Archive for April, 2010

My first robot!

My first electronics project, for that matter. I am currently taking an electronics class at my high school, and as part of the course, we are required to order and build an electronics kit. Since the kits provided were, in my opinion, too easy for me, I decided to order my own parts and build a remote-controllable robot based around an Arduino. I will try to throw together a haphazard build log here.

My first task, I decided, was to design and build a DC motor driver capable of driving four motors. I designed the PCB using KiCAD (see the schematic here and the PCB here) and ordered it through BatchPCB.

I wanted an omnidirectional robot. Both to save cost and for the additional wow factor, I decided to make it three-wheeled (kiwi drive). It will be good experience for next year’s FIRST competition anyway.

The following is my bill of materials, including where I ordered the products and their prices. I ordered many extra parts from Digi-Key so I could get lower bulk prices. I ordered the USB cable because I had too few and the extra transwheel in case I messed up while drilling holes in them. As you can see, I also took advantage of samples offered by some companies. I actually ordered samples of accelerometers and many other components not listed here that I thought may be useful in the future. Extras are indicated by an asterisk.

STMicroelectronics – $0

  • 3x* L298HN motor drivers (sample)

Keystone Electronics – $0

  • 4x 2-terminal blocks (sample)
  • 2x* 3-terminal blocks (sample)

BatchPCB – $20.06

  • 1x Custom-made four-motor driver PCB

SparkFun Electronics – $24.75

  • 1x RF Link Transmitter – 315MHz
  • 1x RF Link 4800bps Receiver – 315MHz
  • 1x Resistor Kit – 1/4W
  • 1x Polarized Connectors – Crimp Pins
  • 1x Heatsink Compound – ST350

Pololu Robotics & Electronics – $77.41

  • 3x 35:1 Mini Metal Gearmotor
  • 2x Pololu Micro Metal Gearmotor Bracket Extended Pair
  • 2x Pololu Universal Aluminum Mounting Hub for 3mm Shaft Pair
  • 1x 0.100″ Breakaway Male Header: 1×40-Pin, Straight
  • 1x 0.1″ Crimp Connector Housing: 1×2-Pin 25-Pack

Kornylak Corporation – $15.20

  • 4x* FXA208B (2051-1/4BX) CAT-TRAK transwheels

Digi-Key – $18.90

  • 1x* USB A-B (Q361-ND)
  • 10x* CAP 470UF 50V ALUM LYTIC RADIAL (P5185-ND)
  • 10x* CAP CER .1UF 100V X7R 0603 (490-3285-1-ND)
  • 18x* DIODE SCHOTTKY 60V 2A SMA (497-2461-1-ND)
  • 50x* RES 270 OHM 1/10W 1% 0603 SMD (311-270HRCT-ND)
  • 10x* LED GREEN CLEAR 1206 SMD (160-1404-1-ND)
  • 10x* LED SUPER RED CLEAR 1206 SMD (160-1405-1-ND)

Subtotal: $156.32
Total S/H: $18.39
Total: $174.71

All orders except those from BatchPCB and SparkFun have arrived. I will elaborate in the next post.