Hello again.
A small update of my project (a part of it... ;))
Here we go, my A.A.P.D.B. - Alternative Arducopter Power Distribution Board
Simple double-sided board with extra kick.
It can handle 4 ESC's and a battery monitor. And the most important high current!!!
Above is the board before etching.
As you can see the board is VERY simple but there are some cool features:
1. On the top side of the board there is a mesh connected to negative pole for ground providing and it acts as shield for PWM signals and for other electronics above the board like the APM, compass, x-bee, GPS etc...
2. Small 2 pin connector for direct battery connection, good for LED strips and battery monitors like this one from HobbyKing
3. All 4 PWM signals combined in ONE socket as well positive and negative wires from ONE ESC.
4. And 4 mount holes.
Some more pics from the making process:Etching!!!
Comments
Plenty of systems have already some diodes for protecting purpose.
Vth is around 0.7V máx usually so it could be acceptable. Some diodes as low as 0.2V.
Beside, if BEC is 6V (not rare) the thing becomes easier to get a 5ish voltage.
Anyway precision is not upper important for servos and electronics usually have their own regulator.
@ I.S.
Voltage drops on the protection diodes will kill that idea...i.e. 5 V in becomes ~4 V out. Op amps and FETs have very high input impedance.
Automatic power source selection may require further electronics involved.
Arduino boards choose automatically between external and USB power using just an opamp as and a FET.
I find this solution ok, but., it wouldn't be easier to put just an output diode in each BEC output and then tie all the outputs together?
This would avoid current from one BEC entering another and always highest voltage BEC output would be "selected".
If one BEC fails and gets shorted, the rest of the circuit shouldn't care because it's isolated by its own diode.
Is this solution implementable? Or am I missing something?
regarding inputs of the becs, I'm not entirely sure of the components involved, but for example on my rangevideo osd, it has dual power inputs and with a jumper setting it can be set to auto switch between the inputs, choosing the better voltage level. so if one dies...:( the other takes over automagicly and output power doesnt even see a bump. I also saw the dual bec on hk as well, so couldnt be that much involved, but I'm not that good on electrical engineering so wouldnt know where to begin. Really I was just wondering if you had intentions in that regard, since I see power input pins on all 4.
Hi,
Looks very nice, certainly an improvement over my mess :)
I'm curious why you only connected the signal wires on the ESCs and not the ground?
I agree with not hooking in the 5v, but it seems to me that 3 of the ESCs have no ground reference this way?
Bart
I asked myself that several times.
Putting several BEC together in parallel may seem to make a failsafe redundant system.
However... connecting several regulators in parallel may not be a good idea cuz current flowing back and forth different regulators and other issues,
AND, if one BEC fails with a shortcut it may put down the other BEC wired in parallel.
So, it's a smart or dumb idea to put BECs in parallel?
I don't have even tested anything so I am just guessing.
If just happens that one ESC blows, your pretty much dead in the water yes?.
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