MOC in progress: beer/soda from fridge serving robot

[AlmightyArjen]

Thanks for the comments, I appreciate it!

And about my electronic skills: I got the NXT motors working a bit but I dropped the USB programming cable on the circuit board. Now it has somehow a short circuit and I don't know why: the circuit board must be resistant to small impacts like that. I guess I'm going to search for the error in the electronic jungle... ;)

[LEGO Train 12 Volts]

Oh this news sucks!

We all want that robot operative for the beer!

[AlmightyArjen]

I found the problem yesterday, the short circuit was due to a design flaw in the circuit board: the heatsink of a motor controller (which is connected to GND) touched the 5V pad of a resistor.

I'm back on programming the NXT motors again :)

[Legogal]

This is impressive! Would an automatic door opener (like they use for the disabled) have enough strength to pop open the rubber seals on the fridge) work? These openers are mechanical and exert a strong push on doors.

Better yet, how about installing a Coke machine loaded with all of your favorite drinks? Your robot hits the correct button, and picks up the cold drink from the chute.

Wait, are you drinking your beer cold? And your are Dutch? Are you ill?

[AlmightyArjen]

Do the Dutch have the image in the US of drinking their beers warm or something?? An automatic door opener would work, but I want the robot to do the whole thing, including the door opening part

[Captain Green Hair]

Ha that's great, you can kick your GF out the house then. Can I pre-order one?

[Doc_Brown]

Any damage due to the short circuit?

We Aussies drink out beer ice cold! :P

[AlmightyArjen]

Surprisingly no damage because of the short circuit. The 5V voltage regulator became very hot; that's how I noticed the short circuit, I literally smelled it! But it survived! Meanwhile I've got the NXT motors completely working how I want. They are controlled by another microcontroller and I've written a program for that controller that it only has to receive a new position (sent over a serial bus) from the main controller and the motors run automatically into place. During the weekend I'll be busy with programming it to actually open the fridge, can't wait!

And about pre-ordering one: it has costed me about €1000 by now , If I include labor at 20€ an hour (and that's cheap!) to build another one, I come to a total of at least €5000... Still want one?

[AlmightyArjen]

I got finally the robot opening the fridge! This was so far the most complex movement and I'm glad it works just fine. No lucky shots (i've had them though), it opens the fridge every time I run the program :)

[Doc_Brown]

This is absolutely amazing@!

You explain it soo well!

Great job and I sure can't wait to see the final design.

[AlmightyArjen]

Thanks! The final design will take some time though, I want to activate the robot through bluetooth on my android phone so I need to write an app for that. And since I've never done that I first have to learn that ;) But first selecting and grabbing a can...

[AlmightyArjen]

I finally got time to continue with this robot! This time the challenge was to grab multiple cans/bottles from the fridge. This means that the robot has to store the cans or bottles somewhere, to get its arm free to get the next can. I first came up with an extra robotic arm on top of the robot that grabs the can from the arm that reaches into the fridge. This second arm could place the cans behind the robot. But I found out that the cans are quite heavy and I would have to use a big megablocks crane to be able to move the cans, which would add too much weight on the robot. So I thought about an extra arm below the first arm that reaches into the fridge:

But I found out that also in this way the cans were too heavy, making the pneumatic cilinders extract on high velocity which resulted in less air pressure in the grabbing mechanism which let loose of the can. So I needed to come up with something else. And then I came up with this... ;)

In theory it can now bring me drinks from the fridge. Now I have to write an Android app in which I select which drinks and how many. I've never programmed an app before so it'll take some time :D

[Rishab N]

This is really turning out to be epic!

[KopMaister]

you know! when i first looked at this topic i was like: "yeah right!"

but that changed fast.

i'm so looking forward to see it in full action! you are a true genius!

[AlmightyArjen]

you know! when i first looked at this topic i was like: "yeah right!"

but that changed fast.

i'm so looking forward to see it in full action! you are a true genius!

Let's just say I've put some effort in it to make it work ;) The hard part has been accomplished, I think I can manage to write a simple app to complete the whole project :)

[aol000xw]

Omg, behold the killer drone with its choking claw!

[TasV]

How do yo find the compass sensor? We have a Hitechnic compass sensor and find that every little bit of electromagnetic interference, from things like TVs etc, affects its function resulting in very poor navigation.

[AlmightyArjen]

Omg, behold the killer drone with its choking claw!

That's the alternative program that I can download into the controller ;)

How do yo find the compass sensor? We have a Hitechnic compass sensor and find that every little bit of electromagnetic interference, from things like TVs etc, affects its function resulting in very poor navigation.

I know the problem. I use an HMC6352 compass module and I have also encountered lots of problems. The trick is to navigate on your furniture (distance measurements are very acurate) and make the robot drive short distances between the compass measurements. Doing so, you can more or less make the robot go towards the spot you want it to go...