Hobbymate Asteroid 3 inch quadcopter: Build Tutorial and betaflight pids etc.

The Hobbymate Asteroid is a new 3 inch quadcopter that is available in kit, BNF or PNF formats that is available with motors and electronics suitable for 4s or 6s (!) operation. Following on from the awesome Hobbymate Comet (built here and reviewed here) this is another premium set of components at a spectacular price. It is available exclusively from HobbyCool.com here:

http://hobbycool.com/asteroid-3-mini-fpv-racing-drone-kit/

The purpose of this blog is to show how I have built in close detail and how I have set up betaflight software for optimal performance. Note you can spend an extra $30 to have this build with a FRSKY receiver but I always like to tinker and optimise my build which is why I have chosen this path. Update: review now completed here

I like to take my time on a build and ensure I have a clean well lit area. Makes things easier when I inevitably drop screws or small parts on the floor. My recommended list of budget tools is here.

1. Overview of all the parts. Components are outstanding, I will cover this more in part 2 (the review)

2. Closer look at the motors. These are more beautiful in real life with a 1 piece bell

3. This Iflight stack is compact, well desined and capable of up to 6s!

4. Lightweight Caddx EOS2 cam. This is the 4:3 version which gives a much better FOV than the 16:9 version as found on the trashcan

5. All frame components can be seen here. 4mm thick arms with sandwich plate design.

6. As you can see from this mockup the frame is a heavily stretched-x

7. Motors mounted to arms using the include m2 screws - 3 per motor. I used this cheap threadlock

8. 4 x m3 12mm screws up from the bottom plate through the arms which butt up against each other.

9. Sandwich plate over the screws from step 8

10. 4 x standoff on next

11. Next attach the EOS2 cam to the carbon side plates. I put a m2 washer between the cam and each side plate in order to stop the camera housing from fouling

12. Here the long m2 stack screws have been installed with the red iflight locknuts securing them. On this went the ESC which was soldered on. Here you can see me test fitting a unique capacitor location

13. Capcitor legs were trimmed to align with battery pad location on ESC and heatshrinked to minimise risk of shorting. I use this pack of various heat shrink

14. Capacitor soldered on. Make careful note of polarity

15. Standoffs replaced- ensure capacitor legs to not expose bare metal to frame or standoffs

16. The loose heatshrink you saw from step 12 is then heated to ensure the capacity or held tightly to the rear standoffs. This capacitor is not going anywhere! I used this skrink tube

17. FC goes on next after the black m2 4mm rubber spacers. Make sure you get the pins square. This is what the default harness looks like for receiver and battery. Yuck! lets tidy it up.

18. I used my trusty FRSKY XM+ receiver and attached the 3 pin connector that mates to the flight controller then heatshrink for safety.

19. This is why I love the EOS 2 - when you twist the rear cover way you can desolder the standard wires and attach your own. Note: never remove both screws or you will expose the sensor

20. Here you can see the stock wires desoldered and the pads exposed. Removing the conformal coating (black) is simple with the soldering iron.

21. My shortened and simplified harness soldered directly to the camera. So tidy now.

22. The 3d printed part that looks like a C&B is a nice antenna mount. Slide the coax cable through as above and cut a short piece of heatsink to fix it together.

23. With heatshrink in place this is rigid and lightweight. I woud recommend the Foxeer Lollipop UFL antenna if you wish to upgrade.

24. Receiver, camera and antenna plug connected from steps 20, 21 and 23 respectively. VTX went on after more 4mm rubber spacers. Again take care of connecter pins

25. Top plate goes on after securing the receiver to the vtx with double sided tape. I use this one. 

26. Receiver antennae come of the arms in a perpindicular manner using cable ties and fasted with heatshrink. These 4 bladed props looks and sound great but have poor top end and high current draw.

27. My real prop of choice - the Gemfan 3052. Pick some up from HobbyCool here when you order the asteroid.

28. Final weight is just under 140g. This is very light for a 3 inch with such powerful motors. It is going to be quick

Betaflight setup
The first thing you will need to do here is update your betaflight configurator to the latest version (10.5.1 for me at time of writing) and then update your flight controller too - 4.0 at time of writing. The target as you can see below is OMNIBUSF4SD. Once I have confirmed board orientation is correct (note: it is as installed above) and motors direction is correct (I prefer props out) then we can customise. For the tune I went with the betaflight community presets as linked below; namely 3" Quad - 14xx-15xx Motors (in coordination with George Hartmann). I found this to be a great start point for PIDs and filters - much better than default which is targeted towards 5 inch.

​https://github.com/betaflight/betaflight/wiki/Community-Presets

Please see screengrabs below for customised setting or grab just use my diff file driectly below for all of my customised settings.

asteroid_4.0_diff_all.txt
File Size:	3 kb
File Type:	txt

Download File

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Ports set up like this. Note: I've confirmed with Iflight that this stack does not support ESC telemmetry

My config settings 1/3. Especially note board alignment (rotated 270°). 8k/8k no issue

I always run airmode, antigravity, dynamic filters.

I now recommend dshot beacon only for aux activated since loosing reception could cause motor burn

Amperage meter scale still needs a little tweaking - will update final value here as a start point

PIDs and settings here suit this quad well. There is some propwash though that could be fine-tune with D values

More PID settings - note TPA and breakpoint

Filters. This is probably more important that the PIDs and based on community presets. Motors stay cool.

My SBUS receiver settings with RSSI transmitted on channel 16 (Aux12)

My personal Aux switches - customise as you like

My personal mode switches to allow rate profile switching on a 3 way and OSD toggle on a 2 way

My OSD settings. Again a personal preference to tune to your liking. Note my camera is NTSC.

Thanks for reading, if you found this article useful please feel free to like or share, the facebook links below directly link/like this article. Links are affiliated and help me buy the bits I need to produce this type of content.

Full review has now been completed here including GPS speed runs on 3s and 4s.