[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Paparazzi-devel] Power supply question

From: Adam Spence
Subject: Re: [Paparazzi-devel] Power supply question
Date: Mon, 19 Jul 2010 14:31:34 -0500

Hey Neel,

The problem exists as the Tiny was only ever designed to drive a Tiny airframe... by that it means a Funjet or smaller. In this instance it would have two small servos and the power requirements for the servos would be small.

The power supply on the tiny itself is limited and it is this 5v regulator which will be driving the servos. As a result putting too much load on this regulator the power supply will drop and you'll actually trip the brown out voltage on the tiny. This will result in a reset of the autopilot in the air... really not desirable!

Someone else may be able to quote the rating of the power supply but it will all depend upon your chosen modem, your size of airframe, choice of servos (digital servos are power hungry) and how free your control surfaces are (if you're control surfaces are tight you will waste energy overcoming the friction/sticktion).

If it's anything bigger than a Multiplex Funjet which has 2 small servos and runs a modem which is power hungry (>50mw) I would recommend having the separate power to the servos (and maybe even the modem). The last thing you want to happen is for the autopilot to brown out and you loose control over everything.

There was a thread earlier on today which went through the separate design for powering the system.

If you do insist on powering all of the servos from the tiny, measure the current consumption of the entire system from the battery whilst transmitting with the modem (at full power) and moving all of the control surfaces. If you can force the servos to stall (which they should not) this will give you a worse case indication of the power requirements of the system. If this is below the rating of the power supply (you should have a margin in there too) then you might be OK to proceed.

Hope this helps and it's not all rambling!



On 19 July 2010 14:16, Neel Mehta <address@hidden> wrote:
Hi all,
I'm quite new to Paparazzi as in I have still not purchased a PPZ system but have looked through the Wiki and the archived threads. I already have purchased an airframe, power system, RC equipment and am now ready to jump in and invest in an autopilot.
The question I had about the PPZ system is regarding the power supply architecture. The schematic at the Wiki ( shows the Tiny board powering the servos and RC recevier. However, I stumbled across some threads that said it would be wiser to power the servos and receiver through a separate BEC rather than through the Tiny. From experience, can someone tell me which approach worked well for them?  Are there are any pit falls with powering the servos, receiver through the Tiny that I should be aware of?
Any inputs are much appreciated,

Paparazzi-devel mailing list

reply via email to

[Prev in Thread] Current Thread [Next in Thread]