Anti-burn Box

In this project which took place in a rapid prototyping class, we have designed a box that prevent a 3D printed hand to be burn by a lighter.

This hand automatically go back in its box when there is a flame under it.

Arduino UNO

Servomotor S90

Flame sensor

A breadboard

Breadboard wires

3mm thick MDF board

PLA for 3D printer

To make this projet, you have to realize the circuit above.

The pseudo code is the following:

Infinite Loop :

IF(triggered sensor):

hand position = in:

wait 0,5 s

ELSE:

hand position = out

Full code

Create this hand with a 3D Printer using the following file.

Design the boxe to contain the Arduino circuit and with a hole large enough for the hand.

The model was found on festi.info/boxes.py/ and modified for the project. Used the following files to create the box with a laser cut on a 3mm thick MDF board.

Before cutting the whole box, do some tests to verify that the tolerance chosen here is compatible with your laser cutting machine, and that two walls fits together well. If not, modify the burn correction parameters on festi.info/boxes.py/BasedBox?language=fr when generating the box.

The 3D design of gear and rack has been done on CATIA V5 using a 3D model found on traceparts.com.

Then, the file was exported on Rhino 7 (see supporting file) to create the system with a laser cut on a 6mm thick MDF board.

1st step:

Assemble the box without the top.

2nd step:

Put the Arduino circuit inside

Fix the flame sensor and the rack on the hand.

Fix the gear on the servomotor, and the servomotor on an inside wall of the box.

WARNING: beware of fixing the servomotor at the good height so the hand can still pass through the box hole.

3rd step:

Create the guidage system for the rack. To do that, you can:

• put a screw on a side wall of the box at the right height so the rack can land on it
• do a hole of the rack size in the back wall of the box (see picture)

You can see on the picture the length of the rack outside the box when the hand is outside and inside.

In our version, we extend the rack with a piece of wood but you can do it in one part.

Alternative version: create a bigger box and put another screw

4th step:

Verify that everything is working and close the box.