Hardware

The following are materials and setup instructions for a very simple educational "arm farm" based on a Rotrics DexArm and a Raspberry Pi 4 or Jetson Nano 4GB.

Arm Farm Hardware Setup

Table:

• $11.52: 2ft x 2ft block of wood
• $3.68 * 2: 1in x 36in Wood dowel
• $2.18: 1in hinge
• $8.47: 1/4in magnets
• Misc: 1 1/4 to 1 1/2 in screws
• Misc: 4 3/4 in screws
• Misc: Superglue or equivalent

Construction

1. Cut 1ft off a dowel and then reconnect with the hinge
2. Cut 1ft off the second dowel.
3. Attach 1ft dowels from bottom at opposite edges (x-axis) of the board approximately in the middle (~1ft) from edges (y-axis) using the longer screws.
4. optional: Drill a small divet in center of the top of dowel that doesn't have a hinge and glue in a magent
5. optional: Mark where the hinged dowel lands on top of the magnet and drill out a small indent to place second magnet (this helps w/ alignment)
6. Remove rubber pads from Rotrics robot and screw into the edge of the board (shorter screw) -- again centered

Cost: $25.85 or ~$30 with glue and screws and <1hr of labor

Grid: Execute Wide Grid GCode or import two adjacent copies of Grid svg to burn a 400mm wide by 160mm tall grid onto the table. Note: Use 90% of laser or lines will be very light/spotty.

Robot is Rotrics DexArm:

• $999 USD for Luxury Kit (incl pneumatic gripper and laser) or
• $659 USD for Base kit + $259 USD for Pneumatic Gripper

Blocks Small blocks can me made by cutting up the remaining Dowel or via the 3D printer attachment

Overhead Light Recommend some overhead or bar lamp lighting (minimal shadows) to evenly light the surface

Arm Farm Compute

Computer:

• $119.95 for a Raspberry Pi 4 Kit with 4GB of RAM

Jetson Nano Option:

• $90.00 for Jeton Nano
• $14.99 for 5V 6A 30W Power Supply
• $7.50 -- $18.99 for Micro SD

Camera and Accessories:

• $29.95 for 8mp Raspberry Pi Camera
• $5.40 for 1meter camera cable
• Misc $26.99 for USB/Bluetooth Keyboard & Mouse
• Misc $84.99 for Small touchscreen is completely unnecessary

Cost: $150ish or ... more if you buy more stuff

Camera Connect

• Cheap: Tape or Zip-ties
• A little more: 3D printed clips see CAD Directory for files. These can be easily printed and and tiled around the provided 3D printer platform if DexArm attachment was purchased:

sudo usermod -a -G dialout ybisk

Torchvision git clone https://github.com/pytorch/vision.git -b v0.8.2; cd vision; sudo python3 setup.py install

LCD Displays

• $11.99 for 2-Pack 16x2 LCD Display

Install drivers and see demo code: LCD from RPi Guy and sudo apt install python3-smbus

Might want to try sudo apt-get install i2c-tools and sudo i2cdetect -r -y 1 to see i2c setup

Notes for Jetson Nano (WIP): In general things don't line up directly NVIDIA Jetson Nano J41 Header Pinout. Here we just have to re-orient:

• GND = 6
• VCC = 4
• SDA = 3
• SCL = 5
• Code:
  • sudo i2cdetect -r -y 1 shows 27? Awesome.
  • Set the BUS_NUMBER=1 LCD Driver
  • Remove the RPi import. This won't work even if you install the library.