Week17 Mechanical and Machine

The X-Y painter

We built a framework with aluminium profiles.

We cut the material with grinding wheel. Later we learnt that we should not do this. This kind of grinding wheel can be used for steel but not for aluminium. It was dangerous, as the temperature is high and the aluminium might melt and stick on the whell, which might cause the wheel break and splash out.

With these aluminium profiles, step motors, arduino uno with CNC shield and step motor drivers, we built a x-y painter.

We use Universal Gcode Sender to control the machine.
Before using, we need to calibrate the steps.

Type $$ to view all the settings, and type $id=value to change the setting.

There are also some online tools/ chrome plugins to convert image into gcode (.nc) file and send the code through serial port.

The x-y machine seems easy, but we still encountered several problems. Need to be careful that the nuts are fit into the slots; should make the framework straight before tighten up every screws; should adjust the pulleys into a line.

At first we connect the belt as the first picture below, and it was tight somewhere but loose some other place. Cut a new piece of component and it is much better then.

The Egg Painter for Stroboscopic Animation

PanChange, Shreyas and I decided to created egg painter for stroboscopic animation, similar as this video. PanChange works on the machine structure design, Shreyas works on the electoric components and I work on the interface app.

The first design was as below:

Shreyas might add more components such as coin collector to make the machine more interesting. (You must pay to get your egg painted)

And we would like to have an app for the machine, so user can draw the pattern.

We updated the design so it can paint on eggs, balls and cylinders. (Step motor P is used to paint eggs or balls, and step motor T is used to paint cylinder.)

(designed by PanCheng)

The android code will set following parameters directly:
* the angle servo need to set, for pen down or up * the movement of setp motor R * the speed of step motor B * the speed of setp motor P and T are calculated accordingly, range as the pictured showed below

Inspired by G-code, I defined the E-code for our egg painter machine.

I wrote the app by APP inventor. But there were two big problems:
First, app inventor runs too slow, so I cannot get nice animations.
Second, the stroboscopic animation requires specific patterns that can match with the flash nicely. However, draw by finger on the phone screen cannot be so precisely, and the animation will be messy.

So next step I will try processing for the interface.