Section 1 – Group Member Responsibilities
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- Section 2 - Research Section 2.1 – Bluetooth
- Section 2.2 – iPhone Gamepad Control
- Section 2.3 - Bluetooth Controller Capabilities on an Android Device
- Section 2.4 - Inductive Charging General
- Inductive vs. Conductive Charging: Conductive Charging
- Primary Inductive Structure
- Secondary Inductive Coil
- Section 2.5 – Handheld Ergonomics General
- Usability of holding
| Christopher Delgado
Richard Prego Matthew Neuteboom Ron Puertollano Timothy Pirog February 24, 2012 Section 1 – Group Member Responsibilities This report is comprised of research information related to the design of a gamepad add on for smartphones. The summary of assignments for each group member is as follows:
Section 2 - Research Section 2.1 – Bluetooth Bluetooth is a specification for the use of low-power radio communications to act as replacement for wires/cables in order to wirelessly connect computers, phones and other network devices. It has a range of about 10 meters, limiting its usage to devices located within a single room or vehicle and provides a throughput of about 1Mbps. Bluetooth operates in the 2.4 GHz ISM band (the Industrial-Scientific-Medical band). This frequency band is license-free and open to any radio system in the world. Since the ISM band is open to other devices, Bluetooth avoids interference by employing an adaptive scheme that finds an unused part of the spectrum. Bluetooth radios use a frequency-hop spread spectrum which divides the frequency band into several hop channels. During a connection, radio transceivers hop from one channel to another in a pseudo-random manner. This results in low cost, narrowband transceivers with maximum immunity to interference. [Haartsen] Each Bluetooth channel is divided into 625 μs intervals (called slots) where a different hop frequency is used for each slot. One packet can be transmitted per slot. Subsequent slots are alternately used for transmitting and receiving. Packets exchanged between master and slave have a fixed format of a 72-bit access code followed by a 54 bit Packet Head and then the payload (0-2745 bits). The access code is used for packet identification, synchronization and offset compensation and is resistant to interference. The header contains control information such as the MAC address and is protected by a one-third rate forward-error-correction code. For higher data rates, packets can cover multiple slots. Two or more Bluetooth devices within range of each other set up ad hoc connections, meaning that they communicate in a peer-to-peer fashion without involving central access points. Devices sharing the same channel form a piconet, with one device acting as a master which controls traffic on the piconet and the others as slaves. Every piconet has a unique set of parameters which create unique channels. Bluetooth is similar to WiFi (IEEE 802.11) in that both operate in the 2.4 GHz RF range, both utilize Frequency Hopping Spread-Spectrum technologies, both provide "discovery" services to find peers, and both provide authentication and encryption security services. However, Bluetooth has a smaller scope than WiFi, which allows for having concentric network domains as you can have a personal area network (PAN) within a local area network (LAN). [High Wire Acts, Without a Wire]
The iPhone/iPad software, iOS, does not natively support Bluetooth gamepads. However, iOS does support Bluetooth keyboards. There are some Bluetooth gamepad accessories for iOS currently on the market, which use keyboard-based keybindings for the controls. Essentially, the gamepad acts like a Bluetooth keyboard as far as the iPhone or iPad is concerned. One of the first iOS Bluetooth game control devices was the iCade, an arcade cabinet that a user can place an iPad in to control arcade games. The iCade uses keybindings for different keypresses, which are interpreted by the game being played. There are currently about a dozen games that support the iCade for control. A similar iPhone gamepad, the iControlPad, uses the same keybindings as the iCade, and is supported by the same games. On a non-jailbroken iPhone, the iCade and iControlPad can only be used with the games that support it. Jailbroken iOS devices can utilize an app called Blutrol, which allows the user to map the controls on a gamepad to the in-game controls for any game. This app truly allows any iOS game to be controlled by a Bluetooth controller. Our project could use the same keybindings as the iCade and iControlPad. The controller would therefore be compatible by default with the same dozen apps that already support gamepad control, and we could also make use of the Blutrol app to extend the functionality of the control pad to any other iOS games as well. Currently, Blutrol supports only directional pads (D-pads) for directional control. We hope to include an analog joystick on our controller, so we would have to either find a way to emulate a D-pad with an analog stick, or develop our own protocol for the analog stick, which game developers could develop games for. If the product takes off and sells well, it would be in game developers' interests to develop games for our product.
The Android platform comes with built-in Bluetooth APIs (application programming interfaces) that allow applications to wirelessly connect to other Bluetooth devices. All of the Bluetooth APIs are available in the android.bluetooth package. A BluetoothAdapter class represents the local Bluetooth adapter (Bluetooth radio). It is the entry-point for all Bluetooth interaction. It discovers other Bluetooth devices and can query from a list of paired devices. Bluetooth devices are paired to a phone using a known MAC address. A Bluetooth socket exchanges data with the device via InputStream and OutputStream.[1] Bluetooth devices can be assigned classes. One of the classes listed is ‘TOY_CONTROLLER.’ [2] This can used to prevent the phone from searching for other Bluetooth devices (like other Bluetooth-enabled phones) in the local area while using our app. High quality audio can be streamed from one device to another over a Bluetooth connection. An app on the Android market currently performs a similar task by connecting a Sixaxis PS3 to the phone via Bluetooth. The app, simply called the Sixaxis Controller app, works on Honeycomb 3.1. It requires root access. It can run on a stock ROM. One possible solution to implement a controller would be to masquerade as a Sixaxis controller. This solution would provide a convenient way to implement all of our button requirements since the Sixaxis controller has a direction pad, four face buttons, two shoulder buttons, and two analog sticks.[3] The biggest competitor currently in the Android game pad market is the Gametel Bluetooth Controller. It already uses Bluetooth to connect to the Android device. The controller is attached to the bottom of the phone, and the phone sits inside a sliding gripper on the top of the controller. According to a Slashgear article, its battery is large enough to last a cross-country plane ride. It’s charged by the phone’s micro-USB cord. However, it lacks an analog stick and only has four buttons. Games also require set up in order to use it. [4] The shoulder buttons are hard to reach with the phone attached.[5] It runs on smartphones 2.1 or later. As of January 8, 2012, it is only sold through the UK and other European markets. [1] “Bluetooth’ [2] “BluetoothClass.Device” [3] "How to Connect PS3 DualShock 3 Controller to Android Phone or Tablet." [4] “Slashgear” [5] “Gametel Bluetooth Controller for Android and IOS Hands-on."
Normally, chargers that depended on the contact between metal surfaces lost efficiency due to heat dissipation. Inductive charging is the charging between two objects through electromagnetic fields. A converter transforms AC into DC, then the inverter again transforms the DC into ACE for driving inductive core of the primary inductive coil (Charging Platform). In the secondary inductive coils (Device to be Charged), the inductive core picks up power from primary and the power is then rectified in order to charge the lithium battery.
Primary Inductive Structure: Under constant length, inductive coils must produce enough flux and low leakage of flux to operate efficiently. There are three commonly used inductive structures: Type 1: a cylindrical beam, Type E, a E shaped object with a cylindrical center, and a Pot Type which resembles a pot with a indented middle around the center. Type 1's inductive structure provides poor magnetic field closeness and large leakage flux. This results in difficulties in creating magnetic circuit and a decrease in overall coupling coefficient. Type E's inductive structure has better magnetic field closeness and better coupling effects, but loses out in its large size and susceptibility to horizontal displacement. This type of inductive structure does well for larger and constant loads. Pot Type inductive structure has a more compact design thus magnetic circuits become easily created and lower leakage flux is produced opposed to type E. Gamepad add-on's best interest is to use Type 1 or Pot Type inductive charging due to constant movement. Secondary Inductive Coil: Designs of Secondary Inductive Coils are flat. Control Scheme: When the Secondary Inductive Coil is removed from the charging platform, the quality factor of the charging platform increases. This results in the increase of primary voltage. Removal of the Secondary Coils, also causes unnecessary power consumption and heating of the coils. PIC165876A Microprocessor is the controller circuit of inductive charging systems. When the voltage level reaches the threshold of the microprocessor, the microprocessor reduces the consumption of power by sending low-level signals to switch off the optocoupler. When the the coils are reconnected, voltage levels change and the microprocessor will in-turn turn the coupler on. Charging Circuit: The three steps of the charging process is the pre-charge mode, constant current mode, and constant voltage mode. The integrated chip, BQ2057, developed by TI is utilized to implement charging circuits. At the pre-charge mode, BQ2057 charges the battery with constant current if the voltage of the battery is too low. In due course, the voltage of the battery will gradually increase to the default value. When the voltage is at optimal levels, BQ2057 switches to constant current mode and charges with current of default value. When charging is completed, constant voltage mode occurs and constant voltage is used to charge the battery as the charging current diminishes over time. Section 2.5 – Handheld Ergonomics General: For smartphones whether they are Apple, Android or Windows, and the size, dimensions, and shape is different for each of them. Smartphone’s still keep about the same general design, a thin rectangular device which has a screen on the front in-between a mic, which is on top, and some button(s) which are on the bottom of the front face. On the back face there is usually a camera. An add-on for a gamepad needs to fit to the form factor and still allow about the same portability as the device without the accessory. Key requirements: The definition of a portable device is on that can be carried for 10 minutes without having to rest: For single handed carrying < 4.4 kg. For use held away from the body < 2.3 kg if manipulated with precision < 400 g Usability of holding: There are several things we must look at such as room for finger grips or rounded edges and texture help for the hands. Secondary features to consider: The battery life of all handhelds can make a significant problem to the ergonomics of the device because it can cause bumps and humps which can interfere with the persons fingers and make it uncomfortable. The other problems are the plugs and cables need to be easy to access and can still work well with the hand of they are plugged in.
The material which it is made out of must be able to handle temperature changes, drops, and be resistant to environmental hazards. Each of these components can change the material which the handheld is made of and can then alter the ergonomics of the device. Feedback from the device is generally a good things and vibration lets the person know that it is working correctly or can make the user more involved with the device.
Handheld devices have been around for a long time but when ever using a new or different design a test with humans using it for a long time determines of whether it will be successful or not as a portable device. Everything has to work together well from comfort in hand to comfort in the pocket all these things must be taken into perspective. Section 3 - References "Bluetooth." Web. 24 Feb. 2012. "BluetoothClass.Device." Web. 24 Feb. 2012. "Blutrol." Web. 24 Feb. 2012. Boxer, Steve. "PS Vita: The inside Story." The Guardian. Guardian News and Media, 25 Sept. 0042. Web. 24 Feb. 2012. "Charging by Electrostatic Induction." Oswego City School District Regents Exam Prep Center. Web. 24 Feb. 2012. "Ergonomics of Hand-held Devices for Industrial Use." Process Contracting Home Page. Web. 24 Feb. 2012. "Gametel Bluetooth Controller for Android and IOS Hands-on." Engadget. Web. 24 Feb. 2012. Haartsen, Jaap. "BLUETOOTH—The Universal Radio Interface for Ad Hoc, Wireless Connectivity." Web. "High Wire Acts, Without a Wire - A Bluetooth Primer." Media Net Link. Web. 24 Feb. 2012. "How Can an Electric Toothbrush Recharge Its Batteries When There Are No Metal Contacts between the Toothbrush and the Base?" HowStuffWorks. Web. 24 Feb. 2012. "How to Connect PS3 DualShock 3 Controller to Android Phone or Tablet." How to Connect PS3 Sixaxis / DualShock 3 Controller to Android Phone or Tablet with Sixaxis Controller [Tutorial. Web. 24 Feb. 2012. Hung-Yu Shen; Jia-You Lee; Tsung-Wen Chang; , "Study of contactless inductive charging platform with core array structure for portable products," Consumer Electronics, Communications and Networks (CECNet), 2011 International Conference on , vol., no., pp.756-759, 16-18 April 2011
"ICade Developers Resource." ThinkGeek. Web. 24 Feb. 2012. "ICade Protocol Support." Retrode Community Forum. Web. 24 Feb. 2012. "IControlPad - Bluetooth Gaming Controls for Your Smartphone." IControlPad. Web. 24 Feb. 2012. "IControlPad." Wikipedia. Wikimedia Foundation, 23 Feb. 2012. Web. 24 Feb. 2012. "SlashGear." Gametel Bluetooth Controller Makes Android Gaming a Breeze -. Web. 24 Feb. 2012. Directory: ~hman -> ECE322S12 ~hman -> Bluetooth connected Gamepad for Android Phones By: Adam Chodaba ECE322S12 -> Homework 1: Initial Idea (Due: Jan. 27) Download 35.37 Kb. Share with your friends:
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