A quick article here to stop the beeping of your battery alarm on punch outs all the time - especially micros where you tend to get a reasonable amount of battery sag. The battery voltage monitor on betaflight is probably one of the key pieces of information conveyed by the OSD or buzzer but is really annoying when it goes off all the time on punch outs when the battery immediately recovers afterwards. That's because the flight controller samples the battery voltage very frequently and will report on even the most minor dips below set value (0.1V by default).
A really useful tool is to use vbat_hysteresis in the CLI section of betaflight. By default vbat_hysteresis is set 1, which is 0.1V (i.e. alarms if 0.1V less than warning/critical values that you set). I found that by setting this value 3 (i.e. 0.3v) I didn't have the unneccessary warning on punchouts now did I have to compromise the actual settings I like my warning and critical values set at - 3.5 and 3.3V for the record.
For those have not use the CLI in betaflight yet, simply go to CLI on the bottom tab in betaflight configurator. Type "set vbat_hysteresis = 3" <Enter> "save" <enter>, Job done! If you want to revert to default, use "set vbat_hysteresis = 1" <enter> "save" <enter>
The Fly Egg 100 and 130 are 2 popular micro quads although like many other micros they have only have a cheap CMOS camera for FPV. The Swift and Arrow micros have been simply fantastic as an upgrade for micros like the leader 120 and I've covered that upgrade recently for that model.
It's much harder with the fly egg series though because there is only 15mm between the sideplates of the frame where the camera sits which is too narrow for the width of 19mm micro cameras. Modding is near impossible because the frame cannot be drilled for a wider mount and it is too far for the side plates to stretch to accomodate.
Now there is a new solution. King Kong have just released the FPV Egg 136 which is 4mm wider to allow for the micro swift. Although the complete frame is available for $23, I believe you can just get away with purchasing the new 136mm bottom plate only for $8.63 (less than $8 if you use the code "toysho"). This way you can recycle most of the parts from your fly egg 130 or 100. There are some caveats however.
Considering how compex the previous solutions were though, this will be a breeze or you could just take the path of getting the new frame with all the correct hardware. The good news is that since the fly egg comes with a good variable power VTX that is not piggy-backed to the CMOS, it will easy to re-use with the new camera. Also good is that the Micro Swift 2 and Foxeer Arrow 2 have a basic VBAT OSD and this will be a huge improvement to the OSD-less fly egg 100/130.
I have a new 136mm bottom plate on order and will update here when I've mounted the micro swift 2.
Here are the parts I've discussed in the article, click on the image to take you to the product:
The Leader 120 is my favourite micro quad but manufacturing to a price point has meant that although not uncommon, the camera and VTX leaves something to be desired. I found that although it handles light well for an AIO camera, it is poor compared to a CCD camera meaning flying in an out of dark areas can be challenging. Additionally the VTX is limited to 25mW so total distance before video breakup is not fantastic, especially around trees or other obstacles.
I used a micro CCD camera (in this case the camera from the HGLRC XJB F428 Elf) and the new Full Speed TX200 VTX as a way to replace the AIO camera/VTX supplied as standard. A full review of this setup is here so that I can use this blog to give details of the install specific to the Leader 120. Update: Gearbest sell a clone of the micro swift which is identical to the HGLRC Elf - the Furibee 1672. This performs just the same as the other micro CCD cameras - micro swift, arrow, HGLRC elf. Update 2018: The foxeer micro arrow pro is now the best value and performance micro CCD camera at around $20
For my first attempt at the install please see the captioned pictures below:
Unfortunately with this setup I had digonal lines in the video feed that were made worse when the quad was armed with increasing breakup when throttle was increased. Since this VTX will happily accept 5-17v I supplied power from VBAT rather than using the 5v BEC circuit on the flight controller. This immediately fixed the issue for the minor inconviniece of having to solder additional wires to the VBAT pads. This did however offer the advantage of less stress on the BEC circuit and less risk of brownouts as a result, especially when running on 200mW transmitting power.
You can read my conclusion in the review but to summarise a micro CCD is a must have on the Leader 120. Having to use Vbat due to noise on the flight controller 5v circuit is a minor inconvience but the improvement on signal compared to the AIO camera, even on 25mW is really impressive and running on 200mW opens a whole lot more flying opportunites with much better penetration though trees for example. The additional depth the VTX adds to the camera (meaning the top standoff cannot be fitted) is mildly annoying for the leader 120 but realistic. I thought it would be hard to top the Eachine VTX03 but the tidyness in piggybacking to the camera and ability to do it's own 5v regulation wins it for the TX200.
Update 2018: I forgot to mention this does rely on being held in by wedging the camera between the sideplates but since then I've found a better free solution below:
I trimmed a standoff by approximately 5mm and used longer screws to torque the frame together. This is much stronger and more secure than my previous install. Note: the caddx cameras are a different shape and you may be able to install without trimming that standoff
On my lightweight x2 EYAS (updated build link here) build I use an Eachine TX01 All In One (AIO) Camera/VTX. Stock, these come with a basic Circular Polarised (CP) antenna that works well but is heavy and more importantly: not very durable. This is because the antennas are left fairly exposed on micro quads.
More often now, AIO camera/VTX modules have linnear whip antennas that are much more durable, lighter and still get you about 90% of the performance of the CP antenna - much more practical in the real world for micro. Linnear whip antennas are actually a sleeved dipole where the outside sheild of the co-axial cable is grounded. The exposed centre transmitting signal is then exposed for a VERY specific length that should be tuned to 5.8GHz which in most cases is 12.9mm for a 1/4 wavelength of 5.8GHz.
Albert Kim did an excellent video here and found that most whip antennas have the wrong length. Great! Easy to cut if they are too long, hard to fix if they were too short. Well the 10 spares I had were too short!!
To fix this I tried the trick that my flysky FS82 and RX2a pro receivers use - a basic monopole antenna. This is a simple 28AWG wire (or any other small gauge wire) soldered directly to the signal line of the VTX with nothing on the ground pad. The wire is then cut to precisely 12.9mm, then heat shrunk over the top to relieve stress from the joint. Result:
What I see now is that the main reason for a dipole whip is to elevate the signal out of the frame where the AIO camera/vtx is enclosed. However, when the camera is mounted high like on my EYAS X2, it does not give any benefit and so the ghetto monopole antenna works just as well.
Quick follow up 10 months later and this continues to work well. I've now done the conversion to 4 AIO cameras with no ill effects. I've even done this on a FullSpeed tx200 piggyback vtx (review here) that is attached to the back of a runcam swift and no longer snag and lose the dipole. A really useful mod that has stood the test of time
I've tried all sorts of methods to stop my battery sliding around, especially on micro quads where we are limited to particularly crap battery straps like this. Velcro or even duralock was the defacto standard but maintaining these for every battery can be a pain in the arse (IMO) and they wear out. I've found a great (and inexpensive) alternative - the horribly named Honana HN-CH014 Sticky Gel Cell Pad Anti Slip Phone Pads Kitchen Bathroom House Car Holder
This is a soft gel-like plastic that does not use adhesive tape to stick but it's own tackiness. It leaves no residue and wiping with a damp cloth completely "resets" it to it's original tackiness. This is very similar to the pad that Joshua Bardwell discusses here (kyosho zeal vibration absorption) but this kyosho product is approximately $US13 whereas the one mentioned here is around $US2 at the time of writing. Check out the pics below to see how well it works.
As you can see on the picture at the left, it's easy enough to cut small pieces off as you don't need a lot to do the job and can keep the weight to a minimum. You'll still need a strap or band to hold the battery against it but since I started using this I've had no battery ejections. Not exciting but useful I thought.
Check out this cheap non-slip battery pad for yourself.
The Leader 120 is a very well thought out and put together micro quadcopter that I have reviewed on the bench here and after initial flights here. Flight time is good, especially compared to the quads with the smaller 2" blades. The standard King Kong 2840 3 blade props are strong and well balanced but also fairly agressive that can cause weaker batteries to sag on punch outs.
Since this quad has a lot of blade area for a light weight, I tried the twin blade Gemfan 3025 propellers that have one less blade and a more gentle pitch. Unfortunately the just fould on the frame so had to be trimmed by about 1-2mm to fit. For this job I 3d printed the flexRC jig from thingiverse which can also be bought directly from flexRC. To this you mount a standard nail clipper and can gaurantee the props will be even and balance.
So how do they fly? Excellent. They are slightly louder since they are now essentially bull-nosed but they were well balanced with similar performance to the 2840s although slightly less floaty. Nominal diameter is about 74mm compared to 70mm on the 2840s. But wow the efficiency! On a turnigy 2s 25c 950mah I got over 10 minutes of flight. On a 460mah 3s that is not is good shape I got 4.5minutes of hard flying. Battery sag was MUCH less and the roll dip that occured on a 3s punch out due to the ESC not keeping up was gone! I have a large pack of the 2840s to use up but am thinking of shelving them for the 3025 props. They seem less durable but have still not broken one after about 6 packs - some minor chips only that doesn't seem to have affected performance.
I'm amazed that more performance can be wrung out of this very good micro quad so I'll keep fixing it until it is broken!
The gemfan 3025 props can be purchased here
The KK 2840 stock props (still good) can be purchased here
The Leader 120 can be purchased here (use code HarvestRCnew7 to get this for $US93.99 until end September 2017)
Please comment here if you want to see flight times with the stock battery which has been given a new life!
Problem: a standard FC/ESC stack is too tall and heavy.
A 20 mm x 20mm 4 in 1 ESC and flight controller is the backbone of most micro quadcopter builds. They are usually joined together by m2 nylon standoffs in the middle and bottom that are about 6mm tall each. This can be too high for some builds but there is an easy fix that can even include some basic softmounts. Here are the parts you'll need. They are not expensive and can be used for several builds:
To make the low profile soft mounted stack:
Voila! now you have a low profile stack that is lighter and soft-mounted. After a big crash recently I find it is much stronger too as it relies on the tension of nylon rather than shear.