Project BrundleFab

Electronics

Arduino

Seed Studio SD Card v3.1 Shield

Well, connecting to an Arduino Mega2560 doesn't just snap on and work. You need to route some pins:

MEGA Pin	SD Shield	Function
ICSP1	D12	MOSI
ICSP2	5v	5v
ICSP3	D13	SCK
ICSP4	D11	MISO
ICSP6	GND	Gnd
D53	D10	SS

Use the arduino SD library, with a 'const int chipSelect=SS;' and you are good to go.

HP F4480

I am using a pile of trashed HP F4480 DeskJet printers as a source of motors, gears, and encoders.

Here are some information I have discovered about the internals of this printer:

Rotary optical encoder board

This board monitors the 1200 DPI optical encoder disk attached to the main paper handling roller in the printer.

It uses quadrature encoding, and can monitor both forward and reverse direction.

I am using the 'Encoder' library from the [1] Arduino library collection.

Pin 1 is the kerf on the CPU board connection

Pin	Function
4	Output A
3	Vcc 3.3v
2	Output B
1	Gnd

Linear Encoder

The HP F4480 printhead carriage monitors a 1200 DPI optical encoder strip, which is the feedback to the carriage motor.

Print Media

Granulated Sugar + Water

Process

1. Lay down 10mm of granulated sugar
2. Sift a layer of 1mm of granulated sugar
3. Apply 1mm droplets of (colored) water to the granulated sugar via a needle bottle (unknown tip size)
4. Go to 2. until part build volume is complete
5. Lay down 10mm of granulated sugar
6. Heat at 120C (250F) in oven for 1 hour
7. Let cool
8. Remove from build container, and remove excess sugar

Results

The resulting object was stiff, but easily crumbled. Water dispersion through the granulated sugar had an approx 5mm radius, and substantially filled in the interior of the part (wireframe cube).

Analysis

• Droplet size should be smaller
• Either a finer granularity or pressure packing of the media should reduce the spot size of the print head
• A food safe adhesive should be tried to increase bonding strength
  • In-powder adhesive (such as meringue powder) activated by water
  • In-suspension adhesive (such as egg whites)

Powdered Confectionery Sugar + Water

1. Lay down 10mm of granulated sugar
2. Sift a layer of 2mm of granulated sugar, and pack down to 1mm.
3. Apply 1mm droplets of (colored) water to the powdered sugar via a needle bottle (unknown tip size)
4. Go to 2. until part build volume is complete
5. Lay down 10mm of granulated sugar
6. Heat at 120C (250F) in oven for 1 hour
7. Let cool
8. Remove from build container, and remove excess sugar

Results

Sugar did not re-crystallize, I suspect the cornstarch at fault here.

Analysis

• Powdered Confectionery Sugar is not suitable for printing, due to the cornstarch content.