Piezo buzzer for the APM 2.5

[seibernator]

Is it possible make one of these up and how would I go about doing it? I just need something audible to know when the board has been armed or dis-armed - a bit like the KK2 which I thought was a nice safety feature.

There doesn';t appear to be much on Google.

[DarrenG]

There';s this post over at RCGroups and this at DIYDrones.

I';ve just added the two LEDs as I had trouble seeing the ones on the APM and when the cover is on they';re out of sight anyway.  I used 10mm Ultra-Bright LEDs, works well and gives a nice visible ARM/DISARM status.

I also made up a Piezo buzzer but the click it makes is barely audible. Not sure if that';s a problem with the 5v Piezo buzzer I used, it was one i had in my bits';n';bobs box, or if it';s because it isn';t mounted on a panel. Hard to believe it would be that much louder when panel mounted though!

[seibernator]

Hey thanks for the info. The one from RCGroups looks very good. I managed to test the APM using a buzzer from a KK2. Two beeps for arming and one for dis-arming.

Am going to install an LED as well for GPS lock. Much better than guessing without picking up the quad or hauling my laptop to the flying site.

[DarrenG]

How loud was it?  Wonder if its worth me getting another piezo buzzer and retrying!

[seibernator]

It was loud enough to hear from about 10 - 12 feet away and maybe more. I have ordered another piezo buzzer from ebay as I need the one from the KK2 to stay with it.

Anything is better than hoping it has armed or disarmed without having to throttle it a bit to see it if has actually done it.

[DarrenG]

Thanks, will have to revisit this then as that sounds ideal. Must be the piezo buzzer I used was a duff ';un!

[Gaza07]

I might fit a buzzer to mine to nice find 
If you do fit a buzzer be sure to make it on a long lead and get it out on one of the arms the Rabbit flight controller came with a buzzer and very short leads and it was messing with the compass a lot   

[DarrenG]

Don';t know what I';m doing wrong here. Found another piezo buzzer, a new unused one, wired it up, plugged in and I get the clicks but they';re barely audible with my ear next to the beeper!

They can';t both be duff?

[seibernator]

Maybe they are 12v piezo buzzers and only make the clicking sound at 5v. The KK2 ones are 5v and ones I have ordered off Ebay are 3 to 24v so I hope they make some sort of sound.

[DarrenG]

Let me know how you get on.

[andycap]

You might find that you need a piezo buzzer with built in driver.  some, like ones you can get out of pc';s are just a piezo speaker and have no oscillator circuit built in.

Andy.

[seibernator]

The piezo buzzer I got off Ebay works very well. Nice distinctive double beep for arming and single for disarming. Come with its own drive circuit for direct connection to DC input:

http://www.ebay.co.uk/itm/Piezo-Buzzer-Sounder-3-24V-DC-85dB-/120660113013?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D7887431441599557826%26pid%3D100015%26prg%3D1006%26rk%3D1%26sd%3D120660113013%26

[DarrenG]

That';ll be why, no drive circuit in mine!

[andycap]

I picked mine up from MAPLIN.  Can';t remember the item code but I just looked on the shelves and found one that was a reasonable size and had a driver cct built in.  Cost about £2.50

Andy.

[sevet]

I recently understood that there are two kinds of buzzer, not sure which is which.
There is the what I think is the piezo buzzer which is actually sort of a speaker and can play multiple tones, this is not what you need for the APM.

The other is the Active buzzer which just beeps when you put some volts into it, you need the 5V one.
There is a howto in this forum on how to create a shield for it, to protect the apm, Its on Jumpy';s PDF manual as a sticky here.

I was lazy.... just connected the 5V active buzzer and it works (to A5), 2 beeps arm, 1 beep disarm, Long annoying beep for battery low (which is configurable to which voltage you want the beeping to start), I wish we could change it to like 3 beeps every 4 seconds and not the annoying long beep....

[Jumpy07]

I wouldn';t drive a buzzer directly.. you need something like below...  or you may blow the output on the APM

[attachimg=1]

[sevet]

On a 5V buzzer, why do we need this circuit? what is the danger? what can go wrong without it?

[DarrenG]

Can understand concern about brownouts etc if you';re relying on the ESC';s BEC for power, but if you';re using dedicated UBEC and not drawing power for anything else then it shouldn';t be an issue?

[Jumpy07]

Depends on size of buzzer..   the A* pins cannot switch a very big load..  and have no protection....you are switching the buzzer directly... its not like a servo.

This is nothing to do with UBEC /Power Module.. this is using the Analogue A* ports to switch a load.. in this instance a buzzer.

[DarrenG]

Ah ok, that makes sense, thanks.

[sevet]

On the APM 2.5 I have the buzzer connected directly without any shielding on A5 and it is working for while now.

I';m building a small Quad with the Crius AIOP v2 and when I test the voltage on pin 32 (which is actuall a pad on AIOP v2) i see 5v, when I connect the buzzer I get no beeps and measure 0v....

If this the problem the resistor is preventing?
The same buzzer on the Crius AIOP put on A6 which is a blinking led and I do hear a beeping sound, I had no luck trying to compile the buzzer for something like A8 which is free on v2....

Any suggestions? will a resistor make it work on pin 32?

[peter_a]

i see 5v, when I connect the buzzer I get no beeps and measure 0v....

Looks like pin 32 as been set up as a input pin with the internal resistor forcing that pin high.

[sevet]

Looks like pin 32 as been set up as a input pin with the internal resistor forcing that pin high.

Can you please explain what it means: forcing that pin high?

How do I move it from pin 32 to something like A7?

[peter_a]

Basically the AIO and the APM are just a  arduino mega 2560 with extra sensors and all the pin number are just standard arduino.

How do I move it from pin 32 to something like A7

To get any pin to work as a input or output it need to be set , so somewhere they is a define which sets which pin is going to be use for the buzzer and sets this pin as a output.
I will look to see it for you . it will look something like #define buzzer 32 and just change that to A7 or it`s pin number.

Can you please explain what it means: forcing that pin high?

By default the pins are input , which you can set a inbuilt resistor connected to the positive supply internal .
This is what you are seeing a 100k internal resistor connected to the positive supply   

[firey1]

Im using a lost plane buzzer i had spare seems to be working great

Have found that for some reason I havent worked out yet that it will come on when low battery as well
as my timer on the tx gets to about 3sec warning the buzzer starts as well
also if connected to the usb the buzzer goes as not enough voltage

only have the advanced param setting on 8

[DarrenG]

I';m getting the alarm when connected via USB, haven';t had the low battery alarm in flight yet, I';m relying on a low battery alarm connected to the balance plug and it';s conservatively set at the moment.

Presumably it';s the setting connected with the current&voltage sensor config in MP that triggers the buzzer?  Damned annoying when connected via USB!

[firey1]

yes it is Darren i just unplug now before connecting lol

I fly by time
10 mins flying leaves about 9.9 volts in battery