Flashing Light Safety

Strobotorch is a flashlight signaling tool. It is meant to point away from people. It is not intended to be stared at directly, especially not close up, in the dark, or while intoxicated or otherwise impaired.

Bright flicker can be uncomfortable or unsafe. In some people it can trigger photosensitive seizures. In controlled research settings, stroboscopic light can also produce transient visual hallucination-like effects such as colors, geometric patterns, motion, tunnels, grids, or other simple visual phenomena. That research is included here as a warning, not as a feature claim.

Do Not Use This App For

• Staring into the flashlight.
• Trying to induce hallucinations, visions, meditation effects, or psychedelic effects.
• Testing whether you or someone else is photosensitive.
• Medical treatment, therapy, relaxation, entrainment, brainwave synchronization, gamma stimulation, fractal phototherapy, or visual training.
• Use around people who have not agreed to possible flashing-light exposure.

Stop Immediately If

Stop the torch and move away from the light if anyone experiences discomfort, eye strain, headache, migraine aura, dizziness, nausea, anxiety, confusion, visual snow-like static, afterimages, trails, disorientation, panic, or any seizure-like symptom.

If someone is unexpectedly exposed, turn away from the light source and stop the session. Do not keep watching the light to understand the effect.

Seizure And Photosensitivity Risk

Photosensitive epilepsy is uncommon, but it is real. The Epilepsy Foundation states that flashing light and certain visual patterns can trigger seizures in some people, and that some people do not know they are sensitive until an event occurs. The same guidance notes that brightness, contrast, distance, wavelength, eyes-open or eyes-closed viewing, and flash frequency all matter.

Public safety standards for web content therefore use a conservative rule: avoid flashing, or keep it below the relevant flash thresholds. WCAG Success Criterion 2.3.1 says web content should not flash more than three times in any one second unless the flash is below defined thresholds. Strobotorch uses a 3 Hz direct-viewing cap for the same precautionary reason, even though a phone flashlight is not a web page and can be much brighter at close range.

For the complete reference list, see the Strobotorch source library. Key safety sources:

• Epilepsy Foundation: Photosensitivity and seizures
• Epilepsy Action: Photosensitive epilepsy
• Epilepsy Society: Photosensitive epilepsy
• W3C WAI: Understanding WCAG 2.3.1, Three Flashes or Below Threshold

Why Direct Staring Is The Wrong Use

Stroboscopic-light research is very clear that flicker can be perceptually active. Reviews describe bright periodic light, often around 5-50 Hz and often viewed through closed eyes or diffusion, as capable of inducing visual hallucinations, mainly colors and geometric patterns. Several studies report strong effects around the alpha range, especially near 10 Hz, with rhythm and frequency affecting what people see.

That does not mean a phone flashlight is a controlled research strobe, and it does not mean Strobotorch can or should reproduce those experiments. It means the safe instruction is simple: do not stare into bright flicker.

Key evidence:

• Bartossek, Kemmerer, and Schmidt (2021) tested 3 Hz and 10 Hz closed-eye flicker and reported vivid simple visual effects, strongest in the 10 Hz condition. Participants were screened, including EEG-based photosensitive epilepsy screening and mental-health/drug-use exclusions. PLOS ONE
• Amaya et al. (2023) tested rhythmic and arrhythmic flicker at 3, 8, 10, and 18 Hz. Rhythm and frequency affected simple visual hallucination ratings, and 10 Hz rhythmic flicker produced the strongest perceptual changes in their tested set. PLOS ONE
• Shenyan et al. (2024) compared Ganzflicker and Ganzfeld and used 10 Hz Ganzflicker because earlier work suggested 8-12 Hz, especially 10 Hz, is a suitable range for eliciting visual pseudo-hallucinations. Scientific Reports
• Hewitt et al. (2025) review the history, phenomenology, and mechanisms of stroboscopically induced visual hallucinations and emphasize safety precautions for epilepsy and bright-light sensitivity. Neuroscience of Consciousness

Historical Context

Hewitt et al. (2025) is the best single review to start with if you want to understand why stroboscopic light is treated here as a serious perceptual stimulus and not as a novelty effect. The review links early subjective-vision work, clinical and laboratory stroboscope research, Brion Gysin and Ian Sommerville’s Dreamachine lineage, modern Dreamachine-style public installations, and current neurophenomenology.

The important safety takeaway is not that Strobotorch should reproduce that history. It is the opposite: bright rhythmic flicker has a long record of producing color, geometry, motion, and altered-vision reports under controlled conditions, so a consumer flashlight app should communicate clearly, avoid direct staring, and keep high-rate controls behind point-away warnings.

Frequencies Are Not Purposes

Different fields use overlapping frequencies for very different reasons. Strobotorch does not turn those research lines into app claims. The full citation trail for these frequency rows is in the source library.

Sources for the 60 Hz line:

• Alamalhoda et al. (2025): Exploring neural entrainment and synchrony in response to repeated 60 Hz flickering white light in healthy volunteers
• ClinicalTrials.gov: NCT06922812, 60 Hz intermittent white-light stimulation for major depressive disorder

Substances, Impairment, HPPD, And Visual Snow

Do not use the app while under the influence of psychedelics, cannabis, dissociatives, stimulants, alcohol, or other impairing substances. Impairment can make it harder to stop, look away, interpret distress, or keep the light pointed away from other people. Psychedelic and HPPD literature also shows that visual disturbances can persist or recur after hallucinogen use in some people, so it is especially inappropriate to intentionally add bright flicker in that context.

People with HPPD-like symptoms, visual snow syndrome, palinopsia, photophobia, light-triggered migraine, seizure history, or strong anxiety around visual disturbance should avoid flashing modes unless guided by a qualified clinician in a proper clinical context. Strobotorch is not that context.

Sources:

• Vis et al. (2021): On Perception and Consciousness in HPPD: A Systematic Review
• Sampatakakis et al. (2022): Visual snow: A systematic review and a case series
• The broader citation set is maintained in the source library.

Community And Research Context

People use flashing light, Ganzflicker, visual-noise practice, closed-eye visual-field attention, tulpamancy/imposition practice, and prophantasia-related vocabulary in many different communities. Those reports are useful for knowing what claims and risks exist in the world. They are not evidence that a technique works, that hallucinations are desirable, that aphantasia can be cured, or that a consumer flashlight app is an appropriate stimulus device.

The safest evidence split is:

• Controlled research supports the narrow claim that flicker can induce transient visual phenomena in some people under specific conditions.
• Community reports support the narrow claim that people experiment with these ideas and attach strong meanings to them.
• Neither source type justifies using Strobotorch to induce hallucinations or medical effects.

Practical Rules

1. Point the flashlight away from faces, eyes, reflective surfaces, vehicles, crowds, and animals.
2. Keep distance and use the lowest brightness that works for signaling.
3. Do not use around anyone with seizure risk, photosensitivity, migraine triggered by light, visual snow/HPPD-like symptoms, or uncertain consent.
4. Do not use while impaired, sleep-deprived, panicked, or in a setting where someone cannot immediately leave.
5. Treat the app’s frequency numbers as requested Android commands, not proof of measured optical LED frequency.

Strobotorch’s Design Response

• The direct-viewing flash-rate path is capped at 3 Hz.
• Point-away modes require explicit acknowledgement and may request up to 60 Hz only as command-rate signaling/diagnostic output.
• Audio-reactive torch output is off by default and requires the point-away gate before the torch switch is enabled.
• Sessions stop when the app leaves the foreground, when playback ends, or when Stop is pressed.
• The project does not make medical, therapeutic, psychedelic, relaxation, meditation, hallucination, gamma, fractal phototherapy, or brainwave claims.