OOAK Table Tennis Forum

I got frustrated waiting for Trainerbot and as a side project started building my own Table Tennis robot. We got an initial prototype working a few months back and some of our friends wanted one. So we polished it a bit and have started shipping locally in our city.

I do not know if any other robot uses a computer to power their robot, we use a raspberry pi along with 3d printed and laser cut parts.

Take a look at our Table Tennis Robot

The user connects to the robot via wifi and uses a browser to control the robots.

What do you guys think? Is there any feature that you would like (low cost camera for recording, voice control) since it's easy for us to add these features

Interesting. From India, apparently. One thing it lacks is a ball return mechanism, and I am not sure if the catch net comes with the robot.

Iskandar

The robot is placed on the table, we have not provided a catch net as this can be used with any catch net available in the market

Kudos for the remarkable engineering! To be successful, I believe it will need a ball recycling system (and a net.. no prospective purchaser wants to worry about procuring a compatible net from elsewhere, and you wouldn't want your robot's marketability dependent on another company's product), as well as greater consistency with placement and interval timing.. properties that probably depend on steady ball feeding/uptake by the wheels.

I think a few more photos would be nice. The video is shot from too far away to see much of the actual robot. Here's the only one on the website:



This looks more like disassembled components than a complete robot - no ball hopper visible, for example. I don't know if it'd be worth putting in a ball recycler at this point, it'd be usable without one, but it would be good to have a catch net. Designing the ball recycler would be a major bit of effort, maybe a later model at twice the price. The other problem I see is shipping - I wonder what it would cost to get that robot here. Maybe you could sell kits, or two or three "short" kits in various degrees of completeness (maybe you could supply plans for the ball hopper, and plans so that people could cut some of the parts out of plywood or 3D print them themselves). Kits would be a lot cheaper to ship.

Power is an issue. I suppose this runs off a AC converter/power supply (like one you'd get with a laptop computer). It'd be nice if you had a battery box option, like the iPong has. Nice to be able to avoid all those power extension cords, and it'd give you flexibility when it comes to where to put the table.

Iskandar

Thanks nathanso and iskandar, those are some good insights.

As far as adding a ball recycling, we have added an option in our circuit and we plan to add that feature as an extension. We do supply catch nets locally but they are easily available for around $50 - 100 and once we have a few orders we can talk to some manufacturers who can supply this

The head is now covered, I haven't had the time to add image as we have a few orders that we are working on to create the robot.

At this point the idea is to make it easy to assemble and create one yourself, if we went ahead and created a plastic mold like other are doing that would result in a significantly higher upfront investment as well as raise the cost higher up for the customers.

It is in an early stage and we are still looking into shipping but one of the design decision was to go with the model used by 3d printers.

A couple of things we are looking at
Most people have access to services that provide 3d printers and laser cutters and can order a raspberry pi online. We can just ship the electronics and that would significantly reduce the price for the user
Another option is to have partners in each country who have expertise in assembling and they can ship to for less inside their country.

For power we are using power supply like a laptop, it should be easy to get it working on battery but have not had a chance to look at it.

For small-scale manufacturing 3D printed parts should be fine. Injection molded parts probably wouldn't be worth it unless you're going to sell several hundred units. The large rectangular parts COULD be cut out of plywood (by the end user), so that would be an option if you supply the other parts. Partial kits would have parts that you supply (motors, wheels, software, brackets, for instance), but the builder would have to make, buy or print the other parts themselves. If the user had to make the larger parts it would really save on shipping.

Iskandar

Updated design and different drill demonstration

Looking good!

Just needs a net + recycle system...or maybe not?

One of the downsides of the butterfly robot is that it always shoots the ball from the middle of the table. What would be amazing is to put a robot on a rail to do other angles. Drills could get increasingly complex from that.

Imagine getting served short to the wide forehand and then the next ball to your backhand? Sure this can be done with current robots but not nearly the angle one can see against real players.

Ideally you could have a robot on a 2D plane behind the table that could move around and still have a ball recycle system. This would allow extra variation in serves and other shots. Almost getting to the point where the robot could just block for you then...

I never though of that... actually even most multiball feeders don't move from side to side. Good point. Maybe instead of having the robot move, put three robot heads in a row, all slaved together? Now we're talking real money and complexity, though...

I think we could live without a ball return, IF there were a net, and if the ball hopper were large (100-150 balls at least). The one that comes with the iPong is quite good. It's got a drain hole in the middle, you set up a box or a bucket under the hole to catch the balls, which can be dumped back in the hopper.

What's the maximum feed speed (i.e. balls per minute)?

Iskandar

While movement is possible from an implementation view it is probably easier to have multiple heads and then co-ordinate between the different heads.

We wanted to keep the cost as low as possible so we did not add recycling system + net as a part of the robot.

so recycling net is something we thought of and planning to add it as an addon that can be plugged in. We will look into this if enough people want it.

Right now we have three feed speeds (1.5 seconds, 1 second and 0.8 ).

With multiple heads, you'd probably need some sort of cue to tell which head is going to fire next, though - maybe a light comes on above the head right before it fires.

Iskandar