MOBULA7 UPGRADE: Betaflight 4, PIDS and Filters

The Happymodel Mobula7 uses a F3 based flight controller and since Betaflight 3.4, these boards have not had full functionality of F4 and F7 boards due to smaller memory size for firmware storage. However in this article I will cover how to upgrade to the performance edition of Betaflight 4.04 kindly compiled by UAVTech (his in depth YouTube Channel is here). This special version adds the key performance functions at the cost of typically irrelevant features like servo control, acro trainer, camera control etc. In this article I will show you where to access this firmware and then I'll show you the filters that suit brushless whoops best as well as some good starting PIDs. 

This is the seventh and likely final article in my series of HappyModel Mobula7 upgrades, many of which can be used for the Trashcan too. Also to come are:

• Swapping to a much more durable frame​
• Improving the battery connector for more power
• converting to run 'props out' 
• Long term propeller upgrade recommendations​
• Converting your 1s batteries into a true 2s battery
• receiver range improvement​

All links will be updated here when completed. Many of these I've completed the work and am testing at present - it's starting to feel like a more complete little quad now. If you're looking for my review of the mobula7 including setup it can be found here

Betaflight 4 Performance edition for F3 boards
This is the final version of Betaflight you can use and I strongly recommend you use this version rather than the one on the Betaflight configurator to get full performance functionality otherwise you will miss out on features like:

• Gyro Lowpass2
• Launch Control (optional - OFF by default)
• Dynamic Lowpass Filters (Dyn_LPF) (ON by default)
• D-term Minimum (D_min) (ON by default)
• Throttle Boost (ON by default)
• iTerm Relax (ON by default)
• RC Smoothing - Filter (ON by default)
• TPA Mode - D-term ONLY option (ON by default)

Download the custom file below at the GITHUB source. SKIP THIS STEP FOR THE EACHINE TRASHCAN

For FRSKY built-in receiver

betaflight_4.0.4_crazybeef3fr_performance.hex
File Size:	679 kb
File Type:	hex

Download File

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For Flysky built-in receiver

betaflight_4.0.4_crazybeef3fs_performance.hex
File Size:	646 kb
File Type:	hex

Download File

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Filter setup
I'll keep this simple and will recommend the community preset for 'brushless' whoop (credit again to UAV Tech). Filters are customised to the higher RPM (hence frequency that these small motors run and resonate at. This is more important than the PIDs Copy/paste below into your CLI:

set gyro_lowpass_type = PT1
set dyn_notch_min_hz = 150
set dyn_lpf_gyro_min_hz = 150
set dyn_lpf_gyro_max_hz = 750
set dyn_lpf_dterm_min_hz = 150
set dyn_lpf_dterm_max_hz = 250
set dterm_lowpass_type = BiQUAD
set dterm_lowpass2_hz = 0

Alternatively you can enter into the Betaflight GUI as per the screenshot below. Note: I recommend these settings for all brushless whoops including the Mobula7, Eachine Trashcan, Emax Tinyhawk etc.

Recommended PIDs
I've seen no need to change the PIDs that are also recommended in the community presets. Once oscillations are taken care of PIDs are more of a 'feel' thing. I've been happy with these PIDs, they are certainly better for me than default:

set vbat_pid_gain = ON
set anti_gravity_gain = 5000
set p_pitch = 33
set i_pitch = 85
set d_pitch = 35
set p_roll = 28
set i_roll = 78
set d_roll = 32
set d_min_pitch = 18
set d_min_roll = 16
set d_min_boost_gain = 30
set d_min_advance = 0

And again with the screenshot if you'd prefer (click to embiggen):

My Diff All

If you want to use or review betaflight exactly as I run it on my own Mobula7, I have attached my "Diff All" file below:

quadifyrc_mob7_beta_4.04_performance_diff_all.txt
File Size:	2 kb
File Type:	txt

Download File

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Summary of software improvements
Wow. Not since I've flown my NFE silverware brushed whoop have I enjoyed so much control. I'm not a great pilot but even flying at night in poor lighting conditions I felt fast and largely in control. Flight was predictable and I was able to put the quad where I wanted practically all of the time. Below is a DVR of me flying at night in my backyard. There's no wind which is a welcome relief. This flight was done with a 75% throttle limit on a 2s 300mah battery and low rates (about 300 deg/s max on yaw, pitch, roll). I hope you enjoy these settings as much as I do.

And this will round out my series of Mobula7 upgrades. It's been fun tinkering with this very popular brushless quad for the last few months and these software settings finally connect all the hardware improvements and customisations I've made over this series. Click here to see all of them

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. If you are looking for quads or parts check out my coupons and discounts page which I keep updated with only the parts and quads I like at a proper discount.

​My favourite parts for the mobula7/trashcan:

Propellers: Gemfan 1635 These props have stood the test of time and are still the best in 2020. Consider the 4 bladed 1636 if you want more control

Frame: Mobula7 V2. I prefer the performance of this frame over the v3 and it is stronger than the V1

Batteries: GNB 2s 300mah are simply the best batteries for this quad. 4 pack is great value or buy indivually here

Battery holder: Rubber band These are the perfect size for your mobula7. 

Happymodel XT30 Plug Pigtail If you want to go to XT30, this cable includes a capacitor and is very cheap

Happymodel EX1102 Brushless Motor Larger 1102 sized motors that will fit your mobula7 that will give you better power and speed. I'd recommend 13500kv and a 1mm shaft for the mobula 7. Standard 0802 replacement motors are here

$2 E6000 glue. This glue has some flex and is perfect for plastic frames. Think of it like am improved hot melt glue. Make sure you have some in your tool box.

FRSKY XM receiver. If you can't handle the barely adequate range of the SPI receiver, this supersmall receiver will greatly reduce your range on FRSKY