Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 (13-Jan-2021, 04:17 PM)kaitylynn Wrote: Love my SAM-M8Q! It is one of the fastest acquiring GPS modules that I have installed on any of my craft. I use it on The Japalura as that is a free style craft and it will never be considered for INAV.
In terms of weight, they both weigh about the same when actually set upon my scale. Both weigh in at 7.4 grams sans wiring, but both have shrink tube casing. Yes, I'm not debating the quality of the Matek GPS, they are solid. My question was if saving a gram or 2 for a equally great performing GPS was worth it. I'm not focused on weight savings at that level, and if it is like racing motorcycles, bicycles, etc. every ounce for them so every gram for a micro quad might be important. If not, then it doesn't matter. Also, if low weight is the ultimate goal, is it to only be just under 250g, or is it important to be even lower to be able to get more battery, etc. If Harry is looking to reduce weight so much that he is considering going to other frame materials, I would think a loss of a gram or 2 might be important for equal performance. Also, still curious what the BEC is being used for on the micros that can't be powered without it.
Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 (13-Jan-2021, 03:35 PM)Krohsis Wrote: So Harry, what are you using the BEC for?
Also, given you can get lighter GPS pucks than the Matek, is it more important to you to have a Matek GPS or save a gram or 2? And on the issue of weight savings, is lighter also the metric you look for or if you can stay under 250g, will performance/reliability be what you look for? Will you go for the lightest components to carry a heavier batt? Hi Krohsis, The BEC will be used to power the GPS unit independently of the FC for faster satellite acquisition. This is one of TMac's suggestions {see video}. The weight is less than 1 gram {it doesn't even register on the scales} so it really won't add much to the build. On the other hand, quickly acquiring satellites is important to me because I don't want to be waiting around for a satellite fix at any one location. I want to be able to arrive, get the quad in the air as quickly as possible, fly, return, and leave. ![[-]](https://intofpv.com/images/collapse.png) • Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 (13-Jan-2021, 04:33 PM)iFly4rotors Wrote: Hi Krohsis,
The BEC will be used to power the GPS unit independently of the FC for faster satellite acquisition.
This is one of TMac's suggestions {see video}. The weight is less than 1 gram {it doesn't even register on the scales} so it really won't add much to the build. On the other hand, quickly acquiring satellites is important to me because I don't want to be waiting around for a satellite fix at any one location. I want to be able to arrive, get the quad in the air as quickly as possible, fly, return, and leave. Ok, I understand, makes sense, thanks. I will say if the Matek can't acquire 10+ sats in 30 seconds or less without separate power source, maybe it's not as good as I thought. But if less than a gram and not a big space user then no biggie except for additional component failure.
Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 Hi Krohsis,
In my area the Matek M8Q-5883 takes more than 30 seconds...more like a minute or two {not sure exactly, but it is longer than I like}.
If I can get that time down to a few seconds, the satellite fix will be acquired by the time I can get my goggles adjusted and ready to take off.
I have already constructed the wiring on my 7 inch builds, but, as you know, neither one is complete yet. Posts: 1,529 Threads: 49 Likes Received: 720 in 531 posts Likes Given: 481 Joined: Oct 2020 Reputation: 93 I wire my GPS to the 4v5 pad on my FC (ie a pad that is powered when connected to USB). This allows me to ensure a warm/hot start when I get out to the field by plugging it into a USB power supply for a min or two until it gets a solid lock. It also makes bench testing much easier! Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 Hi V-22, Are you referring to the 4.5v pad that some FC boards have to power the Rx receiver? What FC are you using ?? Some FC boards only have 5V pads {which are not powered by the USB connection} and do not have the 4.5v pad; it just depends on which FC you have. I have used a small "extra" battery to power the quad for a few minutes before switching to the main battery which does work, but it still takes a couple of minutes. My goal here is to reduce the satellite fix time to a matter of seconds rather than minutes. I don't want to spend any more time at a fly location than I have to. Get in, Fly, Get out; as quickly as possible. Fly it like you stole it.  I will be there long enough just flying. So far, I have not found any decent fly locations; some of the more promising might be marginal for spending a lot of time at. You know, parked on the side of the road or out near private property. I am not yet brave enough to try the beach which is actually pretty narrow where we live.  • Posts: 1,529 Threads: 49 Likes Received: 720 in 531 posts Likes Given: 481 Joined: Oct 2020 Reputation: 93 Yes. Sometimes it's not labeled, but you can probe with a multimeter while the FC is connected to USB and see which 5V pads have power. Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 (13-Jan-2021, 05:23 PM)V-22 Wrote: I wire my GPS to the 4v5 pad on my FC (ie a pad that is powered when connected to USB). This allows me to ensure a warm/hot start when I get out to the field by plugging it into a USB power supply for a min or two until it gets a solid lock. It also makes bench testing much easier! Yeah different GPS pucks are different. I use the same on all mine and in less than 30 usually around 15 seconds I have at least 10 sats.
• Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 Thanks for the info, Harry.
I got a 3 inch frame free with another frame and components I ordered a couple years ago. That frame went in a box on the back of shelf and I never planned to build anything with it. But since little ones are all the rage I will follow your tutelage on your posts and learn something. Maybe I will build one for a LR platform.
Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 (13-Jan-2021, 09:33 PM)Krohsis Wrote: Thanks for the info, Harry.
I got a 3 inch frame free with another frame and components I ordered a couple years ago. That frame went in a box on the back of shelf and I never planned to build anything with it. But since little ones are all the rage I will follow your tutelage on your posts and learn something. Maybe I will build one for a LR platform. Hi Krohsis, It will be interesting to see your 3 inch build; looking forward to it.  I will keep updating the first post in this thread until I get the build completed. I have also added links to other 4 inch long range builds that others have done or are working on; that will make it easier for me and others to check the other members builds as well. As you may know, My Journal contains an index to all of my builds. You can also PM me with questions.   Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 (13-Jan-2021, 11:26 PM)iFly4rotors Wrote: Hi Krohsis,
It will be interesting to see your 3 inch build; looking forward to it. It will be a bit. I have my FR10-G to complete. And then my 10 inch screamer I hope to break 150mph with. Maybe after they are done, I will do my 3 inch. It is a 3 inch frame, but I will try to get 4 inch blades on it.
• Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 (14-Jan-2021, 12:03 AM)Krohsis Wrote: It will be a bit. I have my FR10-G to complete. And then my 10 inch screamer I hope to break 150mph with. Maybe after they are done, I will do my 3 inch.
It is a 3 inch frame, but I will try to get 4 inch blades on it. Hi Krohsis, That is entirely possible. As you know, I am running 4 inch props on an "enhanced" 2.5 inch GEPRC Phantom frame. When you get around to working on it, send a picture of the frame. Posts: 5,966 Threads: 47 Likes Received: 2,798 in 2,259 posts Likes Given: 7,776 Joined: Jul 2019 Reputation: 97 So here is the list of build components. It is everything in the electronics package and drive train,
but does NOT include ANY frame, mounting hardware, or additional wiring harness.
Component weight (grams)
iFlight Beast H7 55A AIO (26x26 whoop).................. 9
Panasonic 1000uf 35v ............................................ 5
FrSky R9MM with T Antenna ................................... 3
HGLRC Zeus 25,100,200,350 mW ............................ 1
Foxeer Razer Nano 1200TVL 4:3 .............................. 5
VAS Minion Pro ....................................................... 6
Matek GPS SAM-M8Q .............................................. 8
FullSpeed Lucky Box w self power battery ................ 4
iFlight 5V BEC ........................................................ 1
The total weight for this electronics package .................................. 42 grams
This is pretty much what I expected.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The total weight for all 4 motors with wires and bolts ..... 56
The HQProp 4 inch props .............................................. 7
The total weight for the drive train (less extra wiring) ..................... 63 grams
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ____________
105 grams
This is 105 grams with out a Frame, hardware, or wiring harness.
Right now I am exploring options for a frame.
It looks like my 130 to 135 grams is going to be close. • Posts: 164 Threads: 10 Likes Received: 95 in 71 posts Likes Given: 172 Joined: Dec 2020 Reputation: 4 Hey ifly4rotors, are you still running 5” props? I didn’t see 5” in the thrust tables, although I’d think you’ll get higher efficiency over 4”... And wow, your capacitor and your camera are the same wight!!!  • Posts: 3,533 Threads: 265 Likes Received: 2,610 in 1,545 posts Likes Given: 3,893 Joined: Feb 2018 Reputation: 78 15-Jan-2021, 01:06 AM (This post was last modified: 15-Jan-2021, 01:31 AM by Krohsis.) Joshua makes a good point. With a 2s system why go with such a big cap? I don't know if there is any weight savings, but you clearly could drop the cap voltage size by at least 10 if not 15 volts, perhap more given the low voltage of 2s. Also, I don't remember the formula for caps and noise reduction vs voltage etc. But there is a difference. You may want to drop the capacitance to around 470ish. Just a thought, not a big deal...
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