book

Building iPhone and iPad Electronic Projects

by Mike Westerfield

September 2013

Intermediate to advanced

332 pages

8h 30m

English

O'Reilly Media, Inc.

Read now

Unlock full access

Conventions Used in This BookUsing Code ExamplesSafari® Books OnlineHow to Contact UsAcknowledgmentsCredits
Your Own TricorderA Crash Course in techBASICtechBASIC SamplerRunning Your First ProgramCreating a ProgramThe Accelerometer
The GyroscopeRadians or Degrees?The MagnetometerFaster Sensor ResponseHeadingLocationYour Own Tricorder
The iPhone/iPad MagnetometerThe Earth’s Magnetic FieldUsing the iPhone or iPad as a Metal DetectorConverting the Magnetometer Sample into a Metal DetectorUsing the Metal DetectorFinding Out More
What Is HiJack?Building the SensorExternal Power for HiJackHello HiJackWhen Things Go WrongA Better HiJack ProgramFor More Information
Adding a Moisture Meter to the TricorderAssembling the Moisture MeterCalibrationCollecting the Calibration DataMoving Datafiles to and from techBASICUsing the Calibration DataBetter SoftwareThe Complete Moisture Meter Source
What Is Bluetooth Low Energy?The TI SensorTagWriting Bluetooth Low Energy ProgramsThe AccelerometerWhat’s an Accelerometer?Accessing the AccelerometerUsing the AccelerometerThe SourceThe BarometerAccessing the BarometerThe SourceThe GyroscopeAccessing the GyroscopeUsing the GyroscopeThe SourceThe MagnetometerAccessing the MagnetometerUsing the MagnetometerThe SourceThe Humidity Sensor (Hygrometer)Accessing the HygrometerThe SourceThe ThermometerAccessing the ThermometerUsing the ThermometerThe SourceFurther Explorations
A Bit of Rocket ScienceParts ListsST-1ST-2Other Items for Both RocketsWhy Use a SensorTag?ConstructionST-2: The iPhone/SensorTag RocketST-1: The SensorTag RocketThe Data Collection ProgramSensorTag 8G SoftwareFlight TipsEnginesParachutesFlight ConditionsPower Up!The DataAnalyzing the DataRocket Data AnalysisVelocity and AltitudeRotation and PressureWhat We FoundST-1 ResultsST-2 Results
Controlling a Truck with BLESelecting a TruckDisassemblyHacking the TruckThe H BridgeThe TI ChipWiring the Complete CircuitControlling the Arduino UnoInstalling ArduinoDownloading FirmataInstalling FirmataThe SoftwarePulse Width ModulationState enginesBack to the SoftwareStart Your Engines!
Bluetooth Low Energy Slave ModeBLE ChatSetting Up the ServicesUsing the Services

The Classic Game of PongThe Paddles GameThe Paddle SoftwareThe Paddles Console Software
Worldwide SensorsHTTP, FTP, and TCP/IPWiFlyThe CircuitEstablishing a Network ConnectionCommunication with TCP/IPA Simple Terminal ProgramWiFi ArduinoLoading Software onto the ArduinoThe CircuitCommunication Using the Terminal Program
Servos: They’re Where the Action IsThe Pololu Serial Servo ControllerThe CircuitHalloween HijinksThe SoftwareTake It for a SpinPush and Pull with ServosPomp and Circumstance

Content preview from Building iPhone and iPad Electronic Projects

Chapter 5. Creating a Moisture Meter with HiJack

Prerequisites: Read Chapter 1 and the end of Chapter 2 (the section on the techBASIC help system) if you need some help with techBASIC. Read Chapter 4 for general information about HiJack. In particular, iPads and late model iPhones need an external power supply for HiJack; see Chapter 4 for details.
Equipment: You will need an iPhone, iPod, or iPad running iOS 5 or later. You will also need a HiJack device from Seeed Studio, a Grove moisture meter (also available from Seeed Studio), and various common electronics parts like wires and resistors. See Table 5-1 for a complete parts list.
Software: You will need a copy of techBASIC or techBASIC Sampler.
What You Will Learn: This chapter uses HiJack, a device that supports an eight-bit A-D converter plugged into the headphone port, to build a plant moisture meter. This is a functioning example that shows how to use the technology introduced in Chapter 4 in a real-world sensor application.

Adding a Moisture Meter to the Tricorder

Back in Chapter 1 and Chapter 2, we explored the tricorder we all carry in our pocket. This project turns an iPhone or iPad into a quadcorder, hanging a HiJack A–D converter and sensor off the end and then using techBASIC to read it. We’re going to build a nifty moisture meter from off-the-shelf parts, as shown in Figure 5-1. Even the initial software is something you’ve seen before: we’ll start with the HiJack program from Figure 4-10 in ...