Jeri Ellsworth

Jeri Ellsworth (born 1974) is an American self-taught computer chip designer, inventor and entrepreneur. She designed the single-chip Commodore 64 inside the C64 Direct-to-TV joystick, which sold 70,000 units in one day on the QVC shopping channel in 2004. In 2011 she joined Valve to build its hardware research group, where she worked on living-room controllers and on a projection-based augmented reality display. After Valve dismissed her in February 2013 she bought that display technology from the company, co-founded Technical Illusions with fellow ex-Valve engineer Rick Johnson, and developed it as CastAR, which raised just over US$1 million on Kickstarter in 2013 and US$15 million from Playground Global in 2015 before shutting down in June 2017. She then founded Tilt Five, a tabletop AR gaming system built on the same retroreflective projection approach, whose 2019 Kickstarter raised US$1,767,301 from 3,345 backers and whose glasses began shipping in December 2021. Ellsworth is Tilt Five's co-founder and chief executive officer.

Reviewed 20 September 2026. Biography, career dates, Valve, castAR and Tilt Five funding, Kickstarter figures, specifications, quotes and all 30 cited sources. About review dates.

Early life and education

Ellsworth was raised in Dallas, Oregon, by her father, Jim Ellsworth, a mechanic who owned the town's Mobil service station. At age seven she persuaded him to let her use a Commodore 64 that had been bought for her brother and taught herself to program it from the manuals; living in a small rural town with no electronics surplus store, she sourced parts from local amateur radio operators. During high school she designed and sold the dirt-track race cars she raced with her father, using his service station as a workshop, and the business did well enough that she dropped out of school.

In 1995 she went into business with a friend assembling and selling Intel 486-based PCs. The partnership broke up, and she opened her own store nearby, which grew into a chain of five Computers Made Easy shops in small Oregon towns. She sold the stores in 2000 as falling PC prices squeezed margins. She then enrolled in the circuit design program at Walla Walla College in Washington but left in under a year, later describing herself as a cultural mismatch for a school where questioning professors was discouraged.

Career

C-One and the C64 Direct-to-TV

Working on her own, Ellsworth designed circuits that reproduced the behavior of the Commodore 64. The result was a reconfigurable computer, the C-1 (C-One), that could imitate the Commodore 64 and, by changing its configuration, more than nine other early-1980s home computers including Atari, Texas Instruments, VIC and Sinclair machines. She showed it at the Hackers' Conference in 2002, where she received an ovation and job offers, including consulting work for the Mountain View startup Rapport Inc.

Mammoth Toys of New York then hired her to design a Commodore-emulating chip for a joystick. She started the project in late June 2004 and finished in early September, including a last-minute trip to the factory in China. The device squeezed the entire circuitry of the Commodore 64 onto one chip inside a joystick that plugged into a television, ran 30 early-1980s games without cartridges, included five hidden games, and could be modified by hobbyists to add a keyboard, monitor and disk drive. Sold by Mammoth for US$30, it sold 70,000 units in a single day when it was introduced on QVC in November 2004. Ellsworth told the New York Times she was paid at a consulting rate rather than sharing in the windfall, and that the project was "a tribute back to the computer that started it all for me." A European version, the C64 Direct-to-TV (C64 DTV), was announced in January 2005 by Ironstone Partners and The Toy:Lobster Company for a May 2005 launch in Europe, Africa, Asia and Australasia. By 2013 the joystick had sold over half a million units. Apple co-founder Steve Wozniak, whom she had questioned about his Apple II disk controller at a vintage computer festival, told the Times he was "very impressed with her knowledge of all this stuff, and her interest too."

Valve

Ellsworth joined Valve in August 2011 to work on research and development of gaming hardware. Tilt Five's press material states that Valve hired her to build and run its R&D team and that she contributed to technology later used in the HTC Vive. In a September 2012 Engadget interview she described leading a team whose one-year goal was hardware that made Steam games more fun to play in the living room alongside the newly launched Big Picture Mode, with a hardware beta planned for the following year and wearable computing treated as a two-to-five-year prospect. Her team's controller prototypes were aimed at Valve's then-rumored Steam Box. According to Ellsworth, the group's stated mission was to invent "novel user interactions that broaden the Steam user base" and "bring the entire family together in the living room."

On February 13, 2013, Valve fired her; she announced it on Twitter with "Yup. Got fired today. Time for new exciting projects." In a July 2013 podcast she said Valve's flat structure hid "a hidden layer of powerful management structure," compared the atmosphere to high school, said her hardware team had struggled to recruit and to get resources, and said she had been fired for being abrasive; she learned that Rick Johnson, who worked on the same project, had been dismissed the same day.

The augmented reality work came out of the same lab. Tilt Five's account is that a beam splitter in the Valve lab was accidentally rotated, throwing light onto retroreflective material across the room and producing high-contrast images, which set the direction for the projection approach. Ellsworth told UploadVR in 2022 that on the day of the layoff, as she left the meeting, she told Gabe Newell "you should just sell me the technology," and he agreed at once. The price was US$100 plus legal fees; she received the lab's retroreflective-glasses prototypes, optical components, software and computers, and, in her words, "the biggest win was the legal documentation that gave us freedom to operate."

Technical Illusions and castAR

Ellsworth showed the prototype, then called Cast AR, at Maker Faire Bay Area on May 18, 2013. The glasses carried miniature LCD projectors on active-shutter eyewear, projected images onto a retroreflective surface at 120 Hz, and used a camera on the bridge to track infrared LEDs embedded in the surface for head tracking; because the glasses were see-through, wearers kept sight of their surroundings. She had founded Technical Illusions to bring it to market, with a Kickstarter planned for later in 2013 and a target price under US$200 for glasses, wand and surface.

The castAR Kickstarter launched on October 14, 2013 with a US$400,000 goal to move the design from an FPGA prototype to a lower-power ASIC. The kit combined right- and left-eye projectors, active shutter lenses and a head tracker with a retroreflective sheet and a "magic wand" controller; clip-on attachments turned the glasses into a conventional AR display or a fully enclosed virtual reality display, and an RFID grid under the sheet could identify tabletop game pieces. The campaign, listed from Seattle, closed with US$1,052,110 pledged by 3,863 backers; the company said the final retail glasses were expected to weigh under 100 grams.

On August 19, 2015, the company, by then named castAR and based in Mountain View, California, announced a Series A round of more than US$15 million led by Andy Rubin's Playground Global. The release named David Henkel-Wallace as chief executive and described Ellsworth and Johnson as co-founders. In December 2015 castAR offered full refunds to Kickstarter backers at hardware tiers, plus a free consumer unit at the planned 2017 release, rather than ship developer kits that did not match the final design. In August 2016 the Palo Alto company hired former LucasArts president Darrell Rodriguez as CEO and former Disney executive Steve Parkis as president and chief operating officer.

castAR shut down on June 26, 2017 after Playground Global declined to provide further funding and a search for other investors failed. Fewer than 70 employees in Palo Alto and Salt Lake City were laid off, including the Eat Sleep Play game studio staffed by former Disney Infinity developers, and a core group stayed on to sell the technology.

Tilt Five

Ellsworth founded Tilt Five in 2017. The company's press kit gives the founding date as November 2017 and its location as Silicon Valley. Her team put together enough money to buy back the castAR assets from the defunct company, this time with granted patents covering the retroreflective optical technique. Unlike at castAR, she took the chief executive role, which Engadget noted gave her greater control over the product's direction. She told UploadVR in 2022 that she held about a dozen patents covering the current designs.

The Tilt Five Kickstarter launched on September 24, 2019 with a US$450,000 goal, which it reached within 17 hours, and closed on October 29, 2019 with US$1,767,301 from 3,345 backers. The base US$299 pledge included one pair of glasses, a wand controller, the retroreflective game board and accessories; a three-player pack cost US$879. The campaign, listed from Santa Clara, California, estimated delivery of the first kits in July 2020. The glasses weighed about 85 grams, used micro projectors and polarized lenses to deliver a 720p image at up to 60 Hz with a 110-degree diagonal field of view, and carried two cameras for head tracking and for recognizing hands and objects; the game board carried passive retroreflective dots in its border, lit by infrared LEDs on the glasses, for the tracking camera to read. About six hours before the campaign ended, Ellsworth posted an endorsement from Gabe Newell, who said he was "super impressed" with the product.

On October 28, 2020, Tilt Five announced a US$7.5 million Series A round led by SIP Global Partners with BITKRAFT Ventures, Galaxy Interactive and former Valve developer Ken Birdwell, bringing total funding to nearly US$10 million including pre-orders. The first kits shipped to Kickstarter backers on December 22, 2021, roughly a year and a half behind the original estimate, with the company aiming to finish backer deliveries by spring 2022. In April 2022 Ellsworth said the company expected to complete its Kickstarter deliveries that summer, that a starter set then cost about US$359, that Android drivers were nearly done with iOS to follow, and that multiple pairs of glasses would run from a single PC using reprojection. The company reported in January 2023 that nearly all Kickstarter units had shipped and ended its campaign updates.

In a September 2022 hands-on at Gamescom, UploadVR's Harry Baker called Tilt Five "a compelling version of AR that remains unmatched on a consumer level," while noting that it was confined to tabletop use, needed a PC tether per headset, and had a limited content library. At CES 2023 Ellsworth demonstrated several glasses running from one PC, confirmed Catan for the platform, and said her goal was to make Tilt Five "the Nintendo of AR"; a two-person set then cost about US$660. As of September 2026 the Tilt Five website lists the system as out of stock, directs partners and institutions to contact the company directly, and shows a Game Night Bundle at US$699; the site's most recent news post is dated May 2025.

Recognition

Ellsworth is listed in the AWE XR Hall of Fame, maintained by the Augmented World Expo, as an "AR Glasses Pioneer, Tilt Five Founder and CEO"; the entry states that the Tilt Five system has sold tens of thousands of units. In 2004, Lee Felsenstein, designer of the first portable PC and an original Homebrew Computer Club member, described her to the New York Times as "a pure example of following your interests and someone who won't accept that you can't do it."