Demo Abstract: Introducing the MagoNode Platform

Ugo Maria Colesanti†, Antonio Lo Russo†, Mario Paoli?, Chiara Petrioli?, AndreaVitaletti†

†Dipartimento di Ingegneria Informatica, Automatica e Gestionale, Sapienza Università di Roma?Dipartimento di Informatica, Sapienza Università di Roma

{colesanti,lorusso,vitaletti}@dis.uniroma1.it , {paoli,petrioli}@di.uniroma1.it

ABSTRACTThe purpose of this demo is to introduce a new low-powerwireless device for Wireless Sensor Networks (WSN) oper-ating in the ISM 2.4Ghz band: the MagoNode. Thanks to ahighly efficient RF front-end, that extends the radio rangeand increases link reliability, the MagoNode features out-standing RF performance, still containing energy consump-tion. The platform has been designed at the Department ofComputer, Control, and Management Engineering AntonioRuberti of the University of Rome La Sapienza in collabo-ration with the spin-off WSense [1].

Categories and Subject DescriptorsC.2.1 [Computer-Communication Networks]: NetworkArchitecture and Design—Wireless communication

General TermsWireless Sensor Networks

KeywordsMagoNode, hardware platform, wireless sensor networks

1. INTRODUCTIONMost of the common hardware platforms dedicated to

Wireless Sensor Networks (WSN) use 802.15.4 complianttransceivers operating in the ISM 2.4 GHz band [2]. Theadvantages of using a world-wide available band such as2.4GHz band are a higher data rates w.r.t. other ISM bands(433Mhz,868/915MHz), almost no restrictions related to theduty cycle [3, 4] and ZigBee compliance [5]. Of course,those advantages come together with some disadvantages,like lower transceiver sensibility and higher propagation lossesdue to the higher transmission frequency. In several scenar-ios the limited radio range of 802.15.4 transceivers requiresthe presence of several relay nodes. Based on our experi-ence with structural health monitoring scenarios, there are

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Figure 1: The MagoNode OEM platform.

several cases in which the increase of relay nodes over thetotal number becomes an issue in terms of hardware anddeployment costs as much as waste of energy. To overcomethis issue, some recent hardware solutions for WSNs havestarted to propose built-in RF front-ends [6, 7]. An RFfront-end is a combination of a Power Amplifier (PA) and aLow Noise Amplifier (LNA) that enhance the transmissionand the reception of the transceiver, at the expense of an en-ergy cost overhead. However, the constantly lowering powerconsumption of RF front-ends makes this kind of solutionmore and more convenient.

2. PLATFORM DESIGNDuring the design of the MagoNode platform several as-

pects have been taken into account. First of all we lookedtoward a cheap, low-power microcontroller and transceiverbundle, with software support for existing WSN operat-ing systems (TinyOS, Contiki [8]). We chose Atmel’s At-mega128RFA1 (RFA1) featuring 8-bit, 16MHz System-On-Chip (SoC), with an integrated low-power transceiver 802.15.4that is supported by Atmel’s BitCloud ZigBee stack, TinyOSand Contiki. We based the RF front-end selection on twofundamentals observations: first of all, we expect idle listen-ing to represent the predominant energy cost on a wirelessnode, hence, it becomes important to pay as little RX over-head as possible when adding an RF front-end. Secondly,local regulations considerably limit the maximum outputpower: ETSI EN 300 328 V1.8.1 [3] in Europe limits maxi-mum output power (Pout) to approximately +10dBm, whileFCC CFR45 [4] in North America limits it to +18-20dBm[9, 10]. Based on these statements, we decided to chosetwo interchangeable RF front-end (i.e., that share the samefootprint) for our platform: the CC2590 (Pout equals to+14dBm) and CC2591 (Pout equals to +22dBm) RF front-end by Texas Instruments. This choice represents the opti-mal solution in terms of trade-off between Pout and energy

Figure 2: Consumption comparison: MagoNode vs amplified motes (left) and MagoNode vs unamplifiedmotes (right).

consumption. Indeed, it makes nonsense to use a +20dBmdesigned front-end in Europe while it would be limiting touse a +10dBm designed front-end in North America. TheMagoNode platform is designed as a 4-layer OEM board, i.e.,a castellated PCB solderable on bigger application-specificboard (Figure 1).

3. COMPARISON WITH OTHER PLATFORMSWe evaluated both versions of the MagoNode, i.e., the

European (CC2590) version and North American (CC2591)one, with similar state-of-art amplified wireless nodes: At-mel’s ZigBit [6] and Dresden Elektronik deRFMega [7]. Inparticular we compared the current consumption of eachplatform with respect to Transmission (TX), Reception (RX)and Idle Listening (IDLE) radio states. A similar compari-son has also been performed between the European versionof the MagoNode and most commonly available unampli-fied motes (Figure 2). Actually, we want to demonstratenot only the competitiveness of our solution compared toother amplified devices, but also that the energy overheadintroduced by the MagoNode is low enough to get comparedwith unamplified motes. As we can see from Figure 2 (left)the MagoNode overwhelms the performance of the ampli-fied motes with which it was compared both in TX, RX andIDLE. On the other side, as we can see from Figure 2 (right),the MagoNode drains more energy in TX than unamplifiedmotes with which it was compared. This is due to the RFfront-end featured by our platform. Things change in RXand IDLE where the MagoNode has lower current consump-tion than IRIS and TelosB, but it cannot beat the EK1 sinceit is similar to a non-amplified version of the MagoNode (i.e.,it features the same MCU).

4. BOARDSWe integrated the MagoNode in three different boards de-

sign. The first one is a common academic-like board, namelyMNA-Board (Figure 3), featuring 2xAA battery holder, apower switch, three debug leds, an RP-SMA connector, a51 pin Hirose expansion connector and, optionally, 2MBflash chip. This board allows quick prototyping and debug-ging as much as easy deployment. The second board is anapplication-specific sensor-board which acts as an interfacefor 4-20mA current-loop sensors (Figure 4). The board isdesigned to power sensors ranging within 5-30V input volt-age. It provides a digitally controlled power switch and hasthree 24-bit ADC channels for current measurements. The

board is housed in an IP56 box and uses an external antennaplugged to the U.FL connector of the MagoNode. The thirdboard, namely MNA-MultiSensors-Board, is designed to in-terface a great variety of sensors, ranging from vibrating-wire strain gauges, to weigh scale systems and resistive sen-sors. The purpose of this board is meant to demonstrateflexibility of the platform with respect to the wide selectionof sensors for structural health monitoring applications.

Figure 3: The MNA-Board

Figure 4: The Current-Loop Board

5. REFERENCES[1] WSense website. http://www.wsense.it/

[2] Iris, TelosB, Micaz motes. http://www.memsic.com/

[3] ETSI EN 300 328 V1.8.1 (2012-04).http://www.etsi.org/

[4] FCC CFR 47. https://www.fcc.gov/

[5] ZigBee Specifications. http://www.zigbee.org

[6] ZigBit ATZB-A24-UFL/U0. http://www.atmel.com

[7] Dresden Elektronik deRFmega.http://www.dresden-elektronik.de

[8] TinyOS. http://www.tinyos.net/, Contiki.http://www.contiki-os.org/

[9] Texas Instruments Application Note AN086.http://www.ti.com

[10] Jennic support website.http://www.jennic.com/support/solutions/00002