Most Popular Books by David Leithauser

This is a book of 75 logic puzzles in the form of murder mysteries. The format is to provide the description of the murder and the clues, then on the next page, provide the solution. Here is a fairly hard sample puzzle, taken from later in this book: Six men whose names are Larry Alberts, Fred Fox, Brian Davis, Jim Martin, John Stevenson, and Marty Graig were in an elevator together. Suddenly, the lights went out. When the lights came back on, Larry Alberts was found stabbed. Other detectives have investigated. They have questioned the suspects, the witnesses, and people who know the suspects. They have collected physical evidence (hair samples, fiber samples, etc.) from the crime scene. They have collected 14 clues, but have not been able to solve the crime. Therefore, they have called in the world''s greatest detective, YOU. You must now examine the clues and solve the murder. No two suspects have the same color shoes, hair color, color umbrella, color car, or weight. The suspect who was wearing white shoes has blond hair. John Stevenson was wearing red shoes. Brian Davis has red hair. The suspect who has black hair owns a black car. The suspect who owns a silver car has blond hair. The suspect who owns a blue car was wearing blue shoes. Fred Fox was wearing blue shoes. The suspect who was carrying an orange umbrella is not the one who has no hair. The suspect who was wearing brown shoes is not the one who owns an orange car. The suspect who was wearing white shoes weighs 170 pounds. Jim Martin weighs 220 pounds. Marty Graig was carrying a purple umbrella. The suspect who was wearing tan shoes has black hair. The murderer owns an orange car. There are 7 chapters in this book. Chapter 1 has REALLY easy puzzles just to get you started. Chapter 2 has slightly harder puzzles, and chapters 3 through 5 get progressively harder. Chapter 6 has puzzles of all five difficulty levels, mixed together randomly, so you do not know how hard the puzzles you are solving will be. This can actually be harder than solving a puzzle that you know is considered a hard one, because you do not know how complex your logic must be. In all, there are 75 of these logic puzzles in this book. In chapter 7, I added four cryptograms just to provide you with a change of pace.

This book is about controlling motors using Arduinos (called Genuinos outside the United States). I start out with simple direct current (DC) motors, covering turning them on and off, controlling their speed, and reversing direction. I then get into more complicated motors. I discuss two types of stepper motors, a type of precision motor that can be used for detailed control of devices like 3D printers, CNC routers, robot arms, etc. I also discuss servo motors, which are useful for setting positions, and brushless motors, which are good for high speeds like you might need for drone or model plane propellers, fans, model boat propellers, high-speed model cars, and any other application that requires high speeds. This book covers both electronics and programming, so are be electronic schematics and Arduino sketches. I assume that the reader is already familiar with the basics of Arduinos, such as how to install the IDE and load sketches, so I do not go into details on topics like that. I use Arduino Uno as the basis for designs in this book, but other models will work for most of the applications discussed in this book. In the last chapter, I provide several links to locations where you can download the sketches in this book to save you the trouble of typing them.

Global warming should not be controversial. It is not some new, untested theory. The science of global warming has been studied since 1856 and is well established. So why do some people claim that the science is not settled, or even totally deny it? The reason is that the way to combat global warming is to stop, or at least strongly reduce, our emissions of CO2 and other greenhouse gases, which means significantly reducing our use of fossil fuels like coal, oil, and natural gas. This would significantly cut into the profits of the very rich and powerful people who sell these fossil fuels, and they are not happy with that idea. They have therefore launched massive propaganda campaigns making false claims to convince the public that global warming and climate change are not happening at all, or that it is not caused by humans, or any other argument they can come up with to convince people that we should not switch to clean, renewable energy sources like solar or wind power. In this book, I will start out in the first chapter explaining the basics of how global warming and climate change work. In each of the following chapters, I will describe one misconception or deceptive claim about man-made global warming or climate change and explain why it is not valid. Each chapter will be titled with the claim that it disproves or explains. Note: To avoid any claims that I am writing this book for the money, I will donate 100% of the income from this book to charities that fight global warming. I will even match the first $1,000 per year from my own pocket.

OpenSCAD is a totally free program that takes a different approach than most 3D design programs. Instead of drawing the object by hand, it lets you describe it by telling it to create a shape like a sphere, cylinder, box, etc. and position it at a certain location. You can then add objects, alter them by doing things like stretching them, cutting away portions, and other operations that give you considerable control of the final product, all by simply writing what you want to do with the objects. This allows for considerable precision. You can view the object you are creating at any time to see how it is going so far.In this book, I will take you through the process of creating 3D models with OpenSCAD in a step by step manner that you will find easy to follow. I will concentrate on the aspects that I find most useful for generating 3D models suitable for 3D printing. I will not get into aspects of OpenSCAD designed to make pictures or 3D movies, such as coloring objects or animation, unless they have some use as a modeling design tool.I will end the book with a series of chapters called the project section that describe how to make a variety of actual objects that you can use. These give you examples of how to put together the techniques I have discussed in the earlier chapters and also provide useful components like connectors and moving parts that you can incorporate in your own projects.

Although you can buy a wide range of shields for Arduino, making your own will not only save you money, it will give you more flexibility and control of your designs. This book shows you how to connect sensors and other devices to your Arduino inputs and outputs using basic components like resistors, diodes, transistors, and op-amps. All of the components used in this book can be purchased cheaply on eBay or Amazon, as well as other electronics outlets. Dozens of generalized circuits that you can modify for your needs are shown, complete with the necessary equations to select the proper component values for your needs. Heavy emphasis is placed on connecting sensors not originally designed for Arduinos to the analog inputs, as well as connecting signals other than 5 volts to digital inputs. Connecting heavy loads to the outputs is also discussed. Protecting your Arduino is the topic of one chapter, and specific tips for doing this are given for individual circuits throughout the book. This is a practical guide to designing electronic circuits to connect to your Arduino. Although it will be helpful if you already have a basic knowledge of electronics, this book provides a basic background, like reading schematics and choosing components.

This book is about connecting sensors and radio transceivers to an Arduino so that you can monitor the sensor readings from a distance. You can put the Arduino sensor package miles away from the receiving station, in your front or back yard, or even in your home like your basement or attic. Although the techniques described in this book will work with any type of sensor input, the book will focus on sensors that detect potentially dangerous or disruptive conditions. These will include intruders, fires, flammable gas leaks and other toxic gases like pollution, power failures, floods (including minor "floods" like a pipe bursting), and other hazards. For the radio communications, we will use the nRF24L01 transceiver chip. This inexpensive chip (usually around $1.00 on EBay) interfaces easily with the Arduino and can both transmit and receive data. It has an advertised range of 100 meters (about 328 feet) for the basic unit, although in actual practice it may be closer to 30 meters (about 98 feet). However, with an optional antenna the range is reported to be 1,000 meters (1 km, about .6 miles). In the first five chapters, I explain the hardware and software aspects of this handy transceiver, enabling you to set up the communications. I even explain how to set up repeater transmitters that can relay the signal from locations beyond the 1 km range. In the chapters after these five chapters, I discuss attaching and operating various analog and digital sensors, explaining how to set them up and integrate them into the transmission software. The chapters will be divided by hazards you can monitor, not specific sensors, so one chapter may include several different types of sensors that can be used to detect the same hazard.