An Inexpensive Schlieren System
Schlieren imaging, a technique for visualizing heat, sound, or pressure differences in air, is typically expensive due to the need for large optical mirrors. A new, low-cost alternative uses a plastic Fresnel lens, making the system accessible for students and educational settings. This simple design, based on Toepler’s single-field-lens arrangement, achieves effective results with inexpensive, readily available components.
- ▪Schlieren imaging detects disturbances in air by capturing variations in the speed of light caused by heat, sound, or pressure.
- ▪The system described uses a $20 Fresnel lens with a 250mm diameter and 1,000mm focal length, making it affordable and accessible.
- ▪Components include a white LED light source, a knife edge (or black paper), a camera, and a Fresnel lens arranged in Toepler’s single-field-lens configuration.
- ▪The setup allows students to experiment with the position of heat sources to understand system sensitivity and image quality.
- ▪A 300mm camera lens focused on the heat source captures visible distortions caused by heated air bending light rays.
- ▪The LED is powered by a 5VDC supply with a 330-ohm resistor to prevent overheating.
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| Original publisher | PetaPixel |
| Canonical URL | https://petapixel.com/2020/01/18/a-simple-and-inexpensive-schlieren-optical-system-using-a-fresnel-lens/ |
| Publication time | Sun, 17 May 2026 01:31:58 +0000 |
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A Simple and Inexpensive Schlieren Optical System Using a Fresnel Lens Jan 18, 2020 Ted Kinsman Schlieren imaging is a fairly standard optical technique for visualizing heat, sound, or pressure differences in air. Technically, a schlieren system is able to see clear disturbances in air due to slight differences in the speed of light in the air. The technique can be sensitive enough to see the heat rising off a human hand at room temperature. freestar.config.enabled_slots.push({ placementName: "PetaPixel_728x90_ATF_Desktop", slotId: "PetaPixel_728x90_ATF_Desktop" }); freestar.config.enabled_slots.push({ placementName: "PetaPixel_300x600_300x250_320x50_Mobile", slotId: "PetaPixel_300x600_300x250_320x50_Mobile" }); High-quality schlieren systems typically use large optical mirrors that are…
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