With the price of oil soaring and a worldwide debate raging over how to address the issue, it can be easy to forget that the conservation of another precious resource — water — should be top-of-mind as well. Water leaks from appliances in homes and businesses are a serious problem, wasting water at an alarming rate and often causing severe damage.

When AquaOne Technologies, Westminster, Calif., decided to tackle this environmental problem with a high-tech approach, their research uncovered some staggering numbers. According to an American Water Works Association study, leaks from toilets in Los Angeles account for 700 million gallons of water lost per day, which is enough to supply 2,200 average sized homes with water for a year. In addition, 17 percent of insurance claims are related to indoor water appliance problems, amounting to more than $4 billion in losses per year. Unfortunately, these leaks can be the size of pinholes and are nearly impossible to detect.

Assembled version of the H2ORB unit.

Because of the sheer volume of loss attributed just to toilets, AquaOne set out to develop a tank sensor that could reduce the problem to a statistical zero. Not with some overly expensive “smart toilet,” or a technology that would require a team of technicians to install, but with a cost-effective device that could be installed in a matter of minutes by an average home or business owner.

The first attempt at developing such a product was successful, but ultimately not the ideal solution. The design was too large, using wired bowl and tank sensors that required battery replacement after 12 months. AquaOne went back to the drawing board to create a smaller, lower-power solution that could be implemented wirelessly.

To achieve these new goals, they turned to Texas Instruments to provide both a microcontroller that could handle their systems’ size and power requirements, as well as TI’s proprietary Radio Frequency Identification (TI-RFid) technology for remote sensing. After selecting the ultra low-power MSP430 MCU and linking it with the RFID, AquaOne was able to develop their breakthrough product: the H2ORB.

The H2ORB is compatible with all conventional tank toilets and can be easily installed at the wall where the incoming water is located near the base of the toilet bowl. The system comes with two wireless sensors — attached to the toilet bowl, and on the perimeter of the toilet tank — that monitor water flow. The bowl sensor detects toilet bowl overflows. The dual-tank sensor unit is attached to the rear of the toilet tank, with the sensor adjusted to the waterline mark.

When a problem occurs, either the bowl sensor or the dual-tank sensor automatically send a signal to H2ORB to stop water flow, sound an alarm and activate a light alert, indicating a potential bowl overflow. If the H2ORB discovers a leaking toilet, it will cut off the water supply to that toilet only. No other outlet is affected.

The “brains” of the H2ORB control units and sensors are TI’s 16-bit, ultra-low power MSP430F413 MCU. The MSP430 MCU platform leverages both high-performance analog and mixed signal processing technologies and enables system designers to simultaneously interface to analog signals, sensors and digital components while maintaining low-power consumption. With integrated 8 KB of flash memory and 96-segment LCD driver, the MSP430F413 MCU has a real-time clock standby power requirement of only 0.7 micro-amps. By leveraging this ultra, low-power consumption, AquaOne was able to achieve five-year operation from the control units’ standard coin-cell batteries, which are easy to replace by the owner/user.

Additionally, the MSP430 MCU can wake up from sleep mode to highest processing speed in an industry best 6 microseconds. This “instant on” wake-up time was particularly important for AquaOne’s system, which needs to stay in standby as long as possible without using the central-processing unit. When the system wakes up, it must do so as quickly as possible, sense any leakage or overflow, and if there is none, return to standby right away. With its low standby power and quick power up, the MSP430 MCU was ideal for this particular application.

Each remote sensor includes an MS430F413 MCU as well as a proprietary TI RFid device to monitor inputs from the external tank and bowl sensors. TI is the world’s largest integrated manufacturer of RFID tags, RFID smart labels, and RFID reader systems. Approaching 500 million RFID tags manufactured, TI RFid technology is used in a broad range of RFID applications worldwide including automotive, contactless payments, laundry, library, livestock, pharmaceutical and healthcare, retail supply chain management, and ticketing.

AquaOne utilizes RFID technology in the tank sensor to allow continuous communication between the control unit and wireless remote sensors. It detects faults such as a slow leak or a stuck open flapper, while the bowl sensor detects when the water level reaches imminent overflow. Each sensor wirelessly signals the main unit when a fault is detected. The main unit will then react according to the fault and a user-defined preference. An actuator powered by the H2ORB button battery closes a valve to shut off water flow. Because the control unit is looking for specific RFID signals, it will not respond to a signal from a sensor on a nearby toilet.

Fig. 1. Block diagram of the TI MSP430F413 MCU.

Additionally, AquaOne has programmed seven different profiles into their system to meet end users’ selective needs. One program, for example, is a “Hospitality” setting for systems in hotels. This profile does not allow the system to send out potentially disturbing audio alarm in response to leaks and problems. Instead, the system flashes an LCD to notify facilities of a problem and relays information regarding the room, what happened, what time the incident occurred, etc. This way, maintenance can determine whether the problem is an emergency, or whether they can wait until a hotel patron checks out before fixing the problem.

Myriad opportunities exist for implementing H2ORB technology. AquaOne addressed toilets first because of the more than 1.2 billion toilets in homes and businesses in the U.S.. Designs are also in the works for washing machines, hot water heaters, showerheads and sprinkler systems. After toilets, clothes washers are the most likely source for costly and damaging leaks in the home.

A solution to this problem will be available from AquaOne before year’s end. The washer monitor design uses flow management detection in conjunction with the appliance’s solenoid valve. The monitor will look at the expected water flow, and shut off the water supply if flow is too high or if there is flow and the washer is in the “off” mode.

A design advantage with washers is that the control unit will be larger, and thus easier to produce, than the 3-in. H2ORB. Initially, AquaOne will design solutions for retrofitting existing washing machines, but the company is also working with OEMs to incorporate their technology directly into new appliances.

For more information email: controlanswers@list.ti.com