Using M4 with BLDCs - Short How to

Info and discussion about the autonomous Micro FC, suitable for nanos, micros and mini multirotors

Re: Using M4 with BLDCs - Short How to

Postby aBUGSworstnightmare » Sat Jan 03, 2015 3:32 pm

Max wrote:Excellent, thanks. I'm going to use it with an r4 for now, but it would be cool if it worked with v2 as well. Yes, it's time to build something (with hardware)! :)

-Max


Hi Max,

the 'hardware' is ready but the weather here is bad (snow snow snow) :?
SANY0075.JPG
Christof's 300size frame with M4r5


More pics here viewtopic.php?f=25&t=3891&start=20#p29314
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Re: Using M4 with BLDCs - Short How to

Postby Max » Sat Jan 03, 2015 5:48 pm

Looks nice Joerg. No snow here, but cold... so I'm trying to make a 20cm quad to fly in the garage.

Just confirmed with Bill that we should NOT use any of the SPI pins (PA 5/6/7) from the expander on M4 v2 for analog inputs. So don't do that. :)

-Max
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How to us 4S (or more) LiPo's on the M4 expansion board

Postby aBUGSworstnightmare » Sun Jan 04, 2015 6:45 pm

Hey guys,

a lot of you have been asking me for 4S (or more) support on the M4 expansion board. I always had to say 'no' until today.

With some 'little helper' you can do it fast and easily, so elt me show you HOW TO do it.
ATTENTION: This only works with M4r6 (V2 production) boards since they have a dedicated I/O for LiPo voltage sensing (label is ADC). Sorry to the BETA guys (M4r5 or older) --> only 2S to 3S for you :?
SANY0082.JPG
Overview shot: M4r6 on 'aBUGSworstnightmare' M4 expansion board, 6V BEC, bluetooth module, Spektrum Sat with TX and last-but-not-least: 4S nanotech LiPo

You need a 'little helper' to use more than 3S: a BEC with 6V output 8-)
Here are some of them:
http://www.hobbyking.com/hobbyking/stor ... _Lipo.html
http://www.hobbyking.com/hobbyking/stor ... Input.html
...

I used this one - http://www.hobbyking.com/hobbyking/stor ... ction.html - for the proof of concept!
SANY0079.JPG
Jumper the uBEC to 6V output

SANY0085.JPG
When using the onboard Cypress RX or a Spektrum sat (like I did) you can solder the LiPo connector to the BEC directly

SANY0088.JPG
When using an external RX - i.e. Graupner/SJ HOTT (Orange RX shown for illustration only!) you should power the receiver from the BEC and crimp a cable to supply the M4 expansion board (signal line omitted for clarity!)

SANY0087.JPG
Bluetooth module is supplied from the 5V LDO on the 'aBUGSworstnightmare' M4 expansion board 0r3

SANY0083.JPG
M4r6 ADC input is connected to LiPo

SANY0084.JPG
Nanotech 6000mAh 4S LiPo (for those you still have doubts!)

4S on M4r6.PNG
Look at the flight battery shown in the QGC screenshot!!
Go and get a 6V BEC (and a M4 expansion board) and start flying the M4r6 on 4S +++

8-) Cheers! 8-)
Joerg
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Re: Using M4 with BLDCs - Short How to

Postby kinderkram » Sun Jan 04, 2015 7:07 pm

Good job, Joerg!
And as a proof of concept: what about 6s? ;)
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Re: Using M4 with BLDCs - Short How to

Postby aBUGSworstnightmare » Sun Jan 04, 2015 7:15 pm

kinderkram wrote:Good job, Joerg!
And as a proof of concept: what about 6s? ;)


No problem; the uBEC shown is 6S rated ;)
SANY0086.JPG
uBEC: 2S to 6S, 5/6V output voltage selectable (jumpered to 6V in the pic)


You can go to 12S if you want 8-) get a suitable uBEC (i.e. http://www.freakware.de/p/keto-hv-bec-1 ... 106722.htm) and start flying!
As long as the input voltage on the M4 expansion boards LiPo connector does not exceed 3S limit (7.2V would be better :!: ) you're fine!

But, since 6S is the limit for the M4
...
So to facilitate using High voltage supplies, the M4 V2 has a ADC port for voltage monitoring through a resistor divider to a Analog to Digital Converter (ADC). Supply main pack voltage on to this port to monitor up to 6S lipo voltages.
...

the one shown is good (and cheap/available).

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Re: Using M4 with BLDCs - Short How to

Postby sandmen » Sun Jan 04, 2015 7:29 pm

Hmm, and why not just using the one cell from the LiPo?
(Balancer connector)
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Re: Using M4 with BLDCs - Short How to

Postby aBUGSworstnightmare » Mon Jan 05, 2015 9:10 am

Hi Peter,

for sure an option to power the M4. Since some Graupner/SJ HOTT rx are operational down to 2.5V you will not have any problems when using 1S from the LiPo-balancer connector.

But - when using my expansion board - you will need 5V to feed the UART LLC (BT interface). So, if you want to use the BT connector this is no option in that case since you need to supply power to the expansion board.

O.K :idea: you can use 2S from the balancer connector to feed into the M4 expansion board LiPo connector and you're good to go :!:
It's even cheaper and adds nearly no weight (uses no additional space on the craft). Sorry, don't have a cable here to make a picture of such a setup.

Thanks for the hint Peter 8-)
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Re: Using M4 with BLDCs - Short How to

Postby Max » Mon Jan 05, 2015 9:19 am

Yea but then 2 things to connect to battery every time? I think I'd rather carry a small BEC/VReg, with 4+S accu the extra weight should be insignificant anyway. I've thought of this to power the M4 directly when flying with >1S (would also give you a decent voltage level indication w/out any external monitoring bother), but decided it would be a PITA to hook up for every flight.

-Max
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Re: Using M4 with BLDCs - Short How to

Postby aBUGSworstnightmare » Mon Jan 05, 2015 9:23 am

Max wrote:Yea but then 2 things to connect to battery every time? I think I'd rather carry a small BEC/VReg, with 4+S accu the extra weight should be insignificant anyway. I've thought of this to power the M4 directly when flying with >1S (would also give you a decent voltage level indication w/out any external monitoring bother), but decided it would be a PITA to hook up for every flight.

-Max


Well, in the end it's often a better of taste ...
I just wanted to point out there are multiple solutions how to use this little board in larger crafts/higher flight battery voltages.
You know, I have my own solution for larger crafts already:
SANY0025.jpg
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Re: Using M4 with BLDCs - Short How to

Postby aBUGSworstnightmare » Tue Jan 06, 2015 12:33 pm

Hey guys,

need your expertise with a problem I have when trying to use 3S Lipos on this Quad.



The Quad flies fine with 2S LiPos, but when I'm trying to fly with 3S - T-Motor 2206 should have no problem with 3S :evil: - the motors get hot after 8-10s of flight time (nearly burning out!).
The video shows you a comparison when using 2S and 3S; listen to the sound of the motors when on 3S. Flown in manual only.

I think the KISS ESC are causing the issue there, so what's your opinion?
The firmware and parameter file is enclosed. Tare and mag calibration performed. PID controller.
aqv7.0.r442.b1848-hwv8.5-ext_esc-vsense-pa6.bin.zip
r442 firmware file - PA6 for voltage sensing - use with M4r5 only!
(144.2 KiB) Downloaded 126 times

PARAMS_m4r5_q300-kiss_0r1.txt.zip
Complete parameter file
(2.35 KiB) Downloaded 156 times

Any idea what's the route cause?

EDIT: Was out in the garden with the 'lil sucker, powered by my rotten 4000mAh 2S Lipo (which I'm using since 2-3 years for bench testing/development).
Wanted to let you know that this craft flies excellent on 2S (with the parameter set posted). O.K. will have to check the Log-files since throttle factor can be improved a little but it's ultra stable, very agil and fun too fly with. Sorry, no video from the first flight, but I'm re-charging the LiPo and try to capture the second one on uSD :lol:
Will check HK stock in EU warehouse for a suitable 2S LiPo too.
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