 AnyWear consists of interface devices,
sensors,
and transducers designed to work with NeatTools
software for human-computer interaction applications. NeatTools is
available
as freeware.
click here for mac plug-in. click here for pc plug-in. |
TNG-3B is the latest in a succession of serial interface boxes that work with PCs. The earlier versions are TNG-1 and TNG-2 (pron. "Thing 1" and "Thing 2" , as in The Cat in the Hat by Dr. Seuss), which are respectively a) an interface device specialized for myoelectric (or electromyographic or EMG) signals and b) a general purpose interface device with four analog input channels. Note that TNG-1 and TNG-2 are not currently in production. Nor is the earlier prototype version, TNG-3, which is functionally similar to TNG-3B (but with a different wiring convention for stereo plugs for analog channels; and several other distinctions).
TNG-3B has 8 analog and 8 digital inputs and includes a DB9 serial-port connector for use on a PC. Together with appropriate sensors, transducers, and switches, it provides a flexible system for human-computer interface applications, notably for persons with severe disabilities. Kits of representative analog sensors and switches can be provided at modest cost upon request.
The heart of TNG-3B is a 40-pin Microchip PIC16C74A microcontroller integrated circuit, which sells for about $10 in single quantity (PIC stands for peripheral interface controller). Such microcontrollers (computers-on-a-chip) are widely used in consumer electronics (e.g. in stereo components and in their infrared remote controls); home appliances; digital thermostats; automotive electronics (e.g. fuel injection, electronic ignition, and antilock brakes); office and industrial automation; etc. The microcontroller in TNG-3B has been programmed in Microchip's RISC assembly language. Note that, while there are real concerns about certain embedded control systems, TNG-3B is fully Y2K compliant, because there is no absolute time measure used in its operation.
TNG-3B includes eight 1/8" stereo jacks (four on each side) with the following signal and power connections: sleeve (shell) = ground; ring = signal (0-5V range); and tip = 5V. The 5V power is derived from some of the serial-port handshaking lines using a method analogous to that used to power a serial mouse. The internal power budget requires that each input device should draw, on average, no more than about 1 mA, depending on the serial port on the PC being used. The 5V can be used to power passive (usually resistive) devices, subject to this limitation. Alternatively, one can power sensors separately (e.g. Hall Effect magnetic sensors which require extra circuitry and need more power than TNG-3 can offer). In this case, one should ensure that the analog signal to TNG-3B is confined to the 0–5V range. When resistive devices are used (potentiometers, CdS photocells, conductive-plastic pressure sensors, etc.), they are normally configured in a voltage divider with a 5k pullup resistor between the stereo plug signal line (ring) and Vcc (tip). A typical choice for a potentiometer (connected in a 2-wire arrangement as a variable resistor) is then 5k. For PCs with less powerful serial ports, such as notebook computers, one might wish to use 10k pullups instead, so as to limit the maximum current for a given channel to about 0.5 mA.
TNG-3B also includes an 8-channel digital input port. Access to the digital input lines is provided by eight mono jacks, six of which are along the bottom edge and two of which are on the sides near the lower corners. Normally, one connects switches (viz. single pole single throw [SPST]; normally open) to two-wire cables terminated with 3/32" mono plugs. The digital port (Port B) on the microcontroller (see below) includes internal weak pullups, so that no external pullup resistors are needed. A simple switch closure suffices for each line.
The communication between TNG-3B and the serial port of a PC occurs at 19.2 kbps. The data stream includes eight bytes for the analog channels, one additional byte for all eight digital inputs, and either of two separator (punctuation) bytes of 055h and 0AAh (85 and 170 decimal) that alternate on successive cycles (see properties of corresponding TNG3 module in NeatTools software). Consequently, the cycle period is approximately 5 ms, and the cycle rate is approximately 200 Hz.
TNG-3B has a DB-9 female jack at the top end panel. A 6-foot DB-9 extension cable is provided with TNG-3B. Make sure to keep them together. There is a serial-port test LED on the front that protrudes through the blue Lexan label. To test the activity of your serial port, press and hold the yellow pushbutton located to the right of the DB-9 jack on the top end panel, while observing the red LED. The LED is driven directly by code in the microcontroller chip. If the serial port is not active, then the power derived from the handshaking lines will be absent; thus the microcontroller will not operate and the LED will not illuminate when the test button is pressed. In NeatTools, the COM module must be enabled in order for the LED to illuminate. In case of a malfunction, first check that the baud rate in the COM module is set to 19,200 and that the correct port has been selected.
There is a rear label on TNG-3B to show that it has been tested to comply with FCC standards, and that it satisfies Canadian emission regulations as well. TNG-3B also is compliant with European emission standards, but has not been tested for noise immunity; therefore, TNG-3B is not available as yet for retail sale in Europe. The rear label also includes a serial number. Note that the rear label, which has a mirror finish is not rugged like the front label; so, it is possible to scratch the rear label. If you care about that, try to keep TNG-3B on smooth table surfaces, and in a protective bag during travel.
For ordering TNG-3B and related products, please visit http://www.sensyr.com.
