An apparatus comprising: first, second and third printed circuit boards (602, 604, 606); first and second integrated devices (612, 620) coupled to the third printed circuit board, the first integrated device comprising means for providing wireless communication; means for generating a sound wave, the means for generating a sound wave coupled to the first printed circuit board; means for detecting a sound wave, the means for detecting a sound wave coupled to the third printed circuit board; means for providing power to the first and second integrated devices, the means for generating the sound wave and the means for detecting the sound wave, the means for providing power comprising a plurality of button cell batteries including first and second button cell batteries spaced from each other, and first, second and third flex boards (608, 618, 628), each being at least partially wrapped around a button cell battery of the plurality of button cell batteries, each flex board including one or more interconnects to provide electrical paths between two or more points or components, wherein the first flex board is coupled to the first and second printed circuit boards (602, 604), wherein the second and third flex boards (618, 628) are each coupled to both the second and third printed circuit boards (604, 606), wherein the first button cell battery is located between the first and second printed circuit boards (602, 604), the first and second flex boards (608, 618) at least partially wrapped around the first button cell battery, wherein the second button cell battery is located between the second and third printed circuit boards (604, 606), the third flex board at least partially wrapped around the second button cell battery, wherein the apparatus has a length of about 2.4 centimeter (cm) or less, and a diameter of about 1.2 centimeter (cm) or less. first, second and third printed circuit boards (602, 604, 606); first and second integrated devices (612, 620) coupled to the third printed circuit board, the first integrated device comprising means for providing wireless communication; means for generating a sound wave, the means for generating a sound wave coupled to the first printed circuit board; means for detecting a sound wave, the means for detecting a sound wave coupled to the third printed circuit board; means for providing power to the first and second integrated devices, the means for generating the sound wave and the means for detecting the sound wave, the means for providing power comprising a plurality of button cell batteries including first and second button cell batteries spaced from each other, and first, second and third flex boards (608, 618, 628), each being at least partially wrapped around a button cell battery of the plurality of button cell batteries, each flex board including one or more interconnects to provide electrical paths between two or more points or components, wherein the first flex board is coupled to the first and second printed circuit boards (602, 604), wherein the second and third flex boards (618, 628) are each coupled to both the second and third printed circuit boards (604, 606), wherein the first button cell battery is located between the first and second printed circuit boards (602, 604), the first and second flex boards (608, 618) at least partially wrapped around the first button cell battery, wherein the second button cell battery is located between the second and third printed circuit boards (604, 606), the third flex board at least partially wrapped around the second button cell battery, wherein the apparatus has a length of about 2.4 centimeter (cm) or less, and a diameter of about 1.2 centimeter (cm) or less.