A Bluetooth transceiver design that dramatically boosts battery life could enable richer sensor networks and extend the lifetime of implanted medical devices. At the International Solid-State Circuits Conference in San Francisco this week, engineers from European research organization imec and Renesas Electronics Corporation (a semiconductor company in Tokyo) showed off the record-low-voltage communications chip.

Over the past eight years, engineers have brought down Bluetooth power consumption by a factor of ten, says Christian Bachmann, program manager for ultralow power wireless systems at imec Holst Centre in Eindhoven, Netherlands. The imec transceiver, which meets the Bluetooth 5 standard, uses 0.8 volts, down from a full volt. That reduction is enough to extend battery life by 50 percent. “This achieves another power of five reduction and will enable new applications,” Bachmann says.

One way the imec-Renesas group managed to trim power requirements was by switching out analog circuits for digital ones. Bachmann says the last few years have seen a lot of innovation in digital radio designs, and the imec group took full advantage. Digital logic is not only more reliable and compact than analog counterparts, it’s miserly in its use of power. One significant switch to digital in the Bluetooth transceiver was in a control circuit called a phase-locked loop. The digital version offers better control, says Bachmann. The team also made architectural changes, including ditching an entire block of analog-to-digital converters in the receiver. Typical systems require two sets in order to ensure quality of the signal; the imec-Renesas converter works with high enough fidelity that only one is needed.

Bachmann is excited about the potential for ultralow-power communications not only to extend battery life in conventional applications, but also to open up new ones. “For wireless sensor networks, communications are the power bottleneck,” says Bachmann. Power-hungry transceivers can rule out the use of low-voltage printed batteries and energy harvesters. More efficient transceivers could open up new possibilities for wearable electronics and distributed sensor networks.

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The Spectacular Collapse of CryptoKitties, the First Big Blockchain Game

A cautionary tale of NFTs, Ethereum, and cryptocurrency security

8 min read
Vertical
Mountains and cresting waves made of cartoon cats and large green coins.
Frank Stockton
Pink

On 4 September 2018, someone known only as Rabono bought an angry cartoon cat named Dragon for 600 ether—an amount of Ethereum cryptocurrency worth about US $170,000 at the time, or $745,000 at the cryptocurrency’s value in July 2022.

It was by far the highest transaction yet for a nonfungible token (NFT), the then-new concept of a unique digital asset. And it was a headline-grabbing opportunity for CryptoKitties, the world’s first blockchain gaming hit. But the sky-high transaction obscured a more difficult truth: CryptoKitties was dying, and it had been for some time.

The launch of CryptoKitties drove up the value of Ether and the number of transactions on its blockchain. Even as the game's transaction volume plummeted, the number of Ethereum transactions continued to rise, possibly because of the arrival of multiple copycat NFT games.

That perhaps unrealistic wish becomes impossible once the downward spiral begins. Players, feeling no other attachment to the game than growing an investment, quickly flee and don’t return.

Whereas some blockchain games have seemingly ignored the perils of CryptoKitties’ quick growth and long decline, others have learned from the strain it placed on the Ethereum network. Most blockchain games now use a sidechain, a blockchain that exists independently but connects to another, more prominent “parent” blockchain. The chains are connected by a bridge that facilitates the transfer of tokens between each chain. This prevents a rise in fees on the primary blockchain, as all game activity occurs on the sidechain.

Yet even this new strategy comes with problems, because sidechains are proving to be less secure than the parent blockchain. An attack on Ronin, the sidechain used by Axie Infinity, let the hackers get away with the equivalent of $600 million. Polygon, another sidechain often used by blockchain games, had to patch an exploit that put $850 million at risk and pay a bug bounty of $2 million to the hacker who spotted the issue. Players who own NFTs on a sidechain are now warily eyeing its security.

Remember Dragon

The cryptocurrency wallet that owns the near million dollar kitten Dragon now holds barely 30 dollars’ worth of ether and hasn’t traded in NFTs for years. Wallets are anonymous, so it’s possible the person behind the wallet moved on to another. Still, it’s hard not to see the wallet’s inactivity as a sign that, for Rabono, the fun didn’t last.

Whether blockchain games and NFTs shoot to the moon or fall to zero, Bladon remains proud of what CryptoKitties accomplished and hopeful it nudged the blockchain industry in a more approachable direction.

“Before CryptoKitties, if you were to say ‘blockchain,’ everyone would have assumed you’re talking about cryptocurrency,” says Bladon. “What I’m proudest of is that it was something genuinely novel. There was real technical innovation, and seemingly, a real culture impact.”

This article was corrected on 11 August 2022 to give the correct date of Bryce Bladon's departure from Dapper Labs.

This article appears in the September 2022 print issue as “The Spectacular Collapse of CryptoKitties.”

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