本研究利用PPG(Photoplethysmogram)所量測的心跳訊號,藉由低成本的系統晶片MSP430擷取訊號並運算出其心跳間隔時間,再利用藍芽通訊將數據傳送至手機端進行相關頻譜轉換與心率變異分析,提供我們觀察自律神經協調性,不只提供自己了解身心狀況,也可以協助醫院醫生診療之用,整體系統具體積小方便攜帶、低成本、與簡易操作介面等特性。 所使用之系統晶片為MSP430G2553其記憶體為512 Byte、含一10 Bit A/D供量測系統截取量測訊號,相關量測訊號設定為取樣週期10ms相當於取樣頻率100 Hz取樣數目每200個為一個循環總共循環150次,系統晶片進行運算心跳與心跳之間間隔再將運算結果利用藍芽通訊將數據傳送至手機端進行相關頻譜轉換與心率變異分析,運算後主要的顯示項目為:TP(total power)、HF(high frequency power)、LF(low frequency power)、LF/HF(低高頻功率比)。
The study uses Photoplethysmogram (PPG) to detect the heart beat signals. We use the lost-cost MSP430 to obtain signals and calculate the R-R interval, and use Bluetooth to send data to a mobile phone for converting signals and analyzing heart rate variability. Thus, it can help us to observe the balance between sympathetic and parasympathetic nervous system; besides, it also can help doctors to diagnose diseases. The system has many features, such as small, portable, low-cost, and easy-operated, etc. The system-on-chip is MSP430G2553 and its memory is 512 Byte, including a 10 Bit A/D measuring system to intercept measuring signal. The sampling cycle is set as 10 ms, which is equal to sampling frequency of 100 Hz. Every 200 sampling number is sampled in loop and total loops are repeated 150 times. System-on-chip calculates the intervals between heart-beats and then uses wireless Bluetooth to transmit the results to a mobile smart phone to carry out heart rate variability analysis. Main display values displaying on the smart phone are: TP (total power), HF (high frequency power), LF (low frequency power), LF/HF (high frequency and low frequency power ratio). The experimental results show the system can obtain the different HRV values when a person is standing and lying down.