Photophonics is a technology that I developed in collaboration with sound artist Nick Ryan. It was originally designed for the installation piece DX17 which was completed as a commission for the Duxford Imperial War Museum. The technology allows the transmission of hi-fidelity audio through visible light. The idea initially came about as a solution to transmitting a unique audio experience to a visitor based on their position in space. For this particular installation the system needed to support up to 20 visitors simultaneously, and it was desired to have 100 individual audio locations around a sculptural piece. To develop this idea I designed both an analogue audio emitter and receiver circuit which converted the audio signals to light, and then back to audio. I was very excited about the thought of potentially coming up with something new! but after about a week of working on the project I discovered that Alexander Graham Bell had already invented this technology about 200 years prior.. the Photophone…
I designed a PCB for both the emitter and the receiver circuits, within specified geometric constraints. The emitter circuit was designed to fit inside a specific torch housing (which you can see photos of further down the page) and the receiver was designed to fit inside a custom-designed handheld device. The receiver was battery powered by a 3.7v LiPo battery and made to be USB rechargeable. This low supply voltage prove to be quite difficult with as it does not provide sufficient headroom for specific amplification steps in the circuit. The final result however still achieved a surprisingly high level of audio fidelity, and was capable of driving a wide range of variable impedance headphones.
For the design of the receiver PCB I collaborated closely with designer Phil McNeill of Kin design. This helped to ensure that by the PCB and the battery would fit inside the handheld device while maintaining an optimal position for the light sensing used for receiving the signal. It also allowed us to position the volume control, headphone jack and USB socket components on the PCB to interface nicely with the 3D printed casing.
For this installation I had to fabricate a total of 120 working emitter devices and 40 handheld receiver devices! Thankfully we outsourced most of the PCB assembly however there was still a number of manual tasks to complete with the assembly of the torch + emitter devices. The fitting of these devices to the sculptural structure was also an incredibly difficult task, not to mention the insane amount of cable routing! The final piece was breathtaking though, and visitors really enjoyed the profound of experience of being able to listen to light! You can read more about the artwork here.