用二個16:1 取樣 http://www.nxp.com/documents/data_sheet/74HC_HCT4067.pdf 接二個電壓表. 記數器,產生控製信號 http://www.onsemi.com/pub_link/Collateral/MC74HC4060A-D.PDF 也可以用用二個16:1 取樣反接 2x16個LED來代替1個2X7段通道LED.