Lately – as days grew longer – I thought it was time to start a new project, Aero One. The keyword stands for a new portable audio system similar to The Bee, but smaller and lightweight. The weight and the dimensions of The Bee did not allow to carry it on a summer day to a park. A side effect, when not using The Bee was, that 15€ mini speakers came into action frequently. Indeed, they are better than raw smartphone sound, but compared to any loudspeaker with at least a small ambition for high fidelity sound… that’s not comparable. More expensive mobile products have not been an alternative for me, because 1) I rather like to build such stuff on my own and 2) I don’t like hyped music pills, where most of the price is due to the brand.
Let’s head over to Aero One and its requirements:
- Easy to transport: A weight beneath 1kg and an overall volume of not more than 5l
- Robustness: Should be shock resitant and waterproof.
- Proper audio quality: There should be no need to hide from commercial systems
- Music on the go: Powered by a rechargeable battery which enables more than 5h of playing time
- Recharge without disassembly: Best option would be a micro USB port for recharging.
- Recharge on the go: Possibility to recharge the battery with a built-in solar cell (optional)
- Connectivity: Chinch or 3.5mm plug for audio input. Bluetooth is a plus (optional).
- Interaction: There should be at least an on/off-switch. Volume control is a plus (optional).
- Cost: Not more than for a compareable commercial system (<100€).
What have I done so far?
Up to now I bought first electronic components and put them together in a prototype setup (~45€). The central part is the 2x8W audio amplifier and a 3.7V Li-Ion battery with a capacity of 5.6Ah. In between I installed a DC-DC step up module to adjust the input range of the battery to the amplifier (3.7V to 8-19V DC). In addition I connected a 9V solar cell via a DC-DC step down module and a charge controller board to the battery. To test the experimental setup I wired two sattelites of my old Teufel Concept E Magnum. You can find the exact setting on the following image:
Overall the proposed setup worked as intended, but I did not test every facette yet. At first glance charging via the solar cell works, but due to the power of only 1W and some loss due to the intermediate boards this is more a gimmick than a real charging feature. Though it should elongate the playing time. The amplifier has a reasonable audio quality and does not distort when playing with full volume (audio source was a smartphone).
I still have to decide, which speaker I want to use. One possibility is the 10cm Visaton fullrange speaker FR 10 WP. There’s also a 13cm version available. According to the driver I have to plan and build the housing. Additionally I have to think about volume control, Bluetooth connectivity and user interface layout.