Cheap Braille Embosser (La Picoreuse)

Presentation

"La Picoreuse" is a cheap (75€), easy to build A4 braille embosser.

This project aims to serve as a first step or a basis for reflection for other makers in order to provide an alternative to very expensive market embossers (3000€)

The idea of this project is borned to respond to the needs of the ParACheval association

The cutting and soldering part could be realized thanks to fablab-sud31 (Cintegabelle)

Sources

OpenSCAD Sketch and DXF files: thingiverse

All source files: github

Frame

• MDF - 479*302*6mm (5€)
• MDF - 224*204*3mm (3€)
• Piece of Bicycle inner tube
• 2x Old printer metal rod Ø6mm
• 1x Old printer metal rod Ø8mm
• 1x bronze ring - BNZ8-10-6 (1.5€)
• 3x bronze ring - BNZ6-8-8 (5€)
• 5x Nylon cable tie (0,5€)

Motors

• 2x Nema17 steppers (20€)
• Pulley / Belt - GT2 20 (4€)
• Connection Ø5mm to Ø8mm - Ø14mm extern diameter (2.5€)
• End-of-travel switch (0.5€)
• Solenoid 30 x 15 x 13mm (2.5€)

Electronic

• Arduino Uno (10€)
• Motor shield (type Adafruit Motor shield V1) (9€)
• TIP120 NPN (0.5€)
• 1N4004 400V 1A Axial Lead Silicone diodes (0.05€)
• Resistor 2.2kom (0.05€)
• 12v transformator (10€)
• 12v jack femmal connector (0,5€)

Cut frame

Download the 2 files and cut them using laser cutter (cnc may broke some of the small parts)

Indicative laser cutter settings (100W laser cutter)

• for 6mm MDF: 13m/s at 80% power
• for 3mm MDF: 30m/s at 80% power

If you are looking for up-to-date files or if you need to adapt them to a particular purpose, you could download OpenScad sources here

Prepare boards

Sand the boards G and E and fix 5mm bolt to E board (could be done later)

G is sanded to avoid blocking the paper

E is sanded to avoid blocking solenoid wires

Adjust the length of the belt

Block one of the ends of the belt with a nylon cable tie (make sure to put the head of the collar in the plane of the belt)

Follow the path indicated on the picture attached to the belt (put 2 nuts on the big axis to be sure to have the right dimension)

Attach the second end with a nylon cable tie

Assemble the solenoid support

Attach belt connexion bold on each side of the solenoid.

Attach bronze ring with nylon cable tie.

Attach Solenoid with bolt. Be carrefull, if the bolt is too long it may cramp the solenoid moves a bit. If so add some rings to reduce the thread length

If the belt is already at the correct length you could add it at this step.

Assemble main frame

Screw the Arduino card to the board H

Embed boards F, G and H in board B

Embed board C

Slide board F so that it blocks both sides

Leaf drive system

Nest the leaf drive system

Notice: If your leaf drive system is not the same size, you may have to adapt board G in OpenScad sketch (here)

Damping Rubber

Insert the damping rubber of the punching system. To increase rigidity it could be useful to glue last layers of rubbers togethers.

12v connector

Add 12v connector on C board

End-of-travel switch

Add end-of-travel switch to C board. To build a more secure machine, it is also possible to add an other switch to B board.

Notice: in the video it is added to B board because it is another version of the machine

Build X axis

Add D board on right side.

Slide the 6mm metal bars starting with the bottom one.

Install the strap and make it protrude into the notches on each side

Connect wires as shown in the shema.

It may be useful to use pluggable connectors for solenoid and end-of-travel switch.

Connect electronic

Plug motor shield to Arduino board

Pass Y motor wires throw C and D boards holes (the X motor wires must stay in)

Add solenoid control part

Screw the power wire (motor shield and solenoid control part togethers)

Finish frame assembly

Insert board I on the back (the one with holes)

Embed board A on the left side

Slot board E without forcing. If it stucks, make sure to run the Y motor wires at the back of the board E, to achieve this, just pull the wires a bit up from the inside of the electronics part.

Mount the X stepper motor sideways to include the belt

To hide wires, the connector must be embedded in board A

Connect wires from the inside once the engine is in place.

Insert the bronze ring on B board

Insert 8mm metal rod

Add 8mm to 5mm connector

Add Y stepper motor

Tighten stepper and connector screws

Download

BraillePrinter.ino (file on bottom) or up-to-date version here

Adafruit motor lib

1. Connect USB to PC
2. Plug 12v power supply
3. Insert a A4 sheet (160g should be good)
4. Open Arduino Serial Monitor and type

{ abcdefghij# klmnopqrst#uvwxyz

• { : initialisation
• # : start a new line (because, on serial tool, return validate sending instead of including newline char)
• a..z : char convert to 6 dot braille

Rq1: The syntax should be updated in future version to include configuration

Rq2: This is a old video version (TODO: update it)