Mote Specifications
From Seamonster
Motes ("Telos-B")
- Koala: 2008--2009 SEAMONSTER follows in the muddy footprints of Johns Hopkins Life-Under-Your-Feet soil ecology program
- Koala LUYF: The main trunk of the evolutionary tree of Koala.
- Motes, Mote Specifications
- Field Motes, Mote Sensor Cable, Mote Sensor Calibration, Mote Float Boat
- Managed deployment report
Related
- Technical, Architecture, Sensors, Microservers
- Future directions: Mote Service Board
- Circa 2007 TinyOS-1 pages (pre-Koala): 2007 TinyOS
- Circa 2007 TelosB mote pages: Search on "2007 Mote".
Contents |
Introduction
A mote is basically a microprocessor glued to a radio. We've begun with Moteiv Corporation's Tmote Sky devices and the basics of working with these devices are documented on this page. Notes on learning to program Tmotes are here.
Simple Demonstration
Suppose you have two Tmotes and a computer with the demo environment set up (including Cygwin). To demonstrate a simple temperature sensor turbidity sensor you would go to this internal link and follow the steps.
Operational Requirements
Seamonster will make use of essentially two types of motes: Field motes and Base Station Motes. The latter may reside inside the microserver case, or may be adjacent and connected via external USB port. They act as the anchor point of the mote subnet and therefore the interface between that subnet and the microserver network.
Base Station Motes must:
- Pick up returning subnet data packets and transfer them to the microserver.
- Relay queries/messages from the microserver to the subnet.
- Operate off the microserver power supply or their own independent supply.
Field Motes must:
- Hold a unique subnet identification tag
- Accept configuration directives that change operational parameters.
- Operate in low-power / normal-power modes according to a schedule (modifiable).
- Connect to one or more sensors and obtain data values (scheduled, modifiable).
- Convert these data values to data packets and send them to the local Base Station Mote.
- Suffer no confusion in the case that subnets overlap in radio range.
Tmote Sky specifications
Interface Port Pinout
Based on the above diagram the peripheral connector port pins (sorry about this) are laid out like this:
10 pin expansion connector 6 pin expansion connector U2 U28 .......................... ............... . 9 7 5 3 1 . . 5 3 1 . . . . . . 10 8 6 4 2 . . 6 4 2 . .......................... ...............
Abbreviated listing:
- U2: 1 Vcc (That's a 3V supply)
- U2: 2 UART RX
- U2: 3 ADC0
- U2: 4 UART TX
- U2: 5 ADC1
- U2: 6 I2C Clock MX:GIO4
- U2: 7 ADC2
- U2: 8 I2C Data MX:GIO5
- U2: 9 Gd
- U2: 10 ADC3
- U28: 1 ADC6
- U28: 2 ADC7
- U28: 3 GIO2
- U28: 4 GIO3
- U28: 5 Interrupt
- U28: 6 Reset
Modifications for Field Use
This sub-section explains how to get started in moving a Mote from its "out of the box" state to something that can be placed in the field for extended periods of time. The continuation of this train of thought is located in this sub-section of the dedicated Field Motes page.
Here is the Tmote Sky unit as it arrives in the mail (with optional sensors included: T/RH, PAR, TSR at bottom center of the printed circuit (PC) board in this photo).
Referring to the photos above and below, from the "out of the box" state we make the following solder-based modifications:
- De-solder and remove the (2 x AA) battery clip from the back of the mote (above: black plastic visible at bottom).
- Attach longer power leads (below: black and orange wires at right)
- Attach a 10-pin header to the U2 peripheral port (above: lower left, below: upper left).
- Attach a smaller 6-pin header to the U28 peripheral port (above/below: to the right of U2).
- Attach an SMA-type antenna connector (above: upper left, below: lower left, see five (box plus center) solder pins).
- The antenna selector/jumper is moved to direct the RF signal to the SMA connector, see note below.
Note: Moving the antenna jumper is a fine (tricky) operation that is is documented in the Moteiv literature. We'll document it carefully when we get a chance but it will require a better photo of the SMA-pad side of the board. The short of it is this: A little tiny 0-ohm resistor (i.e. effectively a piece of wire) sits on the top side of the board near the SMA pad. In the top photo in this section (the one showing the top of the board) it is just above the 'i' in 'Moteiv' printed at the left edge of the PC board. This little resistor is clearly connecting two circuit board traces: A center trace "antenna feed" and a trace that goes to the narrow edge of the PC board where Moteiv is written. There this trace acts as an "indoors" antenna. This resistor must be heated on both sides using two soldering irons and moved sideways so that it now connects the center trace to the SMA trace (instead of to the edge-of-board trace). The SMA trace goes to the center pin of the 5-pin SMA pad, i.e. the one in the center of the square made by the other four pins.
General Tmote Sky Device Information
Moteiv corporation makes Tmote Sky mote-devices available for about $100 apiece with a simple sensor package installed. The product page with document links is here (see below). I grabbed some key info from the data sheet to get the basics across, as follows:
- Radio is 2.4GHz ISM-band carrier, rate is 250kbps with about 100 meters range
- Processor includes 48k Flash and 10k RAM; the TI MSP430 8MHz microprocessor
- Integrated sensors include relative humidity / temperature / 2 light sensors
- Device features a very convenient USB port for data collection and easy programming
- Power supply: 3 volts; typically 2 AA batteries (say 3 amp-hours)
- Power Consumption (radio on, MCU on): 23 milliamps (130 hours)
- Power Consumption (radio off, MCU on): 2 milliamps (62 days)
- Power Consumption (radio off, MCU standby): 20 microamps (17 years)
- Physical size, no batteries: Approx 3cm x 7cm x 0.5cm.
- Physical size, with batteries: Approx 3cm x 7cm x 2cm.
- 16-pin port includes: UART, I2C, 6 ADC channels, 4 GPIO lines, Reset and Interrupt
More specs are available at Moteiv's site.
