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Xiaomi Repeater onBoard Tello mod

raulvolador

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Hi,

Most of us use a Xiaomi Repeater in ground for improving Tello performance, Have you ever wonder what would happen by using a couple of Xiaomi repeaters ?

First Xiaomi Repeater stays on the ground, close to smartphone, second Xiaomi Repeater its onBoard atached flying Tello. See diagram

lanscape xiaomi onboard.jpg

By the way, I'm not the first one into this mod. I read about it some time ago into @Customerx thread located here: Another mi xiaomi mod. But not what you'd expect... Thanks a lot for your inspiration to @ph2t and @Stele

I decided to build and test this mod by myself. It's an easy and cheap work. Above all it is non-destructive modification, that means your Tello remains inaltered. You can mount/dismount mod over an stock Tello in only a couple of minutes.

Test results were astounding. An impressive improvement into video quality and range. Only drawback its increased weight and therefore decrease in flight time, but Let's go into the how-to and test section.

BUILDING TUTORIAL

First of all you will need to open first Xiaomi Repeater. A bit of brute force needed as no screws presented. Tools used were a knife and a screwdriver. At the end you will get internal pcb, usb wired connector and two plastic case halves (click over every image to view full-size)

xiaomi repeater opening.jpg

Buy an stock USB OTG cable. IMPORTANT ensure it's an OTG model not an stardard USB charging cable.

usb otg cable.jpg

Cut USB OTG cable and stay microUSB piece, throwing away USB piece. Solder about 15 cm parallel cable into red/black power lines.

cable welding.jpg

Replace existing Xiaomi power wires by soldering new cables into board pads. Polarity +/- is printed into pcb.

cable and xiaomi.jpg

Test your work pluging in microUSB connector into Tello, switch Tello on and verify Xiaomi blue LED light is on.

first test.jpg

Use a piece of heat shrink tube for covering Xiaomi Repeater Board and cable weldings. Try to let a little hole for accesing Xiaomi reset button if needed.

heat shrink tube.jpg

Remove Tello's white top cover. No tools needed, use your own nails.

top case.jpg

Use a couple of 20 centimeters cable ties for fixing Xiaomi Board on top Tello. As Tello's top is not totally flat put a little piece of foam for best adjustment. DON'T TIE TOO MUCH or you can warp Tello's frame. I recommend you working when battery pack inside.

cable ties.jpg

This is final result, a bit Frankestein style, but it works.

xiaomi onboard finished.jpg

I have to split so long text, please see next post for test results...
 
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raulvolador

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PREFLIGHT CHEKS

Power on Tello and using free Android MI app connect your onboard Xiaomi repeater to Tello. It will be shown into your smartphone available Wifi screen as TELLO_plus. Power on ground Xiaomi repeater and connect it to Xiaomi onBoard. It will be shown as TELLO_plus_plus, that's the network you should connect for flight.

Before flight make sure there is enough room for propellers to turn freely !

xiaomi onboard side view.jpg

Be aware WIFI power level meter will not work anymore. It will always show 90db maximun power becouse Tello and onBoard Xiami are close together. Use instead new bitrate measure. You should activate it by checking 'show corruption indicator' into TelloFPV video settings.

bitrate meter.jpg

TEST RESULTS

Mod results are amazing. I noticed an stronger signal and a much better video image. All of my test were performed using TelloFPV app into a residential area, full of neighbor WIFI networks. I could fly at full 4mb/s bitrate up to 50 meters away, 3mb/s up 100 meters away and 2mb/s 150 meters away. Best of all I can freely turn or perform aggresive movements no afraid of loosing connection. Range at 1 Mb/s improved a lot. I flew a well-know route and got an amazing 323 meters range. Previous flight single Xiaomi Repeater same place and conditions I only got 128 meters. That's an incredible x2.5 range improvement.

Here: 128 meters range single Xiaomi Repeater on ground:
test no onboard 128.jpg
Here: 323 meters improved x2.5 range using onBoard second Xiaomi Repeater. Notice 90db max reading despite low signal. Small red box on top of image it's same area than previous test.
tes xiaomi onboard 323.jpg

Major drawback this mod is decreasing flight time about 20%. I can fly 8 minutes landing at 10% battery level, or 7 minutes landing at 20% battery remaining.

I suppose motors suffer wear and overheating due increased weight and their lifespam will decrease too.

I suggest you trying this mod. It's easy and cheap. Maybe too bulky and fragile to become permanent, but great for doing it sometimes. I hope it helps.

Raul.
 
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dood

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Great stuff! I was thinking to try something like that, but instead of using that repeater maybe I'll just buy an repeater with larger antenna and use LEGO mount to hold it.
 
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Customerx

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Excellent to see the results :)

Have self contained the Xiaomi mi and a battery system now. So it doesn't draw on the TELLO battery. It uses two cr2032 batteries in parallel giving 6v which the mi is happy with. Have tried the lir2032 but the mah are lower. Still an additional mod with the Lego attachment. Doesn't affect the TELLO too much. Better weight including batteries shown below. Self contained switch. Works well.
 

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Customerx

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This is the DIY CR2032 3V Button Coin Cell Battery Holder Case Box With On-Off Switch Screenshot_20190402-131526.png

then just solder the positive and negative direct to the Xiaomi.
 

raulvolador

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Good idea, but I'm afraid the biggest problem its the increase in weight. Battery drain by Xiaomi Repetar should not be too great. Anyway I will wait for your flight tests
 
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Customerx

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I've tried additional batteries of all shapes and sizes, different combinations of voltages and mah, this was the best compromise. It reduces all the additional cable etc. I was very impressed with the thoroughness of your tests by the way. Well done Raul.
 

Jdub

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Nice I'ma try to connect my dlink 1600 extender I made wireless when I lost my old xiaomi after I connect my new one to tello. Like all the details dude can't believe I didn't think of it before thanks... Also I attached my tello to a Vivitar Aeroview that has GPS but hashas terrible video with extender... worked good here's the picture and here's a link to the video
IMG_20190327_175000781_HDR.jpgIMG_20190327_175000781_HDR.jpg
 
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raulvolador

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Nice I'ma try to connect my dlink 1600 extender I made wireless when I lost my old xiaomi after I connect my new one to tello. Like all the details dude can't believe I didn't think of it before thanks... Also I attached my tello to a Vivitar Aeroview that has GPS but hashas terrible video with extender... worked good here's the picture and here's a link to the video
@Jdub ,

Please, help me keeping this thread focused into Xiaomi onBoard mod. Please, open a separate discussion for your dlink 1600 extender attemp.

Thanks a lot.

Raul.
 

raulvolador

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Hi all,

I did another four flights using OnBoard Xiaomi mod. I'm really surprised how Tello 's performace improved.

It's not only a matter of range, I feel much more confident flying close distances too. Before Xiaomi onBoard mod I suffered many lost of image when performing quick turns. It doesn't happen anymore. I used to fly at lower Bitrate (1Mb/s) for safety. Now I fly up to 4 Mb/s for best quality images. Shooting photos from long distances was a hell as it took long time or was cancelled. Now I can shoot photos without worrying.

All of my test flights were performed in well-know places, so I can compare performance change.

As an example, this screenshoot 172 meters away into residential area, flying at full 2Mb/s. Same place some days ago I only got about 120 meters at half bitrate 1Mb/s (without Xiaomi onBoard mod)

172 A 2MB.jpg

I'm afraid it will cost me a lot to get rid of this mod...

Raul
 
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Guorium

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Hi all,

I did another four flights using OnBoard Xiaomi mod. I'm really surprised how Tello 's performace improved.

It's not only a matter of range, I feel much more confident flying close distances too. Before Xiaomi onBoard mod I suffered many lost of image when performing quick turns. It doesn't happen anymore. I used to fly at lower Bitrate (1Mb/s) for safety. Now I fly up to 4 Mb/s for best quality images. Shooting photos from long distances were a hell as it took long time or was cancelled. Now I can shoot photos without worrying.

All of my test flights were performed in well-know places, so I can compare performance change.

As an example, this screenshoot 172 meters away at residential area, flying at full 2Mb/s. Same place some days ago I only got about 120 meters at half bitrate 1Mb/s (without Xiaomi onBoard mod)

View attachment 3664

I'm afraid it will cost me a lot to get rid of this mod...

Raul
hows the latency
 

raulvolador

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hows the latency
That's a very good question. I suppose latency should increase a bit, as signal has to be routed throught second Xiaomi Extender. Anyway I didn't notice any problem due latency during my flights. I'll try to measure it and will report here.

Raul.
 
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Customerx

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So pleased with your tests Raul, had quite a few doubters on this mod. Glad to see that I hadn't wasted my time coming up with this. Credit to you Raul for doing the tests. :)
 

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