YAY, First Multirotor Build!!!
- Thread starter pootman
- Start date
Droider
Drone Enthusiast
I ordered a I2C Octo Isolator R3 when I placed my initial order for the MK stack. After reading about the installation, it looks like it'll be though to install with a DB. I was wondering if it's worth the effort? How often does total power failure on all motors occur? I'm thinking about returning it for credit, but will install it if it's worth it. What's the consensus?
http://shop.quadrocopter.us/I2C-Octo-Isolator-R3_p_266.html
Lance
http://shop.quadrocopter.us/I2C-Octo-Isolator-R3_p_266.html
Lance
Droider
Drone Enthusiast
Sounds like a load more connectors to fail.. IMO if the if the MK dis board to made well and regular checking is carried out there should be no problem.
There is always the chance that something is going to fail. I have yest to see a video of any multirotor surviving a motor failure.
Hope some one can post a link.
DAve
Dave
There is always the chance that something is going to fail. I have yest to see a video of any multirotor surviving a motor failure.
Hope some one can post a link.
DAve
Dave
The I2C isolator board keeps a short downstream of itself from locking up the entire I2C bus as it will if all devices share the same path to the flight controller like they do attached to the PDB. By putting the board in line between the F/C and all of the BLs, a failure of any one BL will not effect the commands going to any of the others since the isolator effectively puts each BL on its own circuit.
Now how useful the isolator board will be depends a lot on how many motors you have, if its a quad, don't bother as the failure of a motor for any reason, I2C bus or not, is going to send it to the ground really quickly. On a Hexa, you may or may not have enough control to get it back on the ground if a motor fails, some people say its possible, others say it isn't. Personally I haven't experienced or seen anything to convincingly confirm either opinion although I do have an isolator board in my Droidworx Hexa.
It IS a well known fact that an Octo can survive loss of a motor and continue to fly, so in that case the isolator board is absolutely worth having as it can mean the difference between an expensive pile of broken bits and an Octo that just needs a BL replacement or repair.
Of course if you're using an I2C converter and standard ESCs with an MK flight controller then the isolator is of no use at all because the only thing on the I2C bus downstream of the F/C is the converter, and if it fails you're done regardless.
Ken
Now how useful the isolator board will be depends a lot on how many motors you have, if its a quad, don't bother as the failure of a motor for any reason, I2C bus or not, is going to send it to the ground really quickly. On a Hexa, you may or may not have enough control to get it back on the ground if a motor fails, some people say its possible, others say it isn't. Personally I haven't experienced or seen anything to convincingly confirm either opinion although I do have an isolator board in my Droidworx Hexa.
It IS a well known fact that an Octo can survive loss of a motor and continue to fly, so in that case the isolator board is absolutely worth having as it can mean the difference between an expensive pile of broken bits and an Octo that just needs a BL replacement or repair.
Of course if you're using an I2C converter and standard ESCs with an MK flight controller then the isolator is of no use at all because the only thing on the I2C bus downstream of the F/C is the converter, and if it fails you're done regardless.
Ken
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I have seen both a Hexa and an Octo fly minus one motor though neither one was an MK, if I can find the links and the videos are still on the web I'll post them. Doesn't mean any or all hexa will fly that way, I imagine the RTF weight and a lot of other factors come into play there. There have been many reports of Octos flying minus a motor and some video, I do believe they will retain enough power and control response for a safe landing minus a motor. I think a Hexa would be more like a controlled crash, sort of like losing the tail rotor on an RC heli and having to hit throttle hold and auto it down with no yaw control.
Ken
There's a couple ways to do it, you can solder header pins to the BLs in place of the C & D connections and use servo cable with the appropriate connectors on both ends or do like I did and solder some small gauge noodle wire to the C/D connections on the BL and then crimp a servo connector on the other end for the ISO board. I installed the board itself in the stack between the Navi and GPS, could have put it below the Navi if I had just made longer ribbon cables to connect the F/C to Navi and might eventually get around to doing that.
To make up for the loss of the C & D connections as a mounting point for the BLs I just used a few drops of CA around the edge of the BL to hold it to the PDB, no problem so far in several hours of flight time and it should be fairly easy to separate the two with a small xacto saw if I ever need to replace a BL.
The picture I posted earlier was the first incarnation of the Iso board setup when I had it installed in my stock MK Hexa prior to swapping all the electronics to a Droidworx frame. I'm just about to order the necessary bits to make the rebuilt stock Hexa into an Octo2, that one will get an Iso board as well as I'm mainly making the change for the redundancy factor and ability to get it down in one piece in the event of losing a motor in flight.
Ken
I bought two Turnigy 4s 5000mAh 40C packs. I'm planning on running them in parallel for 10000mAh total cap. I think I read somewhere that that should give me 10-12min flight times. I tested a couple of my motors with a standard ESC and 4s packs. The motors are pulling 23amps WOT.
Hi Ken,
I haven't worked on my octo in more than a week now due to work taking all my time. I'm starting to take another look at it and had a couple of follow up questions about the isolator board.
1. Do I still power the BLs via the main power plug on the PDB?
2. If so, then do I simply pull power from the PDB (looks like there's a couple of pos and neg solder points) to power the FC? Then power the isolator board using 5v and GND from the FC?
Thanks again for all your help!
Lance
I haven't worked on my octo in more than a week now due to work taking all my time. I'm starting to take another look at it and had a couple of follow up questions about the isolator board.
1. Do I still power the BLs via the main power plug on the PDB?
2. If so, then do I simply pull power from the PDB (looks like there's a couple of pos and neg solder points) to power the FC? Then power the isolator board using 5v and GND from the FC?
Thanks again for all your help!
Lance
My attempt at flying it yesterday almost ended in a flip! I scratched my head and went to bed. Someone suggested I recheck my motors for correct directions and I thought, "you gotta be kidding, I've looked those motors over and checked the direction of rotation a bunch of times! Ain't no way they're backwards!!!". Well, this morning I ran a motor test via mktools and when I got to motor number 5, IT WAS BACKWARDS!!! Guess all my other checks sucked. Oh well. Glad it's flying and hope to refine my aerial videos as I progress with this project. Thanks for all the help that's been giving by everyone on this forum.
First onboard video (a little shaky at times)
http://www.youtube.com/watch?v=4e3zHPFtSAI&feature=youtube_gdata_player
Lance
First onboard video (a little shaky at times)
http://www.youtube.com/watch?v=4e3zHPFtSAI&feature=youtube_gdata_player
Lance