Double check my wiring

[demands]

Hi,

I was hoping maybe someone could have a quick look at a schematic I made, before I start soldering my tri...
Don't care about the actual placement/direction of sensors, I have another thread for that here viewtopic.php?f=6&t=574, I just want a confirmation on the wiring...

I won't be using a PCB, I will wire solder everything, and mount each BoB with tape or velcro...
Only sensors are covered by the schematic, I have a pretty good idea of how to connect ESC's and Rec to the Arduino...

Schematic is here:

• Is my schematic correct?
• Should I wire anything differently?
• Am I missing anything?
• Will this work with MW software?
• As I'm using A1-A3 for an analog acc, is there any features included in MW normally using these pins, which I won't be able to use with this setup?

I also have some questions regarding power mgmt...
On the "Connecting elements" page of MW site, the tricopter configuration has one ESC BEC powering the servo, and one ESC BEC powering both the Arduino and the Rec. The third ESC BEC isn't powering anything. Is this the recommended setup? As I see it, I have three ESC with built-in BEC, and three "parts" requiring 5v, the servo, the Arduino and the Rec. Shouldn't/couldn't the ESC BECs power one part each?? Or maybe it doesn't matter?
If anyone's interested, I plan on using Hobbyking SS Series 18-20A ESC, a GWS servo, a Pro Mini, and the Turnigy Rec (included with 9x, will be replaced by a FrSky telemetry once I feel confident the whole thing will at least lift-off )

Sorry for the newbie questions, but I haven't passed the newbie stage just yet

[Alexinparis]

Hi,
I think your schematic is correct.
I think the LLC is not mandatory here if you disable pullups in the arduino and rely on those from the bobs because everything is power up via 3.3V.

Regarding the use of ESC BECs, it is not advised to connect are the BEC together.
One a tri: one is enough for the servo, one is enough for all other parts (arduino, rx).
If you have a specific need for another device, you can use the unused BEC for this. no problem.

[demands]

Thanks Alex!

But I must ask, are you sure the LLC is optional??
The Arduino itself is 5v, and all sensors 3v3...
I risk frying my sensors if I connect I2C directly (as the Arduino uses 5v logic)... Or?
Does it hurt to have the LLC? I don't want to risk seeing magic smoke...
If I keep the LLC, should I enable Arduino internal pullup?

[mr.rc-cam]

But I must ask, are you sure the LLC is optional??

It is considered optional. But you must disable the Arduino's internal pullups via the related #define statement.

I risk frying my sensors if I connect I2C directly (as the Arduino uses 5v logic)... Or?

If you enable the 5V powered Arduino's internal pullups then there is this risk.

Does it hurt to have the LLC? I don't want to risk seeing magic smoke...

It will cause no harm to use it. But statistically more components, more solder points, and more wires means more things that can fail.

If I keep the LLC, should I enable Arduino internal pullup?

You could, but there are already pullups on the Sparkfun LLC so it should not be necessary. For example, my IMU uses a circuit that is a close clone to the Sparkfun. I've tried both ways and did not experience any reliability problems so I disabled them.

I see that your 3.3V Vreg is powered from D12. Be sure that the total current draw of your entire sensor circuit is less than the Arduino's output current source spec.

[demands]

Ahh, thank you as well mr.rc-cam!
Now I understand it better...

Regarding the current draw, can anyone tell me the (approx) peak current draw of a WM+?
That would be very helpful, as I don't have a working amp-meter at the moment...
The rest of the circuit (all sensors except WM+) should have a peak below 15mA (calculated, not measured), and the digital pin on the Arduino outputs 40mA...
Unless the WM+ draws very much, I think it should be safe...

[demands]

Ok so I've thought some more about this...
#1, the FAQ states it should be fine to power the WM+ with 5v as it has a built-in regulator.
#2, the FAQ states the WM+ should be the only sensor which may be required to reset through pin 12.

So, my new thoughts are, and I wonder if this is a better/worse/does not matter setup:
Power the WM+ only, through pin 12 (5v) directly.
Power the 3v3 sensors through the LM1117, fed by Arduino VCC (regulated 5v). Or should it be through Arduino Raw (i.e. what ever goes into raw, coming from ESC).

From my previous image, I start wondering if the LLC (if i decide to keep it) should really be fed through Arduino Raw (i.e. directly from ESC). Or should it be fed from Arduino VCC, regulated 5v? And since the ESC should provide regulated 5v (or am I wrong?), why not feed it into Arduino VCC instead of Raw? And, if I loose the LLC, should I power the sensors from Raw or from VCC?

Tired and confused, probably shouldn't be thinking of this at 1AM...

[demands]

Bump
Would very much appriciate some feedback on my last post...
Got my last parts from HK and ELFA today (feels like christmas ) so I'll start assembling soon...
My biggest questionmark is when to use Raw and when to use VCC (on a 5v Arduino)
Shouldn't the power from the ESC BEC be regulated 5v (thus, it should not matter)??

Here's an image which I think describes the changes I explained in my last post:

If using LLC:
- Should the LLC HV come from Raw or VCC??
- Should the 3v3 Regulator be connected to Raw or VCC??

If NOT using LLC:
- Should the 3v3 Regulator be connected to Raw or VCC??

[Alexinparis]

So, my new thoughts are, and I wonder if this is a better/worse/does not matter setup:
1) Power the WM+ only, through pin 12 (5v) directly.
2) Power the 3v3 sensors through the LM1117, fed by Arduino VCC (regulated 5v). Or should it be through Arduino Raw (i.e. what ever goes into raw, coming from ESC).

1) ok, this is a well known working setup, except for some copies that don't accept 5V.
2) I would say powered by the arduino VCC because it should be a more stable volatage, and there is nearly no Amp requirements.

[demands]

Thanks Alex, I've now tested this setup on a breadboard, and it seems to be working really nice!