• Requested: iNav CLI dump

    Because I've received few requests to share iNav configuration that allowed performance like showed here and here, below you can find most important parts of my configuration. I've removed some parts like AUX, serial configuration, MAG and ACC calibration. They are mostly iNav defaults, no special tweaking was made. I hope this will help.

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  • iNav: Waypoint Mission

    This video was taken few weeks ago during my tests of Waypoint Mission implemented in iNav.

    Hardware setup:

    • Transporter Q7.6 600mm quadcopter frame
    • SPRacingF3 Acro with BMP085 external barometer
    • Beitian BN-880 (ublox Neo-M8M)
    • 10x4.5" APC props
    • EMAX GT2218/08 1100KV motors
    • 5000mAh 3S battery

    Software setup:

    • iNav pre 1.1
    • Default navigation PIDs
    • Slightly tuned FP-PID, quite close to default values
    • GPS nav model: HIGH_G set gps_nav_model=HIGH_G
    • Velocity calculation done by GPS module set inav_use_gps_velned=ON

    Mission plan:

    1. Take off in Angle model
    2. Follow 3 waypoints on total distance of about 300m, constant altitude of 10m
    3. At last waypoint goto Position Hold mode
    4. Manually engage Return To Home mode
    5. Automatic RTH and land

    Read more...
  • Improving cheap radio range

    Radio range of my first drone, UDI 829A was pretty pathetic. OK, it was (still is, I only have to finally replace motors) pretty indestructible, quite stable and reasonably priced. But effective radio range as quite short. More less 50 meters. Above that limit strange things started to happen. The reason was pretty simple. Just take a look at this picture.

    Antenna too short

    Can you see the transmitter antenna? Yeap, that it this short cable. Not only it does not go into "antenna cover" of the receiver, it is also horizontally polarized and when receiver is held in a normal way, pointing into a drone, it emits almost no signal in this direction. This and an additional single whip antenna on the receiver makes it virtually impossible to have a good radio range.

    So, I've decided to fix that and install external antenna that would work with vertical linear polarization and actually emits some power in drone's direction.
    This tutorial shows how to do it for UDI 829A, but will work almost all cheap drones. Their transmitters are very similar inside and as long as there is antenna pad or connector, it can be done. Read more...

  • iNav: RTH with land mission

    This video was taken last weekend during tests of latest changes implemented in iNav, as well as new GPS module Beitian BN-880 I shortly described here.
    Mission plan:

    • Take off in Angle mode,
    • Engage 3D Position Hold
    • Fly away 100m
    • Return to Position Hold
    • Engage Return To Home mode

    Summary:

    • Beitian BN-880 performed well. Quadcopter returned home with 1m accuracy. Constant fix on 15 sats all the time and HDOP at 1.2
    • No problems with magnetometer inside GPS module
    • No bigger problems during whole mission. I still have to work on yaw behavior. At the moment FP-PID and linear mixer from Betaflight can cause some strange yaw behavior on bigger quads. Fix should be available soon
    Read more...
  • Battery C rate: do I need a lot of it?

    One of the values that describe LiPo batteries used in RC crafts is so called C rating. For example: 3S 1300mAh 45-90C. Or 3S 5000mAh 25-30C. Or 4S 1300mAh 65-95C. S is simple, it tells the voltage. mAh or Ah tell capacity.

    But what about C rate? According to Wikipedia is can be described as:

    The C-rate is a measure of the rate at which a battery is being discharged. It is defined as the discharge current divided by the theoretical current draw under which the battery would deliver its nominal rated capacity in one hour. A 1C discharge rate would deliver the battery's rated capacity in 1 hour. A 2C discharge rate means it will discharge twice as fast (30 minutes). A 1C discharge rate on a 1.6 Ah battery means a discharge current of 1.6 A. A 2C rate would mean a discharge current of 3.2 A.

    So, if we take a look at Turnigy Nano-tech 3S 1300mAh 45-90C we will know that:

    • Constant discharge current on 45C is 58.5A
    • Burst discharge current (10 seconds) on 90C is 117A

    Neat, yeah? Almost 60A constant current! That gives 15A per motor. And that a lot on 250 or smaller quad. So, I should be fine! Read more...

  • Hands-on: Turnigy Graphene LiPo batteries

    LiPo battery life is hard. Charged, discharged, beaten in a crash, charged, discharged and so on. Because last week I had to utilize few of my old Turnigy Nano-tech LiPos, I've decided to try something "better" this time. Turnigy Graphene 1300mAh 3S 65C. Package came today and this is what I got:

    Turnigy Graphene LiPo in box

    Turnigy Graphene LiPo there is even a bag inside

    Turnigy Graphene LiPo Battery

    Turnigy Graphene LiPo

    • Box is huge. Really, it would fit 3 LiPos, not just one. Kind of waste. But box is nice enough to reuse for something else
    • Black is the color of choice here. Black and red. I like this combination
    • They are noticeably heavier than 1300mAh 3S Nano-tech LiPos. But they have 20C more, so that was predictable

    More after the weekend when I should be able to give them a first try.

    Read more...
  • Magical LiPo tree

    Magical LiPo tree

    Since LiPo batteries are potentially dangerous, they can not be just put into garbage. They have to be properly handled, utilized, before they can be safely thrown out. I will write more on this topic later. Here is only a picture of my magical LiPo tree. Knife, electrical connector, 12V halogen lightbulb, some sand, a flowerpot and LiPo discharger ready.

    Read more...
  • Hands-on: Beitian BN-880 GPS module

    Looking for a decent replacement for my u-blox NEO-6M GPS modules I came by super cheap, Chinese, Beitian BN-880 modules from Banggood. According to information found in the internet, it's build based on u-blox Neo-M8N and is capable of receiving signals from GPS, GLONASS, Galileo, BeiDou, QZSS and SBAS. Plus integrated magnetometer module. Yesterday package finally arrived and here are my first impressions:

    • It's not single board, but 2 boards glued together
    • There is not casing, and cases for popular Neo-6M wont fit. BN-800 is much taller
    • It accepts both 5V and 3.3V voltage and 5V UART level is safe, nothing burned
    • It connected to Cleanflight and iNav without any problems at 38400bps
    • Quick windowsill test showed that indeed it works not only with GPS, but also other positioning systems. When GPS Neo-6M was barely able to acquire 4 satellites, Beitian BN-880 found 9 and a solid 3D fix
    • I did not tested magnetometer yet

    Beitian BN-880

    Beitian BN-880 Antenna

    Beitian BN-880 Side view

    Hopefully I will be able to perform more tests next few weekends and provide more info on this module. For now it looks very promising.

    Read more...
  • iNav: Return To Home with land

    New release of iNav is at the doors. Today I took testing version for a spin and tried few navigation scenarios. For example, transition for Position Hold to Return To Home with landing. It looked like this:

    It behaved fantastically: nice accuracy, precise landing. There were few wobbles on descend, but that was caused not yet tuned FP-PID of Angle mode and hard flying conditions: gusty wind up to 15m/s.

    Read more...
  • Happy Multirotor Easter

    dav

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Paweł Spychalski

I'm Paweł Spychalski and I do things. Mainly software development, FPV drones and amateur cinematography. Here are my YouTube channels: