m&m sorter #3

Sorts m&m's by color
DeltaRobot-0.02.zip3.44 KB

Videos: http://www.youtube.com/watch?v=Pbb9GOWaL4g and http://www.youtube.com/watch?v=mPakG8p3MHE

Update: Added schematic for the vacuum system

Code word were: CHEAP!

Cheapest RC servos I could get, Cheapest Arduino, almost. Straws from mc donalds, icecream sticks, rubber bands, Lots of scrapped stuff just waiting to be used in the workshop. Solenoids in the valves were from old tapedrives, and the valves them selfs were from old bicycle tubes. Vacuum and pressure comes from an old aquarium pump, reshaped to make vacuum too.

The dark disk is a sun shade, had to add that before filming outside, othervise color detection made too many mistakes.

"Exploded view" of lower arm:

"Exploded view" of lower arm

Lower arm:

Lower arm

Lower arm about to be connected to bolt on upper arm

Lower arm about to be connected to bolt on upper arm

Lower arm and the moving platform:

Lower arm and the moving platform


Two valves, the lower one disassembled

The pin visible at the end of the yellow tube pin of the bicycle valve. The brass tobe above goes over the pin. Since the pressure uses in the robot is low, +/- 0.15 bar, I could go with these simple home made solenoid valves.

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This is a cracker. I think I missed something. what's teh disc thing that it keeps putting on top of the sweets once they're in the colour detector cup?


The black lid is to cancel out ambient light. Before I "invented" that, my home made color detector had an very high error rate, 30 to 40 percent, if I remember correctly. Now with the lid, it have not made a single mistake, and trust me, it has made several thousand detections.

and the no-tech video titles!

I tried several free video editing softwares. They all failed on me, or I did not have the necessary patience to learn how to use them, so at the end of the road I went for the low tech solutions.. And thinking about it I really do like to keep things simple when at all possible.

Very creative.

I am in the process of following your excellent example and building a Delta robot. I am looking at various gripper options. Your vacuum system intrigues me but I am a little confused as to how it works. Could you give us a schematic of the setup please.

Thanks for your contribution


I will make you a schematic of the vacuum system when I get home from work. If I can remember how it worked. The robot does not exist any longer. As an appetizer I will list the main components here: vacuum pump, pressure pump, two solenoid valves, suction cup and vacuum detector. Then some tubes and T-pieces. (now I have a list of what should be in my schematic later)

But that said, please do not hesitate asking questions about it. I did spend quite some time on that project, so I might be able to remember a little here and there.

I wish you good luck on your machine! (and remember to snap some photos while doing it, I forgot that)

Thanks for posting the schematic. One further detail, what did you use as the small suction cup? The black component on the red fitting at the end of the vacuum tube.I am having trouble getting a good seal on objects.

 I would also like to thank you for your code. The use of libraries makes implementation so much simpler.


It took me some time to get the seal tight enough too. The red thing is the "tubing" of a banana plug, the thing you hold on that goes over the actual plug. I use is only because its a little flexible and gives some distance. Inside the red "tube" there is a smaller clear one, the one that feeds the vacuum/pressure to the suction cup. Connected to the clear one is a black small rubber spacer of some sort, and over that, an other black foamy rubber thing.

Look closer at the pictures you will notice a small spring. That spring ensures good contact with the m&m but still without breaking either machine or object.

On the bottom line, every piece of the moving head is made from scrap, so I can't tell you where to buy the perfect small black foamy thing for a small suction cup, I simply have no clue of there it came from. Well, maybe the paper guidance system of an old printer. I usually pull them off and save them is my "small circular soft plastic thingys" box when scrapping printers.

 I am progressing slowly with my version of a delta robot. I don't think most people looking at your video realise the complexity of the task you achieved. I have a vacuum supply ( a little different from yours ), colour detection and a feed system for coloured beads set up. I now recognise the relevance of the vacuum detector in your schematic. What did you use to achieve this? This project is quite a challenge but I am really enjoying it!