[michaelt]

> Seems trivial

Said like someone who's never tried it :)

For a start you're going to need a camera. Maybe more than one. You want depth sensing? Even an cheap choice like a RealSense is going to add another $250 to your costs. And you'll need a sturdy mount for it, the robot's going to vibrate the table and you don't want to suffer motion blur.

Got the camera in a fixed location, over the area you're picking from? Then the robot's going to block the camera's view when it reaches in. No real-time hand eye coordination for you. Putting the camera on the robot's wrist? Now you've got motion blur problems - and reliability problems, because normal USB cables aren't designed for continuous flexing. You've also got a gripper in view all the time - and now the camera moves, things are always out of focus.

The reach of the arm isn't long enough to give you many bins to drop items off into, considering the number of lego parts there are. The longer you make the arm, the greater the torque at the shoulder joint. Making the motors bigger? Now the elbow motor is heavier. Gearing them down? Now you've got gear backlash.

Your Dynamixels will break, for some reason. Maybe eventually you'll figure out why. In the meantime, $50 each please.

Parts like the small satellite dish https://www.bricklink.com/v2/catalog/catalogitem.page?P=4740... will prove very hard to grasp. And there's like 50 different colours, you're going to need to know your way around lighting and camera settings if you want to reliably tell transparent light blue, transparent medium blue and transparent dark blue apart.

And that's before you get into questions like how to tell a 2x4 stud brick apart from two 1x4 stud bricks next to each other - or how to grasp a brick when an adjacent brick is blocking you from getting in with the gripper.

Every single one of these issues is solvable - but by the time you've solved them all? You could have hand-sorted that lego 20 times over :)

[sgu999]

> Even an cheap choice like a RealSense is going to add another $250 to your costs

fyi, Luxonis is selling some for $150, I'm still meant to try them but they look quite good

[r2_pilot]

I happen to use a few of their cameras, and they generally work as advertised (satisfied Kickstarter backer for OAK D and OAK D lite, probably going to buy the OAK D pro at some point). But, while I did indeed pay less than 250 for them individually, their current active depth offerings are $350(and while my oak d is fine for my lit, varied environment, I do often wish it was a little more accurate). I thought the Lite was also around $200 but it's actually $150 as you said. It's a pretty good little platform for the price. Be sure to check out the experimental repo too : https://github.com/luxonis/depthai-experiments/tree/master/

[greggsy]

It’s trivial to fork one of the several open source projects focused on this problem.

[MOARDONGZPLZ]

They really spent a lot of time diving into the complexities of your question and I found it really interesting. Your handwavey, one sentence response without even an example (if there even is one??) is kind of rude in this context.

[4gotunameagain]

For example ?

[1] lists [2] which uses a robotic arm, but it is closed source

[1] https://github.com/360er0/awesome-lego-machine-learning [2] https://www.thirdarmrobotics.com/q_and_a.html