What is it?

Sun Flies is a very sensitive and versatile analog amplifier with stereo input and stereo output.

It offers you plenty of opportunities to experiment. You can use various sources of a low power signal at input, such as:

• Photodiodes. Two are included in the kit. These miniature sensors react to various artificial and natural light sources, such as lightbulbs, screens, sun rays scattered by leaves, sand particles falling in front of the sensor, light reflected from water, mirrors, prisms... And they look very cool too!

• Solar cells. Two are included in the kit. Because of their larger surface area, even the tiniest particles, invisible to the naked eye, trigger Sun Flies' enchanting response.

• Coils and inductors. You can listen to electromagnetic fields emitted from various electronic devices. While there are many ready-made devices that do this, here you can experiment with your own designs and make various coils and antennae to carry around, that are easy to swap thanks to the 4-pin header used at input.

• Sensor Ensemble. You can attach various other sensors to the amplifier, any that output small voltage signals. We can't wait to see what else you will think up!

You can listen to a few sound demos here: https://phonicbloom.com/sunflies/#demo

Why did you make it?

I was experimenting with solar panels and accidentally discovered that they are very sensitive detectors of tiny fluctuations in the light. Then I decided to explore this effect further and the sonic results were very interesting. For example, the dust particles sound quite like buzzing flies, and because the circuit is stereo, you can even hear the direction in which they move over the two solar panels.

What makes it special?

Probably the cool PCB with full colour graphics on the solder side. The circuit is quite common implementation of an universal audio amplifier with configurable "wide stereo" effect, and can be used for various other purposes. It is also a nice DIY build which you can complete in an evening.

What is included in the kit?

The DIY kit includes everything you need to build your own Sun Flies (including two photocells and two solar panels). It might not be the best kit for a complete beginner, but with some basic soldering experience you will be able to bring Sun Flies to life.

A printed build guide is included. Please check the linked documentation to see what is involved in building the kit.

How to listen to it?

The headphone connector is a standard 3.5mm jack. Please be careful as the signal coming out from the device might be sometimes quite loud mainly when the sensor connection is mechanically disturbed and is not making a good contact. Because this is primarily intended for recording, there is no quick way to adjust the volume. There are two potentiometers to control amplifier gain, but they are the multi-turn type, so it takes a while for them to go through the whole range - their purpose is to fine-tune the gain to match various sensors. It's a good idea to take your headphones off while powering the circuit on or off. Also, please make sure that it is powered off while you are changing the sensors.

How to power it?

While the circuit is typically powered from a 9V battery via the barrel jack connector, you can use a lower voltage source as well. It works fine from a 3V, 4.5V or 6V source (for example 2-4 AA cells with a suitable battery holder). The powering voltage makes a small difference - when powered from lower voltage, the output volume is slightly lower. The power consumption at 9V is 14.5mA, and at 3V it is 4.5mA.

Is it possible to record the output?

You can record the sounds from Sun Flies just as if you recorded from any other device with a line-out or headphones output, by connecting it to a mixer or a sound card. You can use a headphone splitter cable to hear what you are recording, or use multiple pairs of headphones to share the experience, it will not overload the output.