Air-powered pneumatic systems have a wide range of applications, from train brakes to medical ventilators. However, adding electronic sensors to detect failures can be costly and complex, raising safety concerns. But now, researchers at UC Riverside have developed a new, inexpensive, air-powered logic device to address this issue.
This device can detect and respond to problems in pneumatic systems without the need for electronic sensors. For instance, it has been successfully implemented in medical devices to help prevent blood clots and strokes, offering a more reliable and cost-effective solution without relying on electronic sensors.
Featured in a paper in the Device journal, this innovative computer not only operates using air but also utilizes air to issue warnings. Upon detecting an issue with the life-saving compression machine it monitors, it immediately signals with a whistle.
Intermittent pneumatic compression (IPC) devices are leg sleeves that periodically fill with air to compress a person’s legs, promoting blood flow and preventing clots that can lead to blocked blood vessels, strokes, or even death. Typically, these machines are powered and monitored by electronic systems.
“IPC devices can save lives, but all the electronics in them make them expensive. So, we wanted to develop a pneumatic device that gets rid of some of the electronics, to make these devices cheaper and safer,” said William Grover, associate professor of bioengineering at UC Riverside and corresponding paper author.
Pneumatic systems are an efficient way to transport compressed air, used in emergency brakes for freight trains, bicycle pumps, tire pressure gauges, respirators, and IPC devices. Grover and his colleagues found it logical to use pneumatic logic devices to enhance safety.
This type of device functions similarly to electronic circuits, utilizing parity bit calculations to provide additional information. “Let’s say I want to send a message in ones and zeroes, like 1-0-1, three bits,” Grover said. “Decades ago, people realized they could send these three bits with one additional piece of information to make sure the recipient got the right message.”
The parity bit, a 1 or 0 depending on whether the message contains an odd or even number of ones, detects flaws in the message. Many electronic computers employ this method for sending messages.
An air-powered computer utilizes air pressure differentials through 21 miniature valves to accurately process binary information. When functioning properly, the system operates silently, but any errors trigger a distinct whistle, signaling the need for maintenance. In a demonstration by Grover and his students, the deliberate damage to an IPC device with a knife resulted in an immediate whistle.
“This device is about the size of a box of matches. It replaces a handful of sensors as well as a computer,” Grover said. “So, we can reduce costs while still detecting problems in a device. And it could also be used in high humidity or high temperature environments that aren’t ideal for electronics.”
While IPC device monitoring is just one application, Grover’s next goal is to create a device that can potentially eliminate the hazardous task of manually handling grain in tall silos, a job responsible for multiple fatalities each year. These towering structures, commonly found in the Midwest, often necessitate human entry for redistribution of grain.
“A remarkable number of deaths occur because the grain shifts and the person gets trapped. A robot could do this job instead of a person. However, these silos are explosive, and a single electric spark could blow a silo apart, so an electronic robot may not be the best choice,” Grover said. “I want to make an air-powered robot that could work in this explosive environment, not generate any sparks, and take humans out of danger.”
Air-powered computing has a long history, dating back at least a century. In the past, air-powered pianos capable of playing music from punched rolls of paper showcased the potential of this concept. However, with the advent of modern computing, pneumatic circuits fell out of favor among engineers.
“Once a new technology becomes dominant, we lose awareness of other solutions to problems,” Grover said. “One thing I like about this research is that it can show the world that there are situations today when 100-plus-year-old ideas can still be useful.”
Journal reference:
- Shane Hoang, Mabel Shehada, Zinal Patel, Konstantinos Karydis, Philip Brisk, William H. Grover. Air-powered logic circuits for error detection in pneumatic systems. Device, 2024; DOI: 10.1016/j.device.2024.100507