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Lightweight iOSD install

Discussion in 'General Discussion' started by ElGuano, Mar 5, 2014.

  1. ElGuano

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    I've been eying the iOSD mini for a while, but never pulled the plug because I was on the fence about the upgrade board or PMU-V2. They cost about the same, and there was no clear winner. I dropped 9g from my mainboard, so the upgrade board would have been ~17-20g heavier. On the other hand, the PMU-V2 was 28g by itself, but could probably be lightened up a bit. I went with the PMU thinking that if successful, I could cut out the BEC from my mainboard and run it as a pure PDB, else I'd have a workable PMU module if I transfer the Phantom's guts to a new quad.

    Turns out the PMU V2 can go from 28g down to a meager 8g. Whoa. The iOSD predictably drops from 16g to 4g. Paired together, that's 12g. With necessary connectors and wiring, 15g total.

    iOSD and PMU stacked to the right side of the NAZA.
    [​IMG]

    Four layers - RX, mainboard, PMU, iOSD. That's a lot of blinking red/green lights in a 1cm^3 volume.
    [​IMG]

    Final weight without batteries: 884g.
    [​IMG]

    With my 4400s, it's 1205g (looks like I may be looking for ways to shave off another 6g).

    With my 5400s, it's 1280g.
    At that weight, I think I'm officially off the market for a 3-axis gimbal. Just not gonna happen if it means going over 1300g.

    The iOSD is fun, now I don't have to draw out distances on Google Maps or guess how high I am. First test flight is hopefully tomorrow, if the weather cooperates.
     
  2. OI Photography

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    Was that just from removing cases and stock cabling, or did you trim the PCB's as well?
     
  3. ElGuano

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    Just the case and the stock cables. I was going to shave the pcb but there's no room on either component to do so, it's efficiently packed.

    The pmu has a metal case (it's so heavy I don't even think it'a Alu) that serves as a heartsick. I didn't need that since I wasn't going to daisy chain 6 canBus accessories to it. I also replaced the battery wires with thinner gauge, and removed the Naza connector since I was still using my main board as the voltage regulator.

    The iOSD's weight mainly came from the CANBus cable, which was excessively beefy and shielded.

    The bare components are 1/3 the as-shipped weight.
     
  4. gen3benz

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    Nice! Just soldered and mounted my iOSD and Rx yesterday. Looking at your setup, I would have gone with PMU instead of the upgrade board as well. That PMU case is a boat anchor :D
    I kept the iOSDs case but I may ditch it for a few grams.


    Would it be possible to remove the black plastic CANbus connector by desoldering and just solder all the connecting wires.
    I know I have seen a post with someone removing it but not jumpering.

    Edit....nevermind, you already did just that with the PMU and iOSD. Didn't look at the pic enough.
    What did you use to hold the boards together?
     
  5. ElGuano

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    The pmu is hotglued to the main board. The iosd is held to the pmu with 3m vhb. It's not a great bond because it's all chips and resistors so the contact patch is small. But I figure I'll need to move or work with the iosd in the future so I wanted it easily removable.
     
  6. gen3benz

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    Looks like I'm breaking out the glue gun tomorrow(later today...) P1 Rx isn't going anywhere for a while.
     
  7. OI Photography

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    Very cool, and it did take me a few min to trace and understand all your changes to the normal wiring configuration(s). I'd like to do the same thing in general, minus the PMU since I already have the board and will just stick with that. Unless I'm missing something, it doesn't seem like it would be worth it for me to add that now too even without the case.

    Tbh I'm not even going to add the iOSD mini till later anyway (i.e. after they're back in stock and I bother to buy one) so I'm not going to hold up my 1.5 upgrade for that. However, I'm going to try to mount my X8R receiver sans case when I do the upgrade, I'll post info on the weight difference between my naked Rx and a stock one.
     
  8. ElGuano

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    The only reason this was worth doing for me is because my Phantom mainboards already have enough weight carved off of them to make installing the upgrade board a +20g proposition:
    [​IMG]

    Normally, I'd wholeheartedly recommend the Sarawuth canbus mod with upgrade board, it's a no-lose proposition and extremely cost-effective.

    Taking components out of the shell is a great way to save space and weight, as long as you're mindful of shorts and interference. If your rx is one of those with individual wires per channel, there's an opportunity to cut some weight, but I notice that they're almost always braided to reduce noise/interference and I wouldn't want to mess with the RX too much :)