Changes in design

 The toothpaste movement was first designed with a “crankshaft” movement. The 3D parts for the tooth paste dispenser were printed with a tight fit that the small engines wouldn’t be able to force the piston into the cylinder. The design is changed to a linear movement met gear and rack. The engine has a small gear to press the tooth paste out as slowly as possible till the load cell sensor shuts the engine down.

3d printed parts

The 3d printed parts came out bigger than expected, the project group members grinded the parts to the size that was designed.

New parts

The box 

The box itself is made of 6mm plywood plates, wood is chosen as material because it is cheap and strong enough. They are connected by a linear pattern of cut-outs. The 3D tool indent gives the opportunity to get the pattern of the cut-outs into the other plate. Eventually everything fits together and can be glued together.

  Door movement

The door movement is done by a 180 degrees servo engine. The engine opens the door with a connected double arm. One arm is attached to the engine and one arm is attached bolted to the door. The arms are connected by a M4 bolt and separated by a two millimetres thick washer out of plexiglass.  The arms are both made of three millimetres thick plywood. Plywood is chosen because it’s strong enough with a low thickness and because it’s a cheap material.

The door with the mounts

The door plate is designed out of 6mm plywood with cut outs for mounts that are applied on the inside of the door, we used 6mm because we needed a strong basement for the load cell. The sensor will give wrong signals when the mounts are too flexible. The mounts are made in a way that they get strength out of 2 ways in the door plate, horizontal and vertical. The mounts are connected to get more strength out of the design. The mounts that opens the door are only have horizontal connections in the door because the force is also applied in that direction.

Toothbrush

The toothbrush is made of wood because it’s still a prototype and this was the cheapest way to simulate a tooth brush. The toothbrush is based on two layers of six millimetres plywood and glued together to the final product.

Toothbrush mounts

There were 2 ideas at the beginning, first one with a U form profile and a pressing plate attached to a bolt that can hold the toothbrush. The second idea was to use the 3D printer with a clamp that was based on flexibility.  The decision is based on the curiousness to the flexibility of the 3D printed parts and to try something new.

The mounts of the toothbrush are based on the flexibility of the material that is used by the 3d printer.  The mounts are locking the toothbrush by the edges of 1 mm that are holding the upperpart of the toothbrush. The mounts open when there is pressure applied to the sides of the mount.

Engine mounts

The engine mounts are cut out of 6 mm plexiglass because there were holes required in the layer. Wood will be torn apart and plexiglass will be a possibility.  After that there are holes drilled in the plexiglass to connect it to the base plate of the box. This was a really hard process because the plexiglass melts or cracks fast. Eventually the task is completed with the technic of pecked drilling.

Cylinder mounts 

The cylinder mounts are also cut out of 6 mm plexiglass. The cylinder mounts are made a little bit smaller than the cylinder is to work as a clamp to hold the cylinder into place when the engine pushes.

  The cover 

The cover plate of the box is cut out of six millimetres plywood as a base that can hold the weight of the ipad. The cover and one plate of the box is milled on two areas to get a engravement for the hinges. The engravements are used to prevent that the cover edges and the box are scratching when the cover is open.

The inner cover parts 

The front face of the mirror and the walls are cut out of 3 mm to make it as light as possible. The walls are 5 centimetres high to give space inside for the mount of the iPad and the iPad itself. The cut out in the front face is for the camera. The cut outs in the walls are for wiring and a bolt connection together with a mount that will be able to hold the cover in a certain angle.

The parts to hold the cover under an angle 

The mount is made of 6 mm and will be grounded in the walls of the inner cover part. The two arms are connected by a m4 bolt and a fly nut to fix and loose them in an easy way. The mount is connected to the inner plate that will be attached above all the working parts in the box.

The cover and the inner cover parts is connected with mounts in the form of a L cut out 6 mm plate, this mount will be attached on 16 places.

  iPad mount

The iPad mount is also 3D printed. The first try failed, we tried to guess the thread of the original mount, it didn’t fit at all. The second try was successful, we tried it without the thread and designed only the mount plate with the arms to connected in the original mount. The only thing that was wrong that the mount plate was too long. It fitted after a cut and some grinding work.

Engine to gear connector

The engine to gear connector is a 3D printed part. The holes had to be drilled again but there was no grinding necessary in this part. This part connects the servo engine to the cross bar that is connected to the gear.

M4 nut locker

The nut locker is a square piece of 3 mm thick plywood with the form of the nut inside. The nut locker is glued to the wooden baseplate of the in between plate.

Operational descriptions

Box with cover plate

The box plates must be glued together with wood glue. The plate that is attached to the cover and the cover itself have to be milled first with a 10mm mill and finished by a 2 mm mill. The hinges have to be placed at the areas of the milling. The hinges are connected by m4x10 bolts with a conical head. The hinges are locked by M4 nuts with washers.

Tooth paste movement

Piston and cylinder

First attach the cylinder to the mounts and screw the bolt till the cylinder is not able to move in the mounts anymore. Put the O-ring on the piston and connect the piston to the rack with a M4x12 bolt and lock it with a M4 nut. Place the piston into the cylinder. Glue the cylinder in place according to the placement drawing.

Engine and support

Attach the engine to the mount by four M3x12 bolts and lock them with a washer and a M3 nut. After this take the gear connection and attach it to the engine with 8 M2x6 bolts. Connect the gear to the connector with the cross bar. Glue the mounts of the engine in place according to the placement drawing.

The support wheel relates to Lego materials. Put the wheel on the crossbar and move it into the right position in the hole pattern, lock it with the yellow locking parts. Glue the support wheel mount under the hole pattern and let it rest for a minute. Glue the mounts of the support wheel in place according to the placement drawing.

Door movement

Glue the mounts in place according to the assembly pictures. Screw the load cell to the lower door part with 3mm x 8mm screws, screw it with the load cell on the edges of the door part. Glue the tooth brush mounts to the load cell and the left door part, use the edges again to outline the parts.

Engine and the mounts

Drill the holes into the mount with a 2,8 mm bore and the speed as low as possible to prevent the production of heat in the plastic. Screw the engine on both sides with 2 M3x8 screws.  Mount the engine connection with 8 M2x6 bolts to the engine arm. The engine arm is connected to the arm with a M4x16 with a in between bush, locked by a M4 nut. The arm is connected to the door with a M4x16 and that one is also locked by a M4 nut.

Cover and inside parts

Glue the inside plates together with wood glue. Glue the ipad mount into place and slide the ipad holder in the ipad mount. Put the ipad in place. Glue the screen layer of plexiglass onto the wooden plate on the inside cover. Glue the camera also in place at the top part of the cover. Screw the raspberry pi on the located place according to the wiring diagram.  Glue the L links to the inside plates of the cover and to the cover itself to connect. 3 on the top and lower part and 5 on the sides. Divide the L links on the side parts with a distance around 7 cm.

Cover hold up mounts and locker

Place the mount of the in between plate holder on the location according to the location drawing. Bolt the in between plate to the mount. Glue the M4 nut lockers around the nuts and to the wooden plate of the mount. This will keep the nuts locked when you unscrew the bolts from the top. Bolt the mounts of the cover arms on the located places with m4x12, locked by m4 nuts. Bolt the arm to the mount and bolt the first arm to the second arm by a M4 bolt and a M4 fly nut. Bolt the upper arm to the side of the cover and the mount that is still left. Put glue under the mount and connect it to the cover plate.