Learn Robotics Programming
The robot, reduced
At their core, robots can be simplified down to a motor, inputs, and a controller for processing or running code.
What are the two types of radiation that come from the sun?
Cosmic Radiation and Ultraviolet Radiation. Unlike cosmic radiation, UV radiation is lower in energy and is considered non-ionizing radiation (Cosmic Radiation is a form of Ionized Radiation.)
What is a CSI Camera Port?
The Camera Serial Interface camera port is a connector that allows the Raspberry Pi to connect to a Raspberry Pi camera module. Generic web cameras will not work as they commonly have only a USB connector.
What is DSI Display Port?
The DSI display port allows the Raspberry Pi to connect to a serial display similar to those used in tablets. Such display modules are available with touch controls and in common sizes such as 7 inches.
What robot is designed to function on a different planet?
The Mars Rover
The Raspbian goes best with the Raspberry Pi for what reason?
The Raspbian was specifically engineered for use in Raspberry Pi Computers. It was designed with the intent to make working with the Raspberry Pi easier.
What is the SFTP?
The Secure File Transfer Protocol. This lets you transfer files from a computer to a Pi. This lets you code on nice editors, then upload it to the Raspberry Pi. SFTP uses SSH to copy files to and from the Raspberry Pi over the network.
The Robotic Vacuum Cleaner
These devices are packed with sensors to detect walls, bag levels, and barrier zones, and avoid collisions.
Raspberry Pi Camera Module
(1.) Connects directly to a Raspberry Pi, this module can capture single images or video sequences. It can generate a lot of data quickly, for is one of the complications for robot vision. It is sensitive to lighting conditions.
Controller Modules 1
(1.) The Raspberry Pi 3B+ - A very powerful controller. It is the most capable of vidual processing from a camera. This fast and capable controller is closer to a phone in complexity. It's IO pins support many of the databus types, and digital IO, but for analog reading and some other IO functions, external controllers are needed. It is also a more expensive controller module and uses a lot of power.
What is a DC Motor?
(1.) The most common motor. This has the property of spinning in proportion to the amount of voltage running through it.
What is a bare DC motor?
(2.) A bare DC motor like this tends to spin a little too fast to be useful bare, and is very easily stopped. This is a DC Gear motor—a DC motor fitted with a gearbox, providing a reduction in speed and increase in mechanical advantage so it can move a larger load. Note that this gear motor is missing soldered leads! These types are most useful in the wheels of a robot.
Distance Sensor (The VL53LOX Time of Flight laser ranging sensor)
(2.) It uses an infrared laser to bounce off objects and detect how far away they are. This type of sensor sends a detected range directly to the controller. It can be sensitive to lighting conditions. The VL53L0X sensors use I2C, which means they send information as data directly to the Raspberry Pi, and can share their two communication pins with many other devices. I2C is good for when you have lots of sensors and outputs, and you are starting to run out of places to connect things. I2C sensors are handy, but they tend to be more expensive than sensors without this capability.
The Raspberry Pi Zero W
(2.) The Raspberry Pi Zero W is an inexpensive, lighter weight alternative to the full Raspberry Pi. It supports a camera and speakers. The Zero WH model includes the headers for IO too. It will perform speech and visual recognition, but will be slower at these than a Raspberry Pi 3. Their small size makes them an interesting option for a remote control pad though.
The HCSR04 Ultrasonic Distance Sensor
(3.) Another distance/ranging sensor which bounces sound pulses off objects instead. It's more sensitive to the types of material an object is made from and will fail to detect some surfaces, but is impervious to lighting conditions. The HC-SR04 requires the controller to trigger a pulse of sound, and then time the echo, which we will have to manage in our code for it. It has a far greater range than the VL53L0x laser sensor, and is far cheaper, but is also less sensitive at near distances.
The ESP8266 or NodeMCU
(3.) This controller has built-in Wi-Fi, and in this NodeMCU format can be programmed very easily from a PC using the same system as the Arduino, with Micropython or in Lua. It has plenty of IO pins, but only one is able to read analog signals. It supports many data bus types. It is somewhat faster and can hold larger programs than the Arduino. It is the cheapest controller in this lineup.
What is a servo motor (or servomechanism)?
(3.) This is the servo motor (or servomechanism). A controller sends a signal to this type of motor telling it what angular position to move to, with code working in degrees. The motor will attempt to reach and hold that position using it's own internal feedback loop, which means it can repeatably reach the same position. Servo motors are used in pan and tilt mechanisms to position sensors, robot arms, or other limbs and appendages, where the ease of positioning makes them more suitable than other motor types.
The Micro:bit
(4.) This controller module was released in 2015 for use in education, and is ideal for children. Its use in robotics requires a further adapter if you need more than the 3 IO pins shown, but it is still a pretty capable robot controller and comes with a nice built-in LED matrix. This can be programmed in Micropython, C, JavaScript, and a number of other languages.
Three line sensors
(4.) This is a set of three line sensors, that use light to detect transitions from light to dark. They can be adjusted to sense in different conditions. There are a few variations of these modules. They are a simpler sensor.
What is a Stepper Motor?
(4.) This is a stepper motor. These have coils powered in a sequence to allow the motor to step a certain number of degrees, so it can be used for very precise motions. Stepper motors tend to be slower and generate a lot of heat compared with DC motors or servo motors, but are most suitable for fine control, like that needed in 3D printers and high-end robot arms. They are also more expensive than the other types.
The Arduino Leonardo
(5.) Based around the Atmega 328 chip, and is a controller module that formed the basis of most of my robots around 2010-2012. The Arduino was important for the ease with which it could be connected to a PC via USB and programmed to immediately interact with devices attached to its IO pins. The Arduino is mostly programmed in the C++ language. In terms of IO, it has built-in pins to read analog devices, many digital pins, PWM output pins, and can be set up to handle most data buses. The Arduino is very flexible, but the processor is very simple; it is not capable of visual or speech processing tasks. The Arduino has a fairly low power consumption rate.
The fifth sensor
(5.) The fifth sensor is a pair of microphones with some tape to stick them crudely to a robot. These can connect directly to PCM pins on a Pi, but other microphones may need to be connected to electronics to process their signal further, into something the Raspberry Pi uses. There are arrays of four microphones or a single microphones that can be used, and in some contexts can detect the direction of sound as well.
Optical Interrupt Sensor
(6.) Passes infra-red light through a gap between two posts to detect whether something is between them, interrupting the beam. These are used with notched wheels to sense rotations, which can determine how far a robot has gone and introduce more accuracy into movements. Using an offset pair of these sensors with a wheel can encode the direction of the movement as well as its speed, and such an arrangement is known as an encoder. There are complete encoder assemblies available as sensors too, making it mechanically simpler to use them.
What are the three main elements to a robot?
1. A robot has inputs, and sensors to measure, and sample a property of its environment. 2. A robot has outputs, motors, lights, sounds, valves, heaters, or other types of output to alter it's environment. 3. A robot will use the data from its inputs to make autonomous decisions about how it controls the outputs.
What is a headless system?
A computer designed to be used from another computer via a network, for when keyboard, screen and mouse access to a device is inconvenient. Headless access is used for server systems and for building robots.
Display
Another helpful output device is a display—a simple light (or LED) to indicate the status of some part of the robot, or an array of LEDs, a display that can show some text, or a full graphical display like those found on a mobile phone.
What is the EQ radio
A device that can infer a person's emotions using wireless signals. It transmits an RF signal and analyzes its reflections off a person's body to recognize his emotional state (happy, sad, etc.)
What is a sensor?
A device that provides input to a robot, allowing it to sense its environment.
A Digital Signal (IO Pins)
A digital signal Some IO pins may be able to read varying levels, like that in the following image; these are analog input pins. If a sensor produces a changing resistance or continuous scale of values, then an analog pin may be the suitable place to connect it. Refer to the following diagram:
What is Git?
A popular form of source control, a way to keep a history of changes you've made to code. You can go back through changes, see what they were, restore older versions, and keep a commented log of why changes were made. Git also lets you store code in more than one location in case your hard drive fails. Git stores code and its history in repositories, or repos. In Git, you can make branches, copies of the whole set of code, to try ideas in parallel with your code and later merge those back to the main branch.
What is Ionizing?
A process by which electrons are stripped from atoms and molecules. This process can produce molecular changes that can lead to damage in biological tissue, including effects on DNA, the genetic material of living organisms. This process requires interaction with high levels of electromagnetic energy. Those types of electromagnetic radiation with enough energy to ionize biological material include X-radiation and gamma radiation. Therefore, X-rays and gamma rays are examples of ionizing radiation.
Why is analyzing the size of your components important?
A robotic AI mechanism is healthy when everything fits together in a way that looks natural. No matter the size of the hardware, nor the complexity of the inner-components, the number one goal is to help each piece fit perfectly.
What is the Raspberry Pi?
A series of small single-board computers developed in the United Kingdom by the Raspberry Pi Foundation in association with Broadcom. It is a family of single-board computers. Each SBC has different properties and capabilities.
What do all motors require?
All motors will require some sort of hardware so a microcontroller/computer like the Pi can drive them. This hardware allows the Pi to switch power hungry devices without destroying them. Don't connect DC motors, stepper motors, or solenoids directly to a Raspberry Pi!
What is special about the BigDog robot?
Also from Boston Dynamics, BigDog is a four legged robot, or quadruped, which is able to run and is one of the most stable four legged robots, and he's even capable of being pushed and shoved while walking in icy conditions and still remains stable.
What is an EMF?
An electromagnetic field is a classical field produced by accelerating electric charges. It is the field described by classical electrodynamics and is the classical counterpart to the quantized electromagnetic field tensor in quantum electrodynamics.
PIC Microcontroller
An honorable mention micro controller module is the PIC Microcontroller. These were used for hobby robotics long before any of the others, and have a thriving community since they are small, have low power consumption, and are extremely cheap.
What is a motor?
An output device that results in rotation when power is applied.
What is an actuator?
An output device, which is any device that creates movements from an electrical signal Examples: Solenoids, valves, and pneumatic rams. Motors are a subset of actuators too.
Can sensors detect emotions?
Automated emotion recognition is typically performed by measuring various human body parameters or electric impulses in the nervous system and analyzing their changes. The most popular techniques are electroencephalography, skin resistance measurements, blood pressure, heart rate, eye activity, and motion analysis.
Why does the kernel need to have similar controls when amplifying a headless robot over WiFi?
Because you are communicating between two different computers, so the Operating System downloaded to the control module needs to be somewhat similar to the computer being used to create the code and transfer the files.
Is there a device that can detect emotions?
CSAIL's new device, dubbed the EQ-Radio, extracts its data from wireless signals, making it more convenient and efficient than existing methods within the global emotion-detection space, which rely on on-body sensors or facial-recognition technology.
Chassis 1 2 and 3
Chassis 1 is 11 cm in and just about fits a controller in it, but is too tiny. This will make it hard to build your robot. Squeezing the controller, power, and all the sensors into this small space would need skill and experience beyond the scope of a first robot build. Chassis 2 is Armbot. This large robot is 33 cm by 30 cm, with an arm reach of another 300 mm. It needs eight AA batteries, big motors, and a big controller. These add to the expense and may cause issues around power handling for a new builder. It has lots of space, but issues around weight and rigidity. Armbot is one of my most expensive robots, excluding the cost of the arm! Chassis 3 in the preceding image will fit the Pi, batteries, and sensor, but without being large and bulky. It is around the right dimensions, being between 15-20 cm long and 10-15 cm wide. Those that have split levels might be great for this, but only one or two levels, as three or four will make a robot top heavy and may cause it to topple. This has enough space and is relatively easy to build.
Gas Central Heating Boiler
Contains sensors, pumps, and valves and uses feedback mechanisms to maintain the temperature of the house, water flow through heating, gas flow, and ensure that the pilow light stays lit.
Kismet
Created at MIT in the late 90s. A number of hobbyist robots are derived from it. It was groundbreaking at the time, using servo motors to drive face movements with the intention of mimicking human expressions. Following this robot is OhBot, an expensive hobbyist kit using servo motors, which can be linked with a Raspberry Pi, using voice recognition and facial camera processing to make a convincing display.
Dual Batteries
Dual batteries: The motors and the rest of the robot have completely separate sets of batteries, ensuring that their power is independent. Dual batteries are the most certain option to avoid any brownout, loss of power, or interference issues. This can take up a lot of space; however, a USB power bank is a simple and effective way to do this. Choose one with small outer case dimensions, but a high power rating, such as 10,000mAh, and an output of at least 2.1A.
Can RF signals hurt you?
Exposure to very high RF intensities can result in heating of biological tissue and an increase in body temperature. Tissue damage in humans could occur during exposure to high RF levels because of the body's inability to cope with or dissipate the excessive heat that could be generated.
What is special about the robot Atlas?
From Boston Dynamics, this robot is speedy on two legs and is capable of natural looking movement. It has a laser radar (LIDAR) array, which it uses to sense what is around it to plan and avoid collisions.
Who is Baxter?
From Rethink Robotics, Baxter is a safe robot to be around due to his sensory skills. He can sense a human and work around or pause for safety.
What is special about the Nao robot?
From Softbank Robotics, this rather cute 58 cm tall robot was designed as a learning and play robot for users to program. It has sensors to detect its motion, including if it is falling, and ultrasonic distance sensors to avoid bumps. Nao uses speakers and a microphone for voice processing. Nao includes multiple cameras to perform similar feats to the ASIMO.
What is special about Cog: The MIT project?
From the Massachusetts Institute of Technology, Cog attempted to be human-like in its movements and sensors.
Does the sun give off gamma rays?
Fusion in the core actually gives off high energy gamma rays. However, as the gamma ray photons make their arduous journey to the surface of the Sun, they are continuously absorbed by the solar plasma and re-emitted to lower frequencies. By the time they get to the surface, their frequencies are mostly only within the IR/visible light/UV spectrum.
How to protect the code
Secure File Transfer Protocol (SFTP), lets you transfer files from a computer to a Pi. This lets you write code on nice editors on your computer, then upload it to the Raspberry Pi. You can choose your editor and have the safety of more than one copy. SFTP uses SSH to copy files to and from the Raspberry Pi over the network. First, make yourself a folder on the PC to store your robot code in, then we can make a test file that will just print a bit of text and exit: (Look at how the book says to code it.)
What is the GPIO?
General Purpose Input/Output. Arguably the most important feature of the Raspberry Pi. These pins can be used in programs to read electrical signals from circuits as well as provide electrical signals for controlling circuits. Be very careful when using GPIO as they are easily damaged and use 3.3V logic. If you intend to control external devices that draw more than 20mA current, you should use a driver circuit (see 3.3 connecting I/O). This includes devices such as relays, inductors, and high brightness LEDs.
Testing The Components (Rhino)
I recommend test fitting before actually ordering parts. This helps me be more confident that they will fit and you know where they will roughly go. This step is optional, but it can save you time and money later.
Does the EEG produce ionizing radiation?
It does not change the brain's electrical activity. The EEG does not use any electrical shocks or radiation and does not have any side effects. It is safe at any age.
Motor Hat
It sits atop the Raspberry Pi
What is special about the robot Honda ASIMO?
It walks and talks a little like a human. ASIMO's two cameras perform object avoidance, and gestures and face recognition, and have a laser distance sensor to sense the floor. It can follow marks on the floor with infrared sensors. ASIMO is able to accept voice commands in English and Japanese.
What is Linux?
Linux® is an open source operating system (OS). An operating system is the software that directly manages a system's hardware and resources, like CPU, memory, and storage. The OS sits between applications and hardware and makes the connections between all of your software and the physical resources that do the work
Can non-ionizing radiation cause cancer?
Lower-energy, non-ionizing forms of radiation, such as visible light and the energy from cell phones, have not been found to cause cancer in people.
What is a Micro USB Power?
Micro Universal Serial Bus. Power to the Raspberry Pi can be provided using either a micro USB lead to the micro USB connector (recommended) or 5V can be directly fed into the 5V GPIO pin.
Why do motors need their own power system?
Motors need their own power system for a few reasons. First, they consume far more electrical power than most other components on the robot. They may require different voltages; it's not uncommon to have low voltage and high current capacity supplies for motors. The other reason that they need their own power system is that they can cause interference. They can pull enough power that other circuitry has brownouts and loses power long enough to get into an inconsistent or reset state, which would lead to SD card corruption on a Pi, and they can also introduce electrical noise to a power line as they are used, which could cause digital parts to misbehave.
What are some examples of non ionizing radiation?
Non-ionizing radiation includes visible, infrared, and ultraviolet light; microwaves; radio waves; and radiofrequency energy from cell phones. Most types of non-ionizing radiation have not been found to cause cancer.
Is non ionizing radiation harmful?
Non-ionizing radiation is not a significant health risk. In contrast, ionizing radiation has a higher frequency and shorter wavelength than non-ionizing radiation, and can be a serious health hazard: exposure to it can cause burns, radiation sickness, many kinds of cancer, and genetic damage.
The Washing Machine
Once the door is closed and the start button is pressed, it will output to lock the door. It then uses heaters, valves, and pumps to fill the drum with heated water, using sensor feedback to regulate the water level and temperature.
Pulse Width Modulation (PWM)
Pins are able to output a cycling digital waveform, allowing the code to select the frequency and how much time they are on for. The simple idea is that the length of ontime vs offtime in a cycle will change to vary an output signal and is often used to control the speed of motors.
What does the kernel do in a computer?
Provides basic services for all other parts of the OS
What is one place we get constant ionizing radiation?
Radiation from space is called cosmic radiation, which is constantly hitting the Earth. Our solar system's Sun and other stars in the galaxy emit a constant stream of cosmic radiation. In the United States, a person gets about 5% of their annual radiation exposure from cosmic radiation.
What is an RF signal?
Radio frequency is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around 20 kHz to around 300 GHz. A radio frequency (RF) signal refers to a wireless electromagnetic signal used as a form of communication.
SD Card corruption
SD card corruption is when the data on the SD card used to hold your code, Raspbian, and anything you've prepared on it is broken. Files become unreadable or the card becomes unusable. The information on the SD card can be permanently lost. If a Raspberry Pi unexpectedly loses power, the SD card can be in a poor state, causing data loss. A hot Pi can slowly bake an SD card, damaging it. Visual processing on a Pi is one way it can get hot. SD cards get damaged if something bad happens electrically to the Pi via the GPIO pins or its power supply. MicroSD cards are also very small and easily lost when not in the Pi.
What does the kernel do in the OS?
The core component of the Operating System. It provides the interfaces needed for users and applications to interact with the computer. It launches and manages applications. It manages the underlying system hardware devices.
Where does ionizing radiation begin to occur?
The dividing line between ionizing and non-ionizing radiation occurs in the ultraviolet part of the electromagnetic spectrum [shown in the illustration of the electromagnetic spectrum above]. Radiation in the ultraviolet band and at lower energies (to the left of ultraviolet) is called non-ionizing radiation, while at the higher energies to the right of the ultraviolet band is called ionizing radiation.
What are two areas where we find radiation?
The earth, and all living things on it, are constantly bombarded by radiation from space, similar to a steady drizzle of rain. Charged particles from the sun and stars interact with the earth's atmosphere and magnetic field to produce a shower of radiation, typically beta and gamma radiation. The dose from cosmic radiation varies in different parts of the world due to differences in elevation and to the effects of the earth's magnetic field.
What is the difference between Ionizing radiation and non ionizing radiation?
The energy levels associated with RF and microwave radiation, on the other hand, are not great enough to cause the ionization of atoms and molecules, and RF energy is, therefore, is a type of non-ionizing radiation. Other types of non-ionizing radiation include visible and infrared light. Often the term "radiation" is used, colloquially, to imply that ionizing radiation (radioactivity), such as that associated with nuclear power plants, is present. Ionizing radiation should not be confused with the lower-energy, non-ionizing radiation with respect to possible biological effects, since the mechanisms of action are quite different.
Where does the code run?
The main controller is where the code is run. It is the part that connects all the other components together and forms the basis of their interactions.
Path Following Behaviors and Robot Hardware Setup and Control
The path following behaviors will be able to remain the same if we keep the code. In other words, we can completely redesign the hardware of a machine and, assuming the setup and control is the same on the inside of the robot, the path following behaviors will follow through the exact same way. It simply does what it is programmed to do.
What are the two major power systems of a robot?
The power for all the digital parts, such as the Raspberry Pi and sensors, and then the power for the motors.
Does WiFi give off radiation?
The radiofrequency EMF given off by Wi-Fi is a type of non-ionizing radiation.
Simple IO Pins
The simplest IO pins are only able to output an on/off signal, or read an on/off signal, like in the following image; these are known as Digital IO pins. However, these can be programmed to perform more complicated tasks by detecting timing between signals, which is exactly the principle used in the HC-SR04 distance sensor. Refer to the following diagram:
What is the difference between the wave and the frequency?
The wavelength is the distance covered by one complete cycle of the electromagnetic wave, while the frequency is the number of electromagnetic waves passing a given point in one second. The frequency of an RF signal is usually expressed in terms of a unit called the "hertz" (abbreviated "Hz"). One Hz equals one cycle per second. One megahertz MHz equals one million cycles per second.
IO Pins
These are used for input and output from the controller; they give the controller its ability to connect to real-world sensors and motors. The number of IO pins on the controller can be a major limiting factor in what you can connect to a robot without using secondary controllers.
The Mars Rovers
These robots are designed to exist on a different planet, where there is no chance of human intervention if something goes wrong. They are robust by design. New Code can only be sent to a Mars rover via a remote connection as it is not practical to send up a person with a screen and keyboard. They are headless by design. They are designed with wheels instead of legs, as wheels are far better in making the robot stable. Each wheel has it's own motor. The wheels are arranged to provide maximum grip and stability to tackle the rocky terrain and reduced gravity on Mars.
HDMI/USB/Network
These slots are used to connect the Pi to an HDMI screen, USB devices such as mice and keyboards, and to an ethernet connection for internet access. However, the Raspberry Pi 3 comes with integrated Wi-Fi so there is often no need for the ethernet connector.
What is the range for the size of a robot arm?
They range from delicate robots for overturning eggs to colossal monsters moving shipping containers. They tend to use stepper and servo motors.
Different Layers
This means you're able to change one part of some code, without it making huge changes in another.
The Intellicart Following Robot
This robot is designated the job of working in a warehouse. It is capable of shifting pallets in storage complexes
What is a Micro SD Slot?
This slot is used to house the microSD card that holds the Raspberry Pi operating system. The microSD card does not come with the Pi. This SD card also holds all files, folders, documents, and pictures created by the user. It is essentially the hard drive of the computer.
How does the Raspbian get loaded onto the Raspberry Pi?
Through an SD card. Raspbian is the OS (It's actually the official operating system of the Raspberry Pi Foundation.) We start by downloading the Raspbian file into etcher. (Do not unzip the file) It's about 400 MB, and Etcher is a software that can link the Raspbian file to the SD card in a way that the Raspberry Pi can recognize. Raspbian is written with a command-line usage over a network in mind, it was designed for the headless system. Lastly, the Raspbian has software closest to the Raspberry Pi hardware, namely the kernel and drivers, which were made specifically for the Pi and Optimized for them.
Basic Robotic Kit Parts
Two wheels. Two encoder wheels. Two motors, with the wires. A castor wheel. The screws and brass standoffs to mount the castor wheel. I've replaced one set of screws with a nylon, non-conductive one. You should be able to do the same from the nylon standoff kit. In the middle is the chassis plate itself. On the right are plastic brackets to mount the motors. Your kit may have metal types, which work slightly differently and come with four extra screws. Finally, there are four screws and four nuts to mount the motors.
Smart Fans
Use sensors to detect room temperature, humidity, and air quality, then output through the fan speed and heating elements.
SD Card Mistakes
We all make mistakes. At those times, you'll want to go back and see what you've changed. If you've made a lot of changes, it may no longer be clear which things are different and what differences (if any) have broken the code. You can render your robot useless with bad configuration, such as the Pi not being on the network or booting anymore. An upgrade to system packages may go wrong and lead to code not working, or needing extensive changes to the code for it to work again.
Are we impacted by the sun's Cosmic Radiation?
Yes, but not heavily. At flight altitudes, passengers and crewmembers are exposed to higher levels of cosmic radiation.
Troubleshooting
You see:ImportError: No module named smbus You have missed the step installing the required packages. Ensure you have followed the apt-get install steps above. You see other errors Please go back and carefully check that you have typed and uploaded the code above to the Raspberry Pi. One or both sides are going backwards The motor wires are the wrong way. On the motor terminals only, swap the black and red wire. Refer to the How to wire up the motors and batteries photo for help. The light is on the controller, but one or both motors are not moving. Please ensure that both motors wires are firmly screwed into the terminals. Please see the steps in the Wiring in section. No light on the motor controller and no movement Please make sure you have attached both the battery wires into the correct terminals, as shown in the Independent power section. Please ensure that your batteries are well charged. Turning or veering Some veer will be expected. If it is sever, ensure that both motors' connections are good, and that neither the wheels nor the encoder disks are binding/caught on the chassis.
What is a solenoid?
a simple linear actuator using an electromagnetic coil with a metal core that is pulled or pushed away when power is applied to it. A common use of this type is in a doorbell mechanism. They are also used to operate valves on hydraulic or pneumatic actuators, which can create powerful motions like those seen in excavators and large industrial robotic arms.
Terrestrial Radiation
~Radioactive material found in: Soil, Water, Vegetation Radioactive material is also found throughout nature. It is in the soil, water, and vegetation. Low levels of uranium, thorium, and their decay products are found everywhere. Some of these materials are ingested with food and water, while others, such as radon, are inhaled. The dose from terrestrial sources also varies in different parts of the world. Locations with higher concentrations of uranium and thorium in their soil have higher dose levels. The major isotopes of concern for terrestrial radiation are uranium and the decay products of uranium, such as thorium, radium, and radon.
