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Jun 12, 2021, 03:29 PM
RC-addicted
Serge Roth's Avatar
Only, if you can live without smartaudio and that silly wifi function
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Jun 13, 2021, 05:24 AM
Registered User
Yeah - smartaudio shouldn't be a problem - I can just use whatever channel and band I want cause nobody else will be around.

needs a step-up though eh? I'm thinking the GPS will fail below 3.3V?
Jun 13, 2021, 08:58 AM
RC-addicted
Serge Roth's Avatar
I could not do without smartaudio, changing the vtx output while flying via the tx is waaaaaaay too useful
Jun 13, 2021, 03:21 PM
If it flies, I can crash it.
rocketsled666's Avatar
You can run SA on softserial using almost any other IO pin. I've used the LED pin on some quads for this, since I wasn't running LEDs but I needed another serial port. Also, most FCs have a Motor 5 and Motor 6 connection someplace that can be borrowed if you're using the FC on a quad...

Also, you can use CMS to change VTX channels remember, provided you know what channel it's on to begin with so you can tune in to see what you're doing. Although, if your RC TX supports TextGen, you can access the CMS system without a functioning video display...
Jun 13, 2021, 06:39 PM
Registered User
Quote:
Originally Posted by ptwenty
Yeah - smartaudio shouldn't be a problem - I can just use whatever channel and band I want cause nobody else will be around.

needs a step-up though eh? I'm thinking the GPS will fail below 3.3V?
All 1S FCs have a step-up regulator already. Its how they provide 5v for the receiver, and also how they keep a stable 3.3v for the MCU. The problem is that they are usually low current, and when the voltage gets below 3v they can no longer provide the current required by the VTX when running at high output levels. The GPS draws hardly any current, same as the receiver, so they will be fine all the way below 3v

And as Serge Roth discovered, if you use SmartAudio to reduce output power to 25mw once you are under 3v, you can keep going all the way down to 2.6v without brownouts
Jun 14, 2021, 01:27 AM
Registered User
Quote:
Originally Posted by Tokyo_Dom
All 1S FCs have a step-up regulator already. Its how they provide 5v for the receiver, and also how they keep a stable 3.3v for the MCU. The problem is that they are usually low current, and when the voltage gets below 3v they can no longer provide the current required by the VTX when running at high output levels. The GPS draws hardly any current, same as the receiver, so they will be fine all the way below 3v

And as Serge Roth discovered, if you use SmartAudio to reduce output power to 25mw once you are under 3v, you can keep going all the way down to 2.6v without brownouts
Thanks, I might have a go at adding one then.
Jun 17, 2021, 10:21 AM
RC-addicted
Serge Roth's Avatar
Someone send me a PM to ask about the installation of a buzzer:

I use those on my quads, they work fine even if the battery of the quad is pretty low, under 3 volts.

Soldering is not too finicky, see picture 1, and I have used a small cable-tie to fix the buzzer to an arm, see picture 2.

BTW, I HIGHLY recommend to secure the battery in case of a crash, I have spend two hours to find the quad in knee tall grass, and another 30 minutes for the (green) battery. It was an area of about 50 by 50 meters, and it was mere luck that I have found both. I use a battery strap from Betafpv to do the job, see picture 3.

Oh, and I recommend (yes, I know, shameless ) my modified bottom housing, it's 2mm taller that the original, more space for the stuff, and better cooling.
Jun 17, 2021, 03:00 PM
Registered User
Thank you so much. With the buzzer does it just have two wires, and is it just 5v and GND you use on the FC?
Jun 17, 2021, 03:59 PM
If it flies, I can crash it.
rocketsled666's Avatar
Buzzers come in two varieties - ones that are "passive" and depend on the drive voltage/current of the FC's digital output pin to make them work, and ones that are "active" and take a separate 5V input that is used with a dedicated driver built on to the beeper. The active type is usually a good 10-15db louder than the passive type. In my experience searching for quads in the tall grass, the passive beepers are not really loud enough for a good direction fix unless you're pretty close already. I only use the active kind, Matek's brand has been pretty good.

Note, my advice is that you mount the beeper so it's pointed up when the quad is upside down. I don't know why it is, maybe a function of the toast-always-lands-butter-side-down law of physics, but my quads almost always end up upside down in a crash. When I stupidly had the beepers on the top side of the quad, I had trouble finding the things in spite of the extra loud beeper.
Jun 17, 2021, 07:22 PM
Registered User
Quote:
Originally Posted by rocketsled666
Buzzers come in two varieties - ones that are "passive" and depend on the drive voltage/current of the FC's digital output pin to make them work, and ones that are "active" and take a separate 5V input that is used with a dedicated driver built on to the beeper. The active type is usually a good 10-15db louder than the passive type. In my experience searching for quads in the tall grass, the passive beepers are not really loud enough for a good direction fix unless you're pretty close already. I only use the active kind, Matek's brand has been pretty good.

Note, my advice is that you mount the beeper so it's pointed up when the quad is upside down. I don't know why it is, maybe a function of the toast-always-lands-butter-side-down law of physics, but my quads almost always end up upside down in a crash. When I stupidly had the beepers on the top side of the quad, I had trouble finding the things in spite of the extra loud beeper.
Actually i'm quite sure passive/active means something different.
Active buzzers have an integrated circuit that generates the buzzer tone. They will beep whenever voltage is applied to them (and this is the type needed with most flight controllers)
Passive buzzers have no integrated circuit, and hence need a driver circuit to generate the beep tone. But that circuit could also generate different frequency tones for a bit more variety in the beeps. You could have this playing melodies for instance. Buzzer driver circuits (chips) are quite simple though.

If you connect a passive buzzer to a flight controller buzzer output all you will get is clicking, no beeping.
Jun 17, 2021, 08:51 PM
Registered User
Yeah I think that’s what he was saying about passive needing a digital (toggling) signal to generate a tone.
Jun 17, 2021, 10:22 PM
If it flies, I can crash it.
rocketsled666's Avatar
Yeah, maybe. I can't say I've actually looked at the driven signal to see.

I have two types of buzzers. One requires only two connections - one to V+ and one to the BUZZ- on the FC. The other type requires 3 connections - one to V+, one to V- and one to BUZZ-. The second type is much, much louder. That's because the current to drive the buzzer is being sunk through the dedicated ground connection (and the on-board driver chip), where in the two-wire type the current has to be limited to what the open collector output of the FC's output pin can safely sink, and that's going to be a lot less...

I've always just assumed the two-wire type was being driven by a toggling output and the three wire type has a resettable one-shot that maintains a constant signal to control the beeper even though the input is toggling.

But I'm perfectly happy to accept the facts if I'm wrong.
Jun 17, 2021, 10:50 PM
Registered User
I think the three wire ones just utilize much bigger buzzers (and in fact, they might be the passive ones). So there would be circuitry in them to generate the buzzer tone.

Also, i suspect that those three wire ones (I dont have one, but i see the ones with the inbuilt batteries) have a bit more smarts to them - the battery backup ones will beep when disconnected from the battery for instance, and also when the battery voltage gets too low - even if the FC signal isnt telling it to beep

The other bits about what constitutes an active and passive buzzer i am certain of though. You can get both active and passive buzzers in the simple cilinder shape, and if you get the passive one, they wont do much when connected to the FC
Jun 17, 2021, 10:56 PM
If it flies, I can crash it.
rocketsled666's Avatar
No, the size of the buzzer itself is the same. In fact, they look like identical parts, with the only difference being the loud buzzers have a small PCB they're attached to. But the rear end of the two-wire type has some epoxy potting, suggesting there might be an active component in there.
Jun 18, 2021, 01:10 AM
Registered User
Quote:
Originally Posted by rocketsled666
No, the size of the buzzer itself is the same. In fact, they look like identical parts, with the only difference being the loud buzzers have a small PCB they're attached to. But the rear end of the two-wire type has some epoxy potting, suggesting there might be an active component in there.
Hmm then it could be a matter of current driven through them, though i think the buzzer output on flight controllers always goes through a transistor so the output should be the same. Perhaps they are just better quality buzzers? I see some are listed on aliexpress as 100db, others at 110db.

I have a little 9.5mmx5mm cylinder buzzer that i got from an old toy transmitter that i was going to use in my nano LR, it currently has a 12mm buzzer which, although quite loud, also weighs 1.6g. They both have epoxy covering the rear, however the smaller one is unfortunately a passive buzzer, and just clicked when attached to my FC


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