Hackaday Prize 2023: Supercapacitors allow solar speaker to run in the dark
Solar panels are a great way to generate clean electricity, but require an energy storage mechanism if you want to use their power at night as well. This can be a bit tricky for large solar farms that feed into the grid, which require huge battery banks or pumped storage systems to capture a reasonable amount of energy. It's much easier for small portable solar gadgets, which work great with a small rechargeable battery or even a large capacitor. [Jamie Matthews], for example, built a speaker that runs on solar power but can also work in the dark thanks to two supercapacitors.
The speaker's 3D-printed enclosure is fitted with a front-mounted 60 x 90 mm2 solar panel, which charges a pair of 400 Farad supercaps. Audio input is either via a standard 3.5mm socket or via the analog audio function of a USB-C socket. This same USB port can also be used to directly charge the supercaps when there is no sunlight, or to connect a Bluetooth audio receiver, which in this case will be powered by the speaker.
The solar panel sits right next to the passive radiator before both are covered with speaker fabric.The outer speaker shell, front bezel, and even the passive radiator are printed 3D and spray painted. The radiator consists of a central cap weighed down by two M4 screws and suspended in a flexible membrane. [Jamie] used glue on all the openings to make sure the box stays nearly airtight, which is necessary for the passive radiator to work properly. Speaker fabric is used to cover the faceplate, including the solar panel. It is apparently transparent enough to allow a few watts of solar energy to pass through.
A salvaged three-inch Bose driver is the actual audio source. It is driven by a TI TPA2013D1 chip, which is a 2.7W class-D amplifier with an integrated boost converter. This allows the chip to maintain a constant output power level over a wide supply voltage range, which is ideal for supercapacitor operation, since supercapacitors do not maintain a constant voltage like lithium batteries do. .
[Jamie] has been using the speaker for over nine months so far and has only had to manually charge it twice. It probably helps that it lives in sunny South Africa, but we've seen similar solar audio projects work really well in places like Denmark. If you're taking your boombox to the beach, a sunscreen reminder feature might also come in handy.
Solar panels are a great way to generate clean electricity, but require an energy storage mechanism if you want to use their power at night as well. This can be a bit tricky for large solar farms that feed into the grid, which require huge battery banks or pumped storage systems to capture a reasonable amount of energy. It's much easier for small portable solar gadgets, which work great with a small rechargeable battery or even a large capacitor. [Jamie Matthews], for example, built a speaker that runs on solar power but can also work in the dark thanks to two supercapacitors.
The speaker's 3D-printed enclosure is fitted with a front-mounted 60 x 90 mm2 solar panel, which charges a pair of 400 Farad supercaps. Audio input is either via a standard 3.5mm socket or via the analog audio function of a USB-C socket. This same USB port can also be used to directly charge the supercaps when there is no sunlight, or to connect a Bluetooth audio receiver, which in this case will be powered by the speaker.
The solar panel sits right next to the passive radiator before both are covered with speaker fabric.The outer speaker shell, front bezel, and even the passive radiator are printed 3D and spray painted. The radiator consists of a central cap weighed down by two M4 screws and suspended in a flexible membrane. [Jamie] used glue on all the openings to make sure the box stays nearly airtight, which is necessary for the passive radiator to work properly. Speaker fabric is used to cover the faceplate, including the solar panel. It is apparently transparent enough to allow a few watts of solar energy to pass through.
A salvaged three-inch Bose driver is the actual audio source. It is driven by a TI TPA2013D1 chip, which is a 2.7W class-D amplifier with an integrated boost converter. This allows the chip to maintain a constant output power level over a wide supply voltage range, which is ideal for supercapacitor operation, since supercapacitors do not maintain a constant voltage like lithium batteries do. .
[Jamie] has been using the speaker for over nine months so far and has only had to manually charge it twice. It probably helps that it lives in sunny South Africa, but we've seen similar solar audio projects work really well in places like Denmark. If you're taking your boombox to the beach, a sunscreen reminder feature might also come in handy.
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