Your setup is almost identical to mine - must be something simple
I flashed 4.2, put on your parameters, connected an active buzzer GND-GND, 5v-M8 - buzzer worked but inverted. Used regular alarm output and worked fine.
The difference is I use a Vifly which is a passive buzzer.
When you refer to “regular alarm output”, do you mean the buzz+/buzz- on the board or the param value 138 instead of 139 ?
Param 138
I am using a soter buzzer on this build which looks very like the Vifly buzzer
Right, it seems to be the same as a vifly. But I have Three cables on the vifly : 5V, GND (black) and a yellow wire (I assume PWM). What wires do you connect on your 5V, GND and M5 output ? I have the feeling you only use two of the three wires ? That might be a difference with what I’ve done (i connect all three wires : 5V on 5V, GND on Gnd and yellow on M8 output)
I connected in exactly the same way you did. On these you need the inverted alarm signal as they are designed to beep when the uart signal goes low.