SAND DRAWING ROBOT (new version) (Patreon)

Hi everyone!

This one took a while to make and I'm very proud of the result. I've been wanting to do an MkII of the sand drawing robot for ages and it seems that finally the stars have aligned. 

Instead of a single drawing tip moving sideways I've gone with 50 drawing tips moving simultaneously on a steel spine moved by two treads. I went with threads instead of wheels because I was afraid that the tips were going to brake the thing to a halt due to lack of grip on just wheels and I wasn't wrong, I needed to tune how much the tips where coming down because the combination of braking force plus lifting the entire thing was bringing it to a halt. The sand was extremely compact so the texts cannot be read very well but just to get the beach this empty got us waking up at 4:30 am two days in a row (I forgot the programming cable the first day) and we needed also to have that low tide that early in the morning, so we didn't have the luxury of being picky with the canvas.

The servos were fed by a 24V 6S battery through 5 24V to 5V DC/DC converters what in the end was a bit overkill but better safe than sorry. 

The signal to the servos was sent by two Arduino Mega 2560 - 25 servos for each Arduino and a third Arduino read the image to be written from an SD and sent it through a serial communication to the other two Arduinos. That Arduino was also sending the driving signal to the driving motors that were powered by a 12V 3S battery through two IBT4 DC motor drivers. There was considerably more wire length for one motor than for the other so I had to tune it a bit to make it go straight. 

The handle in the middle was an afterthought, after trying to hold it when it was almost finished to be more precise, there are not many places to hold it with all of that stuff on it. 

The trailer was a nice touch, half of the city is closed for motor vehicles and we had to park quite far from the beach to do the tests so a 5 star review for the trailer.

And that is basically it, many many many hours went just on wiring everything, which is something that I didn't foresee when I ordered the 50 servos. 

As always let me know what you think down below.

Thanks!!!!!