Multiple connection on FTDI

[Tjay2365]

Hi guys,

Just finishing off my new Hexa and wondered if the Autoquad ftdi would support powering both a 3DR Telemetry radio and a JD ioboard (and maybe a Minim OSD) without resorting to a separate power supply? I'm not sure on what the power requirements are for these boards are without measuring them but wondered if it would be safe to do so?

Thanks,
Tony

[bn999]

Do you have a combined current estimate? If you are not powering ESC's from the FC, you have a fair bit of current available at that connector.

[Tjay2365]

Hi Bill,
Thanks for the quick reply.
No I'm not powering the ESC's from the FC as it's connected to them via the signal wires and earth only. The JD ioboard is being used for the led lighting (MAV2HOTT) and the led strips themselves powered via a separate ubec. The only things the FC is going to power is the 3DR telemtry transmitter, the JD ioboard (aduino) and maybe another Minim OSD (arduino again?) so I doubt the power requirements are very high but just wanted to check before I go ahead. What is the safe max current you could draw from the FC out of interest?

[kinderkram]

Menno is doing this for longer, mine is also working with the ESC32s powered by the FC:



If in doubt, you could pick up the 5V for a second unit elsewhere.

[Tjay2365]

Looks like I should be fine. Thanks for the picture, very helpful.

Cheers guys

[kinderkram]

Easiest way is to simply use 2 of those double row 3pins like the motor connectors and solder them from both sides.

[Max]

Personally I've found that powering any kind of Tx via a separate voltage regulator (or UBEC) introduces less noise in the AQ sensors, especially MAGs. This is easy to spot in logs/telemetry. Maybe the extra noise gets filtered out or is otherwise insignificant, but I figure it can't be helpful. Even just a ground+signal connection between AQ and Tx introduces some noise, but less than if power is also routed. YMMV, but I've seen this on all 3 of my AQs and with several different BT and 3DR transceivers. With BT it's fairly minor (can see the LED blinking in the MAG plots for instance, but not much else), but with the 3DR things were worse in my setup.

Might be worth some experimenting. Here are a couple screenshots I dug up, to illustrate.

-Max

BT module powered from AQ - module on (LED blinking), then off (disconnected), then on again (LED blinking) then BT connects at the end (LED steady on).

BT module powered via external vreg. - off/on/connected, no obvious difference in plot.

[kinderkram]

But this is a general problem: mounting the units and routing the wires away from the sensors.
Or does your post refer to the multiple connections and you´re suggesting NOT to do it?

[Max]

It's "general," true, though unit position or wire config (twisting, routing, etc) doesn't seem to affect the result (I tried). Multiple units could possibly exacerbate the problem. Just suggesting something to check.

-Max

[Tjay2365]

Interesting stuff and food for thought Max.

I'm now thinking aong the lines of making a distribution board out of veroboard and powering the power connections from a 5v regulated UBEC and bring the tx rx lines down to that from the FC for the other boards to connect to. Hope that makes some sort of sense.