#Microlongrange OpenHD Edition

Hello All :slight_smile:

I made a remix of dave_c‘s awesome #Microlongrange project.

My goal was to create a quadcopter with 10km+ video range while still being able to fly below 250g starting weight for legal reasons.

I used the following hardware:

Flywoo Explorer Frame 4“
Matek F722 mini SE flight Controllers
Diatone Mamba F30 HV
TPlink T4U V1 wifi Card
Pi Zero 1.3
Arducam imx477 mini camera
BN220 GPS
5883 Magnetometer

Battery: 4S 850mhA liPo to stay below 250g
Or:
4S 18650 LiIon for maximum flight time ( of up to 38min.)

Here are all the 3D printed parts you will need to put it all togheter

And get an assortment of M2 screws with a flat head. The longest you will need is 16mm.

And some pictures from during and after assembly:

5 Likes

Nice build! Pleas share your range results when you maiden- Good luck!

Thank you Luke :slight_smile:

I already did the maiden and it flys good on iNav default PID‘s.
Needs some tuning arround the yaw axis thought.
Afterwards I tested it’s freestyle ability’s and shattered the cameras IR filter… so this needs replacement.
I will do the Range testing afterwards, but judging the signal strength I saw until now, I think the battery will be the limiting factor, not the video link. But we will see.

Sounds really good!

I am playing with TPlink T4U V1 at the moment, but only getting maybe 150 meters of range. If you getting better results please share more details about your hardware and software setup.
Did you solder circular polarized antenna directly to card? Also, only one antenna is sticking out. Where is the second one?

Ah yes thanks for pointing out.
I soldered the RHCP antenna which came with the flywoo frame kit to the WiFi card. The second antenna is disabled in default settings, but I have it connected to the internal antenna to protect the amplifier if activated.

2 Likes

could you tell which settings define that? I did some signal strength tests with antenna connected to each port, and it looks to me that both antenna ports are active in my setup. Most of settings are default thought.

Yes:

UseMCS=N
UseSTBC=N
UseLDPC=N

All of them =Y uses 2 antennas.
one of these or a combination of some could also do, Not sure exactly.

Could you specify your test setup?

Well, this is good question, because I have some doubts about my test too.
I use 1.5 meter antenna extension cable. I have an IP-9 connector adapter, so I can connect antenna to any port. Air and Ground sits about 1 meter apart. I connect one of Air antennas via extension cable and bring that antenna closer to Ground antennas. Signal strength (checking dbm indicator) increases significantly. And it acts the same, does not matter to which antenna port I connect that extension.
Is that because I bring ground (electrical ground) of that extended antenna closer and that is enough to increase signal strength even if that antenna isn’t active? And therefore my test is invalid?

I did same test with
UseMCS=N
UseSTBC=N
UseLDPC=N

and
UseMCS=N
UseSTBC=Y
UseLDPC=Y

and I got same results.

I don’t know im sorry.

Well that is fine. I am looking for answer how those dual antennas works for a while without success. I just wouldn’t be so sure that that 2nd antenna is disabled, but as long as it is connected to PCB, it shouldn’t be a problem.
Please update us once you have range report of your setup. I am really interested in that as I am using similar hardware on Air.

I think that is the correct link…

2 Likes

I am wondering how openhd works for you on these micro drones. I mean how latency affects the experience.
My openhd based system gives me 115ms latency, but for calm flying on stabilized fixed wing is not a problem for sure. But what about these drones? Are you limited to cruising only? Or such latency is fine also for some more aggresive maneouvers?

It’s fine for chill flying and a loop or two. But for aggressive manovers it’s not suitable imho. This small copter can do a whole flip in these 115ms :sweat_smile:

UPDATE

I found that this high quality camera is not a good companion for the Pi0 so I upgraded it to a „Pi3 mini“ which is actually a part of HTC VR googles modified with an additional camera connector. Runs OpenHD very well and out of the box.

Last flight was made with 1080/40fps and ~8MB/sec. It’s beautiful :slight_smile:

Also my first antenna + Gps holder is too fragile and I switched to the stock antenna and a new GPS holder.
Smaller beeper.

More planned updates are:
uFL antenna connectors for better serviceability.
A better (longer) antenna to ease the GPS interference as it’s not as good as I like it to be… If this won’t help I will switch to a better GPS module.

1 Like

I’m following with great interest. Where do you find this “Pi3 mini” board? I’m not coming up with anything in my searches with any of the board model names and numbers I see on your photos. Thanks,

I ordered it here through „yoybuy“ buyer agent. But be aware, some other people had problems with this seller on Taobao as it’s out of stock suddenly, and maybe lost their Money.

https://m.intl.taobao.com/detail/detail.html?id=630406027686

Can be found inside „ TPCAST HTC VIVE Wireless Adapter“

image

After some more tuning I am happy with all the settings now. Here is my iNav diff:

diff

version

INAV/MATEKF722MINI 2.6.1 Feb 25 2021 / 10:53:27 (64249b1a)

GCC-9.2.1 20191025 (release) [ARM/arm-9-branch revision 277599]

start the command batch

batch start

mixer

mmix reset

mmix 0 1.000 -1.000 -0.659 1.000

mmix 1 1.000 -0.809 0.659 -1.000

mmix 2 1.000 1.000 -0.659 -1.000

mmix 3 1.000 0.809 0.659 1.000

feature

feature -BLACKBOX

feature -OSD

feature GPS

feature PWM_OUTPUT_ENABLE

serial

serial 0 2 115200 115200 0 115200

serial 3 256 115200 115200 115200 115200

aux

aux 0 0 0 1300 2100

aux 1 1 1 900 1675

aux 2 2 1 1650 1750

aux 3 3 1 900 1650

aux 4 11 1 900 1350

aux 5 10 1 900 1250

aux 6 13 2 1300 2100

master

set looptime = 500

set gyro_hardware_lpf = 256HZ

set gyro_lpf_hz = 110

set gyro_lpf_type = PT1

set gyro_stage2_lowpass_hz = 250

set gyro_stage2_lowpass_type = PT1

set dynamic_gyro_notch_enabled = ON

set dynamic_gyro_notch_q = 200

set acc_hardware = MPU6000

set acczero_x = 99

set acczero_y = -11

set acczero_z = -338

set accgain_x = 4074

set accgain_y = 4105

set accgain_z = 4031

set align_mag = CW270FLIP

set mag_hardware = QMC5883

set magzero_x = 690

set magzero_y = 110

set magzero_z = 125

set maggain_x = 1215

set maggain_y = 1317

set maggain_z = 1303

set baro_hardware = DPS310

set pitot_hardware = NONE

set min_check = 1050

set rssi_channel = 16

set serialrx_provider = FPORT

set serialrx_inverted = ON

set blackbox_rate_denom = 8

set motor_pwm_protocol = DSHOT600

set throttle_idle = 12.000

set failsafe_procedure = RTH

set failsafe_min_distance = 2000

set failsafe_min_distance_procedure = SET-THR

set align_board_roll = -8

set align_board_pitch = 14

set bat_voltage_src = SAG_COMP

set motor_direction_inverted = ON

set model_preview_type = 3

set disarm_kill_switch = OFF

set applied_defaults = 2

set gps_sbas_mode = AUTO

set gps_ublox_use_galileo = ON

set mc_airmode_type = THROTTLE_THRESHOLD

set nav_mc_hover_thr = 1400

set i2c_speed = 800KHZ

profile

profile 1

set mc_p_pitch = 50

set mc_i_pitch = 60

set mc_d_pitch = 25

set mc_p_roll = 45

set mc_i_roll = 50

set mc_p_yaw = 50

set mc_i_yaw = 70

set max_angle_inclination_rll = 400

set max_angle_inclination_pit = 350

set dterm_lpf_hz = 91

set dterm_lpf_type = PT1

set dterm_lpf2_hz = 150

set dterm_lpf2_type = PT1

set yaw_lpf_hz = 30

set d_boost_factor = 1.500

set antigravity_gain = 2.000

set antigravity_accelerator = 5.000

set setpoint_kalman_enabled = ON

set setpoint_kalman_q = 200

set thr_mid = 45

set thr_expo = 60

set rc_yaw_expo = 70

set roll_rate = 70

set pitch_rate = 70

set yaw_rate = 60

battery_profile

battery_profile 1

set bat_cells = 4

set vbat_min_cell_voltage = 300

set vbat_warning_cell_voltage = 320

set battery_capacity = 3000

set battery_capacity_warning = 750

set battery_capacity_critical = 600

uFL antenna connectors for better serviceability.

Are you planing to solder uFL connectors on pad of original test connector (IP9)? I was thinking about that too as lighter replacement for SMA pigtails, but I decided to go with MMCX female pigtails and securely fix those MMCX somewhere on cards bracket. Something like on DJI VTX.

Yes exactly.
I ordered some to play arround with, should be here this week.