Let's Robot

Welcome to the Let's Robot network. You'll find comprehensive guides and documentation to help you start working with Let's Robot as quickly as possible, as well as support if you get stuck. Let's jump right in!

Robot Hardware 101

There are thousands of ways you can mix and match components to get your robot working on the site. First let’s understand what each component does and why you would want or need it.

Example of a hardware build. (This is just one way of building a robot, not necessarily the suggested or only way.)

Example of a hardware build. (This is just one way of building a robot, not necessarily the suggested or only way.)

Hardware

  • Microprocessor for the Robot Brain

    • This is usually a Single Board Computer that has a micro processor on it. Most of us use the Raspberry Pi 3 b+. This is because it is doing the data crunching for live streaming and running TTS (Text to Speech).
    • You may be tempted to use a previous version but from our testing we've found the Pi 3b has trouble with dual band 5ghz/2.4ghz wireless access points, and any place with multiple access points. The Pi 3b+ is more robust at handling different wireless conditions. However it is a bit more power hungry and can often have under voltage issues with poor quality USB battery packs.
  • Micro SD card for your Raspberry Pi

    • Any cheap 8gb card will suffice.
  • Camera for streaming

    • The Logitech C920 is highly recommended, the onboard video encoder, stereo mic, wide field of view (FOV), auto focus, and automatic light and color focus, creates the best streaming experience for most robots. If you want to save money here try bidding on them at Ebay.
    • The Raspberry Pi Camera also works but has a very narrow FOV so you’ll likely need a fisheye lens also.
  • Microphone for the audio (included on the C920)

    • If you are using a camera without a built in mic, there are plenty of USB mic options.
  • USB speaker for the TTS robot voices

  • Power source

    • You can use AA’s but they won’t last long.
    • 18650 Lithium batteries are a good choice, just be careful, they can ignite.
    • We highly recommend the Talentcell 12v and 5v dual out USB Power Pack. This should be paired with a step-down regulator below to get the right voltage to the motors, the Pi, or both.

Power Source Issues

USB battery packs that don't have over 2.0 amps are a constant challenge, especially for the Raspberry Pi 3b+. It is rare that a USB battery pack actually performs at its rated specs.

Often 2X USB port packs can't provide enough amps when both ports are in use. After buying two or three that aren't good enough you'll end up spending more than just going with our above recommendation.

It is also important to have two separate channels of power, one to power the motors, and one to power the Pi so voltage spikes don't cause under voltage issues for the Pi.

  • Step Down Regulator

  • Motor Controller

    • Adafruit Motor Hat comes highly recommended as there is a lot of support for this controller; it does require soldering.
    • The L298N H-Bridge
  • Motion Components (Servos, DC Motors, Steppers etc…)

    • DC motors can be inexpensive but will vary in speed so you'll find your robot won't drive straight without compensating through programming. This can be accomplished using an Arduino Microprocessor.
    • Servos can be used to drive wheels but you'll want to get high speed continuous servos that are more costly. Most of the time you'll want a microprocessor to drive servos.
    • Stepper motors are very precise but can be noisy and bulky.
  • Chassis

    • That's how we roll! You need some wheels, treads, or legs, and a structure to put everything on. An inexpensive kit is This 4WD Robot Chassis
  • Micro-controller (Ex Arduino)

    • If you want more than two independently controlled DC motors, LED’s, servos, motor encoders, etc you will likely want to run these off an Arduino UNO or other similar board. Separating out data hungry tasks like streaming, TTS, and audio processing, on the Raspberry Pi and leaving movement controls for the micro-controller reduces the response time (lag or delay). A micro-controller, can respond extremely fast because it's not doing multiple complex things simultaneously. See Serial Interface Protocol for External Micro Controllers

Other Tools/Equipment

  • HDMI Monitor/TV + USB Keyboard

    • Don’t worry you won’t need these long, but they are reccomended for setting up your Raspberry Pi the first time. (You can set your Raspberry Pi up without them, it is just much more complicated)
  • PC or Mac to program and troubleshoot your robot.

  • Micro SD card reader.

  • Small Screwdrivers, Wire Cutters, Wire Strippers, Soldering Iron

  • Jumper wires

  • 2.5 mm Standoffs

  • Short Micro USB cord

  • Short USB A cord for connecting the Arduino Uno