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Homemade table tennis robot with Android bluetooth control
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Author:  vedroitt [ 17 Mar 2018, 01:30 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Hi all!
I haven't written long time, but the development wasn't stopped.
I worked hard last months with next robot's iteration. The new robot has 3 wheels with auto reverse and auto calculation of all ball parameters: rotation, spin angle and speed. I hope this robot would be better than other factory robots. Actually now it has more functions than Amicus robot in a small size (except catch net and ifinity cycle), but with mobile app or IR remote control

Let me introduce the "TenniRobo".
Image
Altough I have a lot of ideas for futher development, I think it's ready for testing. I'm going to begin testing next week in Kharkov, Ukraine.

I've created the new website - http://www.tennirobo.com
and oficial Facebook page - http://www.facebook.com/TenniRobo
If someone has any idea, or suggestion, or he has just to say something - I will be grateful for any feedback.
Thanks! :whew:

Image

Author:  Debater [ 17 Mar 2018, 03:31 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Congratulations vedroitt.

How is it mounted to ensure stability during the feed process?

For it to be sold in the EU I think it will have to be submitted for electrical testing first. Are you intending to do that. If no, my concern would be what happens if I was to buy it and customs check it and find it hasn't passed the relevant EU electrical tests?

Sometimes parts wear out or break, what "after sales" support will you offer for "perishable" parts?

I watched the video on your website. Despite the same settings, there was quite a lot of variation in where the ball landed. What do you put this down to?

Thank you

Author:  wilkinru [ 17 Mar 2018, 06:40 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Fantastic project. I love where it is headed. I wonder if butterfly is watching this...

So I have a suggestion to make your robot better than the competition - add a rail on the end of the table that the robot can slide/move on. Having a robot just shoot the ball from the middle of the table is fairly limiting as you end up just not seeing certain angles. Allowing a robot to move freely at the baseline would allow for even more advanced drills.

The nice part is you likely could sell it as an add on.

Author:  igorponger [ 17 Mar 2018, 10:29 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

THE BEST AMAZING TT ROBOTS. I LIKE MOST.

https://ulfhoffmannroboter.wordpress.com/

The Iron Hand you never seen before.


PP Robot, made in China. The world's best inexpensive pingpang feeder.

Author:  vedroitt [ 18 Mar 2018, 03:31 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Debater wrote:
Congratulations vedroitt.
How is it mounted to ensure stability during the feed process?

Thank you!
It has crew-thread at bottom for mouting with standard tripod (for photo or video camera). The advantage of mount with tripod - you can mount the robot in any place near table (not on/near the table as usual robots), so you can achieve very realistic ball behavior (like human does)
Debater wrote:
For it to be sold in the EU I think it will have to be submitted for electrical testing first. Are you intending to do that. If no, my concern would be what happens if I was to buy it and customs check it and find it hasn't passed the relevant EU electrical tests?

It's really right and important question. I'll try to answer...
To be honest, at the moment I'm not ready for mass production. Actually, I have to test electronic and mechanic parts before, so it's too early for mass production. I'm going to do tests here in Ukraine with local users - it's easier to fix problems here, than somewhere in the world :) .
And you are right, for mass production certification is required. I read a lot yesterday about this, and I know that such devices should have a lot of certificates for EU market: RoHS, FCC, electric, etc...
It requires a lot of money (actually much more than I expected). I'm thinking about Kickstarter or Indiegogo, or other case to resolve this problem.
From the other side, I have long term experience of selling electronic boards to EU and other countries via "bravekit" website and Ebay account. And 99.9% of buyers have received their electronic goods without problems with customs. So, I think it wouldn't be a problem to ship the robot to someone, if this person wants it. Of cource, I undertsand that correct way - is to make certification, but it requires some time...
Debater wrote:
Sometimes parts wear out or break, what "after sales" support will you offer for "perishable" parts?

Now all parts in "Tennirobo" can be replaced without special tools - you should have only few screwdrivers, and maybe wrench 8/10mm for replacing wheel. I think parts will be available for replacement.
Debater wrote:
I watched the video on your website. Despite the same settings, there was quite a lot of variation in where the ball landed. What do you put this down to?

That video has been created spontaneously- as result there is some desync between mobile app video and main robot's video. Sorry for this. I will create other video soon, and I can say that now the robot can make predictable shots with same settings.

Author:  vedroitt [ 18 Mar 2018, 03:37 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

wilkinru wrote:
So I have a suggestion to make your robot better than the competition - add a rail on the end of the table that the robot can slide/move on. Having a robot just shoot the ball from the middle of the table is fairly limiting as you end up just not seeing certain angles. Allowing a robot to move freely at the baseline would allow for even more advanced drills.


You are talking just as my friend, I even checked the date of your registration at this forum :rofl:
Ok, the idea with rails is interesting, but I think this equipment will have too much weight/size to be shipped. In addition, it requires additional motrs and electronic, so the total cost will be too much. Because the robot mounted with tripod, you can place it anywhere near table - not only at the middle of table.

Author:  vedroitt [ 18 Mar 2018, 03:39 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

igorponger wrote:
THE BEST AMAZING TT ROBOTS. I LIKE MOST.
https://ulfhoffmannroboter.wordpress.com/
The Iron Hand you never seen before.

I've read somewhere that it's fake. Sorry if I'm wrong. :oops:

Author:  haggisv [ 18 Mar 2018, 15:28 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Great project! :clap: :clap: :clap:

If the device uses a standard 12V supply (one that's already approved), there should be no further safety risks, and approval should be much easier (and cheaper), would it not?

Author:  vedroitt [ 18 Mar 2018, 16:51 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

haggisv wrote:
Great project! :clap: :clap: :clap:

If the device uses a standard 12V supply (one that's already approved), there should be no further safety risks, and approval should be much easier (and cheaper), would it not?

Yes, it uses standard 12V power supply, so this sertification could be easy. But the device also uses Bluetooth, it requires additional sertificate.

Author:  vedroitt [ 25 Mar 2018, 18:02 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Here is the short video about tests

Author:  haggisv [ 25 Mar 2018, 19:53 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Looks fantastic to me! :clap: :clap: :clap:

Towards the end, you show the robot shooting balls at a player, and there is a long wait between balls. Is this intentional, or does it take the robot a long time to adjust spin for the next ball?

Author:  vedroitt [ 25 Mar 2018, 21:36 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

haggisv wrote:
owards the end, you show the robot shooting balls at a player, and there is a long wait between balls. Is this intentional, or does it take the robot a long time to adjust spin for the next ball?

It's just for example - interval is about 3-3.5 sec (I don't remember now :) ). In this video the robot shooting balls in series with one preset (setup) with constant motor's speeds - it means that it doesn't have to adjust spin for each ball. Actually, in this mode robot is able to shot about 100-120 balls per minute (0.5-0.7 sec between shots).
But, as you probably understood, motors can be auto reversed for adjust selected parameters. In the worst case, when any motor must be reversed from +9000rpm to -9000rpm (maximum positive to minimum negative or visa versa ), the interval between shots would be about 3 sec. But this situation occurs hardly ever - usual motor's speed is about 4000-7000rpm
Actually, this time can be reduced at 30-40% by using more powerfull power supply unit, but it will increase the price of the system.So there is a compromise between a cost and functionality.

Finally, there can be 3 cases:
1) with reverse of any motor from max to min or visa versa - minimum interval is about 2.5-3 sec
2) with reverse of any motor from middle to middle spin - minimum interval is about 1.5 sec.
3) without reverse of any motor - minimum interval is about 0.5-0.7 sec. It's a case of "one preset mode", or "one preset to different zones" mode, or any series without reverse

Author:  vedroitt [ 23 May 2018, 20:53 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Yesterday we made video about real training process with the robot. I need some time to prepare this material, but for the moment here's a very short video from yesterday.

Author:  vedroitt [ 30 May 2018, 02:02 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Hi all!
We have made cool video about playing with TenniRobo using programs.
Of course, the robot can make very strong spin, but our main goal was to create REALISTIC balls - as human makes in real game.
In this video you'll see:
1) serve with back spin - top spin to right zone near player - top spin to central zone near player
2) balls with back spin to 3 different zones
3) balls with top spin to 3 different zones with 60 balls/minute temp



For English please turn on subtitles.

Author:  Debater [ 01 Jun 2018, 03:14 ]
Post subject:  Re: Homemade table tennis robot with Android bluetooth contr

Looking for good vedroitt, I particularly like the serve replication.

Can you make a video showing how to program the robot when you move the location of the robot from centre of the table to say 5 feet back and to the left?

Keep up the excellent work.

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