Open Air Cinema ("Cinebike")

Open Air Cinema (OAC), an outdoor-cinema equipment company, developed the system after its inflatable-screen equipment was used for the January 2014 Kiev screenings, and published the build as Hackaday.io project 5665, "Cinebike Human Powered Cinema". A generic electric-scooter motor, driven by a friction spindle machined from a skateboard wheel, charges two chained Goal Zero Sherpa 100 packs through a custom regulator; the packs' laptop port powers the Optoma ML750 directly, so there is no inverter in the chain, and the battery buffer means constant pedalling is not needed while audience members take turns. The design continues in generator bikes the Open Air Cinema Foundation donated to Cine Bajo El Cielo in Oaxaca; the operator states (September 2026) that the Cinebike itself was a demonstrated concept build and never an operating cinema line.

Specifications

What do these labels mean?

Field	Value	Confidence	Sources
Generator	24 / 200 V / W electric-scooter motor (generic; no make or model documented)	Documented	^2,4
Mechanical coupling	Skateboard-wheel friction spindle pressed on rear tire	Documented	²
Open-circuit generator voltage	60 or more V (strong rider, before regulation)	Documented	²
Voltage regulator output	14.1 VJust above the Sherpa packs' 14 V minimum charge voltage; wiring is cross-connected because the motor is mounted in reverse.	Documented	²
Battery buffer	2 × Goal Zero Sherpa 100, 98 Wh each 196 Wh combinedThe build log documents the chained pair; the 98 Wh capacity is Goal Zero's own published rating for the original 2014–2015 Sherpa 100 — not the 94.7 Wh of the later Sherpa 100AC.	Manufacturer rating	^1,2
Battery charge input	45 each / 90 combined W (two packs chained)	Documented	²
Projector model	Optoma ML750The Hackaday news article's 'Optomo 750' is a typographical error.	Documented	^3,2
Projector native input	19 V DC, from the Sherpa packs' laptop port; no inverter	Documented	²
Projector draw	over 60 WBuilder-reported ('our projector pulls over 60 watts').	Operator-stated	²
Projector rated consumption	max 62 W (Optoma ML750, US model)Optoma's own datasheet figure for the ML750 the build uses. The EU-market ML750e is rated separately at 45 W minimum / 65 W maximum.	Manufacturer rating	⁵
Rider rotation	1 at a time, 5–10 minute stints	Documented	⁶
Charge ceiling vs. draw	90 W input vs. >60 W drawApproximately 1.5× input margin at good events, per the builder.	Documented	²

History

In January 2014, during the Maidan protests, the founder of Open Air Cinema showed a Ukrainian-dubbed version of Jehane Noujaim's The Square from a bicycle generator opposite Khreshchatyk metro — six screenings before he was barred from Ukraine on 22 January — and the Open Air Cinema Foundation Ukraine, founded that November, later fielded the CineBike at Kyiv cycling events ^7,8. See Kyiv, January 2014: The Square on the Maidan. The prototype was tested at the Bicycle Collective in Portland, Oregon, with local e-bike and framebuilding partners ^4,6.

Line diagram tracing the Cinebike's power path from pedals to a regulator, two chained battery packs and the projector's nineteen-volt input — Rider → scooter motor → 14.1 V regulator → 2 × Sherpa 100 → ML750 at 19 V^4,3,2,1 Image: BicycleCinema.org, drawn from the research corpus

Technology

The generator is a generic electric-scooter motor — the project's component list records no make or model ⁹ — and a single casual rider cannot hold the projector's draw indefinitely, so the paired Sherpa packs absorb the deficit and recharge during strong pedalling or idle intervals; two packs are chained because one pack's 45 W charge-input limit would otherwise throttle replenishment below the projector's draw ². The stand went through four documented iterations: a commercial trainer-stand concept, rejected as "not fun to pack while riding to a village at the top of a mountain"; a stand "built from recycled bike parts" with quick-release legs, abandoned as "bulky, a bit dangerous"; an axle-mounted rear rack that rotates down to become the stand, co-designed with Mike Cobb of Framebuilder Supply; and the Bike Friday Haul-A-Day cargo bike with fold-down legs integrated into the frame ².

Four-step strip illustrating the Cinebike's stand iterations from a trainer concept to a cargo bike with integrated legs — Trainer concept → recycled stand → rotating rack → Haul-A-Day legs^4,3,2,1 Image: BicycleCinema.org, drawn from the research corpus

People and community

The Open Air Cinema Foundation donated Cinebike-derived Haul-A-Day generator bikes to Cine Bajo El Cielo / "Ciclocinema" in Oaxaca, led by Claudia G. Covarrubias, which used them to power community premieres of locally produced children's stop-motion films; Bike Friday recorded in January 2017 that the team had "traveled 7000 miles to bring pedal-powered movies to over 50 communities in Mexico", with activity continuing across Oaxaca, Chiapas and Veracruz ^10,11.

In their own words

"A strong rider can put out 60v or more from the motor." ²

"…an outdoor theater entirely powered by the pedal strokes [of] the audience… A crowd of 30 people can enjoy a film and volunteer to pedal for 5 or 10 minutes each." ⁶

Corrections and confidence notes

The welded A-frame sometimes attributed to the project does not appear in the build log, which documents the four stand iterations instead ². The EU-market ML750e, a different model that appears elsewhere in this directory, is rated 45 W minimum and 65 W maximum ¹². The entry had been recorded as dormant because no new Cinebike product or event was found after 2019; the operator's September 2026 statement that the Cinebike was a demonstrated concept build, never an operating cinema line, is the basis of the historical status.