The bill of materials is for $N$ (25) pendulum segments and 2 motors.

Mechanical parts

Off-the-shelf components

Springs:
- T048-360-406R
- https://www.industrial-springs.com/t048-360-406r
- Qty.: $N+2$ (Recommended: $2\times N$)
- Note: With suitable changes of the 3D models of pendulum block, different springs can be used.
Aluminum profiles
- 40x40, 8 mm slot I-TYPE.
- Total length: 0.07 m $\times N$ + 0.6 m (2.1 m for 20 pendulums)
  - Main rod: 1 $\times$ 1.5 m
  - Side rods: 2 $\times$ 0.3 m
Pendulum rod’s:
- Aluminum round bar, Diameter: 5 mm
- Total length: 0.15 m $\times N$ (3 m for 20 pendulums)
Bearings:
- 6804-2RS: https://a360.co/3uMFW8I
- Qty.: $N$
Screws:
- M6x16. Qty.: $N + 2$
- M3x14. Qty.: $2 \times (N+2)$
  3D-printed components
Pendulum support: https://a360.co/3wYKgEr
- Qty.: $N$
Pendulum’s weight holder:
- https://github.com/aa4cc/The-Frenkel-Kontorova-laboratory-model/blob/main/cad/weight_holder.stl
- Qty.: $N$
Pendulum block: https://a360.co/3JjEwYM
- Qty: $N$
Motor support: https://a360.co/3M9fMnV
- Qty.: 2

FPGA development board:
- DE0-Nano Development and Education Board
- https://www.terasic.com.tw/cgi-bin/page/archive.pl?No=593
- Quantity: 1
Rotary encoders:
- AMT132S-V
- https://www.cuidevices.com/product/motion/rotary-encoders/incremental/modular/amt13-series
- Quantity: $N$ (+ 2 if it is desired to measure angles of the motors)
Motors:
- Nema 17 1.8° stepper motor
- Quantity: 2
- Note: different motors can be used
Motor drivers:
- Pololu Tic T249
- https://www.pololu.com/product/3138
- Quantity: 2
- Note: If Nema 17 stepper motors are used
Adapter for FPGA Shield
- 15W, 5V DC, 3A
- Qty.: 1

PCB:
- Custom-made. Please, visit: https://github.com/ptrbroz/AA4CC_FK_model_sensors/
- Quantity: 1

Components: