A wireless input-output device may gather touch input from a user. The touch input may be wirelessly transmitted to external wireless equipment such as a computer. The wireless device has a touch sensor and a solar cell that converts ambient light into electrical power. Wireless communications circuitry transmits the touch input to the external equipment using the electrical power from the solar cell. Energy storage devices such as a capacitor and a battery can be charged using the electrical power. The wireless device may have a transparent cover layer. The touch sensor may be a transparent touch sensor that is located between the cover layer and the solar cell or the solar cell may be a transparent solar cell that is located between the transparent cover layer and the touch sensor.