Ultra-Compact Wireless Sensing System

Wireless sensors can become much more useful as they get smaller. They are less intrusive, can be put on many more subjects, and therefore enable new kinds of sensing applications, especially in wearable ones.

What is challenging is not just making a small system, but to make the small system work well.

  1. battery: very difficult to shrink; limited energy capacity; difficult to recharge wirelessly; aging effect

  2. antenna:  also difficult to have both high efficiency and small size at the same time.

  3. limited memory:  RAM takes up most of the chip area and power, but small RAM makes it difficult to have OS, run applications, and manage communication protocols.

  4. expandability:  to eliminate redundant effort and maximize reuse, the platform should support an expansion interface for connecting to different types of sensor modules. However the expansion connector takes up much room and can be fragile.

  5. packaging: waterproof packaging is often requested but it is difficult to fit


Quick Facts

Size:     13x11x7mm (incl. battery)

Weight:    0.6g (excl. battery)

                 1.8g (incl. battery)

Data rate:    1Mbps max

TxPower:  <10mA@3V, 0dBm

RxPower:  21mA@3V, 1Mbps

Battery:    custom 40mAh rechargeable Li polymer

Sensors:    3-axial accelerometer and temperature sensor (H34C), light sensor

Expansion: flex-PCB

Battery life: 12 hrs @20% Tx duty

MCU: nRF24E1


  1. EcoMote and EcoBase

  2. Development boards:
    debugging board, programmer, battery charger

  3. Expansion modules
    transflash, breakout board

Software [to be updated]

  1. Tool download

  2. Compilation instructions

  3. Programmer setup


  1. pre-term infant monitoring

  2. dance performance

  3. structural health monitoring

FAQ [to be updated]

  1. performance comparison

  2. availability

  3. structural health monitoring

About [please see credits]

  1. People

  2. Sponsor

Eco is an ultra-compact, expandable wireless sensor platform.

(June 2008) “Eco Kit” is being available to researchers in limited quantities. Each kit consists of five nodes, one Ethernet base station, one charger, and one development board. More details will be made available soon.