General Electric’s healthcare laboratory in Bangalore contains some of the company’s most sophisticated products—from giant body scanners that can accommodate the bulkiest American football players to state-of-the-art intensive-care units that can nurse the tiniest premature babies. But the device that has captured the heart of the center’s boss, Ashish Shah, is much less fancy: a handheld electrocardiogram called the Mac 400.

The device is a masterpiece of simplification. The multiple buttons on conventional ECGs have been reduced to just four. The bulky printer has been replaced by one of those tiny gadgets used in portable ticket machines. The whole thing is small enough to fit into a small backpack and can run on batteries as well as on the mains. This miracle of compression sells for $800, instead of $2,000 for a conventional ECG, and has reduced the cost of an electrocardiogram to just $1 per patient.

In Chennai, 202 miles farther east, Ananth Krishnan, chief technology officer of Tata Consultancy Services (TCS), is equally excited about an even lower-tech device: a water filter. It uses rice husks (which are among the country’s most common waste products) to purify water. The device is not only robust and portable but also relatively inexpensive, giving a large family an abundant supply of bacteria-free water for an initial investment of about $24 and a recurring expense of about $4 for a new filter every few months. Tata Chemicals, which is making the devices, hopes for an eventual market of 100 million.

GE and TCS are doing something more exciting than fiddling with existing products: they are taking the needs of poor consumers as a starting point and working backward. They are producing radically simpler products in order to reduce costs: instead of adding ever more bells and whistles, they strip the products down to their bare essentials. But there is more to frugality than simply cutting costs to the bone. Frugal products need to be highly adaptable.

Anurag Gupta, a telecom entrepreneur, has reduced a bank branch to its essence—a smartphone and a fingerprint scanner—so that banks can take ATMs to rural customers. These products also need to be tough and easy to use. Nokia’s cheapest mobile handsets come equipped with flashlights (because of frequent power cuts), multiple phone books (because they often have several different users), rubberized key pads, and menus in several different languages. Nor does frugal mean second-rate: emerging-market consumers are obsessed by both value-for-money and the latest trends. GE’s Mac 400 ECG incorporates the latest technology. Many inexpensive mobile handsets allow users to play video games and surf the net.