Giladon-line » ubiach

iTeddy

Mon, 30 Jul 2007 01:18:40 +0000

The iTeddy is a media-playing teddy-bear for kiddies, funded by Dragon’s Den. The bear comes in two options; either as a standard MP3 player, or offering image and movie playback. The entry-level Â£35 MP3 player offers 128MB of storage and a USB2 connection to drag and drop files on to the player. The slightly more expensive Â£49 media player features a 2-inch colour LCD screen, a built-in rechargeable battery and 512MB of memory to store songs and videos.

Both teddy bears feature a speaker to share the music rather than having to rely on wearing headphones. Available in brown or white, the UK company behind the idea is hoping that tying in the bear with a website – iTeddy.co.uk – will help boost the appeal and offer additional content to download like movies, music and games. Although no content providers have been yet announced Imran Hakim the MD for iTeddy stated that a deal with Disney was in the works.

The company is also planning accessories such as a Webcap that features a webcam, iSpecs which features a digital camera and iBelt which would allow wireless communications with a PC to save having to connect and wires when transferring songs to and from the player. In a gimmicky move at a press conference earlier this week, taking advantage of its’ audio abilities, iTeDDy became the first toy to launch itself.

The UK-based critter is all set to launch today, and will be available in the Argos catalog for a respectable Â£59.99 ($123). The bear itself comes with a built-in LCD, integrated speakers, 512MB of internal memory, a rechargeable battery, detachable media player, an SD expansion slot, and a USB cable to load ‘er up.Â (source: engadget)

Bluetooth Research for Ubiach

Sun, 05 Nov 2006 22:49:32 +0000

Here is what we’re thinking of ordering: http://www.blueradios.com/BR-SC40A.pdf

But we’re still unsure about how to implement the audio PCM channel…. Trying to gather as much information as possible before we start hacking this chip.

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The following article is from mobileinfo

Bluetooth Technology

How Bluetooth Technology Works

“Connective convenience”

Bluetooth is a high-speed, low-power microwave wireless link technology, designed to connect phones, laptops, PDAs and other portable equipment together with little or no work by the user. Unlike infra-red, Bluetooth does not require line-of-sight positioning of connected units. The technology uses modifications of existing wireless LAN techniques but is most notable for its small size and low cost. The current prototype circuits are contained on a circuit board 0.9cm square, with a much smaller single chip version in development. The cost of the device is expected to fall very fast, from $20 initially to $5 in a year or two. It is envisioned that Bluetooth will be included within equipment rather than being an optional extra. When one Bluetooth product comes within range of another, (this can be set to between 10cm and 100m) they automatically exchange address and capability details. They can then establish a 1 megabit/s link (up to 2 Mbps in the second generation of the technology) with security and error correction, to use as required. The protocols will handle both voice and data, with a very flexible network topography.

This technology achieves its goal by embedding tiny, inexpensive, short-range transceivers into the electronic devices that are available today. The radio operates on the globally-available unlicensed radio band, 2.45 GHz (meaning there will be no hindrance for international travelers using Bluetooth-enabled equipment.), and supports data speeds of up to 721 Kbps, as well as three voice channels. The bluetooth modules can be either built into electronic devices or used as an adaptor. For instance in a PC they can be built in as a PC card or externally attached via the USB port.

Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to-point or multipoint. The maximum range is 10 meters but can be extended to 100 meters by increasing the power. Bluetooth devices are protected from radio interference by changing their frequencies arbitrarily upto a maximum of 1600 times a second, a technique known as frequency hopping. They also use three different but complimentary error correction schemes. Built-in encryption and verification is provided.

Moreover, Bluetooth devices won’t drain precious battery life. The Bluetooth specification targets power consumption of the device from a “hold” mode consuming 30 micro amps to the active transmitting range of 8-30 milliamps (or less than 1/10th of a watt). The radio chip consumers only 0.3mA in standby mode, which is less than 3 % of the power used by a standard mobile phone. The chips also have excellent power-saving features, as they will automatically shift to a low-power mode as soon as traffic volume lessens or stops.

Bluetooth devices are classified according to three different power classes, as shown in the following table.

Power Class

Maximum Output

Power

100 mW

(20 dBm)

2.5 mW

(4 dBm)

1 mW

(0 dBm)

But beyond untethering devices by replacing the cables, Bluetooth radio technology provides a universal bridge to existing data networks, a peripheral interface, and a mechanism to form small private ad hoc groupings of connected devices away from fixed network infrastructures. Designed to operate in a noisy radio frequency environment, the Bluetooth radio uses a fast acknowledgment and frequency hopping scheme to make the link robust. Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet. Compared with other systems operating in the same frequency band, the Bluetooth radio typically hops faster and uses shorter packets. This makes the Bluetooth radio more robust than other systems. Short packages and fast hopping also limit the impact of domestic and professional microwave ovens. Use of Forward Error Correction (FEC) limits the impact of random noise on long-distance links. The encoding is optimized for an uncoordinated environment.

Bluetooth guarantees security at the bit level. Authentication is controlled by the user by using a 128 bit key. Radio signals can be coded with 8 bits or anything upto 128 bits. The Bluetooth radio transmissions will conform to the safety standards required by the countries where the technology will be used with respect to the affects of radio transmissions on the human body. Emissions from Bluetooth enabled devices will be no greater than emissions from industry-standard cordless phones. The Bluetooth module will not interfere or cause harm to public or private telecommunications network.

The Bluetooth baseband protocol is a combination of circuit and packet switching. Slots can be reserved for synchronous packets. Each packet is transmitted in a different hop frequency. A packet nominally covers a single slot, but can be extended to cover up to five slots. Bluetooth can support an asynchronous data channel, up to three simultaneous synchronous voice channels, or a channel, which simultaneously supports asynchronous data and synchronous voice. It is thus possible to transfer the date asynchronously whilst at the same time talking synchronously at the same time. Each voice channel supports 64 kb/s synchronous (voice) link. The asynchronous channel can support an asymmetric link of maximally 721 kb/s in either direction while permitting 57.6 kb/s in the return direction, or a 432.6 kb/s symmetric link.

Modes of operation
An interesting aspect of the technology is the instant formation of networks once the bluetooth devices come in range to each other. A piconet is a collection of devices connected via Bluetooth technology in an ad hoc fashion. A Piconet can be a simple connection between two devices or more than two devices. Multiple independent and non-synchronized piconets can form a scatternet. Any of the devices in a piconet can also be a member of another by means of time multiplexing. i.e a device can be a part of more than one piconet by suitably sharing the time. The Bluetooth system supports both point-to-point and point-to-multi-point connections. When a device is connected to another device it is a point to point connection. If it is connected to more that one (upto 7 ) it is a point to multipoint connection. Several piconets can be established and linked together ad hoc, where each piconet is identified by a different frequency hopping sequence. All users participating on the same piconet are synchronized to this hopping sequence. If a device is connected to more than one piconet it communicates in each piconet using a different hopping sequence. A piconet starts with two connected devices, such as a portable PC and cellular phone, and may grow to eight connected devices. All Bluetooth devices are peer units and have identical implementations. However, when establishing a piconet, one unit will act as a master and the other(s) as slave(s) for the duration of the piconet connection. In a piconet there is a master unit whose clock and hopping sequence are used to synchronize all other devices in the piconet. All the other devices in a piconet that are not the master are slave units. A 3-bit MAC address is used to distinguish between units participating in the piconet. Devices synchronized to a piconet can enter power-saving modes called Sniff and hold mode, in which device activity is lowered. Also there can be parked units which are synchronized but do not have a MAC addresses. These parked units have a 8 bit address, therefore there can be a maximum of 256 parked devices.

Voice channels use either a 64 kbps log PCM or the Continuous Variable Slope Delta Modulation (CVSD) voice coding scheme, and never retransmit voice packets. The voice quality on the line interface should be better than or equal to the 64 kbps log PCM. The CVSD method was chosen for its robustness in handling dropped and damaged voice samples. Rising interference levels are experienced as increased background noise: even at bit error rates up 4%, the CVSD coded voice is quite audible.

Processing connection (PC) to Bluetooth (BlueSMIRF)

Mon, 23 Oct 2006 05:12:24 +0000

During the past week we’ve been working hard on getting the two to talk in a stable manner. There were many hurdles along the way, but we’ve managed to get a very stable connection between our processing app (running on a PC) and the BlueSMIRF chip from sparkfun, which we connected to a microchip PIC chip (we used the 18F252).

Step 1: Pairing the BlueSMIRF with the computer

In order to use the blueSMIRFS directly with the PC, they need to first plugged into power (ground, and connecting CTS and RTS). Then a connection needs to be established between the PC and the blueSMIRF (password is ‘default’). Later, it is possible to change the blueSMIRF’s name from the initial factory setting to whatever is wanted using microcode studio’s serial communicator.

Since my laptop doesn’t have a built in bluetooth device, I bought a Bluespoon USB dongle at Radioshack (a bit pricy, but is Bluetooth 2.0, and works very well – I found out that some USB Bluetooth dongles don’t work with the BlueSMIRF, so that’s something to consider). This step depends on the bluetooth software included on your computer, but basically at the end of this step, there should be an additional COM port in the hardware device manager (in the PC: right click ‘My Computer’->properties->hardware tab->device manager). When setting up the paired connection, it is usually possible to pick which COM port to use (when using the advanced setup mode). It is extremely important to remember the number of this port. This is the virtual communications port with which we can communicate directly to the specific BlueSMIRF chip from our computer.

Step 2: Setting up the BlueSMIRF

When setting up the configurations for the BlueSMIRF chip, we used the serial communicator provided by the Microcode Studio software (command F4 opens it). There, a direct connection to the BlueSMIRF can be made using the appropriate COM port (from the previous step). Here are some of the AT commands that we’ve used:

‘+++’ – to enter command mode

‘ATSN, ubiach1′ – change its name to ubiach1

‘ATMD’ – exit command mode

Here is a complete list of the blueradios AT command list, direct from the Faludi blog.

Step 3: Building the circuit

It is important to remember the the BlueSMIRF uses TTL logic while the PIC uses RS-232 for its’ serial communications. This will need to be taken into consideration when writing the PIC code (serin and serout commands between the two have to invert the logic – instead of using the 16864 option which we usually use for serial communications, we use 84 in order to implement the inverted logic connection with the BlueSMIRF: serout2 portc.6, 84, [inputData] ). Except for that, we used a 20Mhz clock, as well as a 3.3V regulator (5V can also be used). There are 3 status LEDs: The yellow blinks at startup, the green every iteration of the loop (when there’s no input data coming from the BlueSMIRF), and the red – toggled on and off using the processing code on the computer.

Step 4: The code

We implemented a simple call and response code (built on top of Tom Igoe’s PIC-processing code). There are some important things when writing the processing code, otherwise the communications won’t work. First of all, the appropriate COM port needs to be chosen from the generated list (the same COM port which was paired to the BlueSMIRF device). Sending data to the BlueSMIRF is done using the port.write() command. It is important to send a ‘\r’ when sending a byte to the BlueSMIRF (otherwise it crashes… at least on my computer). It is also important to take note of what you’re sending. The BlueSMIRF has a buffer, but the PIC doesn’t. So if it is more than one byte, a more complex method of communication between the PIC and the BlueSMIRF needs to be implemented (using CTS and RTS or interrupts). Since we only need to send and receive single bytes between the computer and the object that we’re building, it was enough for us to send single bytes (’char’ types). The next step would be to write a more complex bit of code, that would allow for proper transfer of any variable type between the two. Here is the sample code:

PIC Bluetooth Sample Code for the PIC.

Processing Sample Bluetooth Code for the Computer.

Next Step: audio

We want to figure out how to stream audio from the computer, through these BlueRadio chips (these are the bluetooth chips used on the BlueSMIRF) and into a physical object which we build. It is possible using more complex AT commands, in addition to other pins, which are not implemented using the BlueSMIRF. We might order this product from sparkfun and start playing around with that.