The Therapeutic Potential of Light
Light is widely believed to have therapeutic benefits for both the skin and the soul, potentially alleviating conditions such as depression and allergies. Various products, ranging in price from tens to hundreds of pounds, are marketed as universal remedies for dust allergies and hay fever. Upon closer examination, these devices operate on a relatively simple principle. They all emit intense red light at a wavelength of 660 nm.
Understanding Phototherapy: Healing Through Light
These devices are rooted in the concept of ‘phototherapy,’ a treatment believed to have positive effects on the human body, triggering healing processes. Biophysicists argue that light at this specific wavelength, 660 nm, can profoundly impact the body. This phototherapy is purported to combat allergic reactions by countering free oxygen radicals and bolstering the immune system, thereby reducing inflammation in mucous membranes. Importantly, since this treatment involves visible light rather than medication, it carries no risk of side effects.
Evaluating the Effectiveness of Phototherapy
Scientific research has indicated that phototherapy may not yield positive results in all cases, with success rates varying but occasionally reaching as high as 72%. In cases where these devices are not available through the NHS or private medical insurance, many individuals consider the do-it-yourself (DIY) route. To house such a DIY phototherapy device, repurposing an old nasal hair trimmer, which can be found for a few pounds or recycled from an existing one, is a practical choice. The selection of this enclosure also dictates the choice of the battery, as it accommodates an AA-size cell holder.
The Circuit Design Challenge and Recycling Opportunity
The circuit design faces a twofold challenge: compactness, due to the limited space within the enclosure, and the capability to power a high-brightness red LED effectively, considering a voltage range between 1 V and roughly 1.6 V. In addressing this challenge, the option of recycling an existing circuit arises. Specifically, the circuit for driving a white LED, as previously featured in a Mini Project by Burkhard Kainka, which was published in Elektor Electronics in June 2002, presents a suitable foundation for adaptation. This existing circuit automatically limits the inductive voltage pulse by the LED itself, ensuring the output voltage aligns with the LED’s forward voltage.
A Versatile and Compact DIY Phototherapy Circuit
The circuit, with its simplicity and minimal components, is well-suited for driving a high-brightness 660 nm red LED in the creation of a DIY phototherapy device. Assembly can be achieved either by soldering the components together directly or using a small stripboard. The circuit operates within a wide voltage range, making it compatible with both an alkaline AA cell and an AA-size NiMH rechargeable cell, both of which provide a voltage of approximately 1.2 V. The circuit’s current consumption is around 20 mA. When constructed accurately, the red LED should illuminate brightly upon powering. With just five to ten minutes of use in each nostril daily, noticeable benefits can be expected after two weeks of treatment.