Heart pulse detector with speed control for treadmill

Abstract

The present invention offers a heart pulse detector. Two pairs of contact electrodes mounted on each handrail of treadmill separately. A electrocardiography heart pulse detector built in the control panel of the treadmill has input terminal which electrically connected to the contact electrodes. A front end circuit within the heart pulse detector receives the electrical cardio signals of a user from the input terminal and preprocesses the electrical cardio signals for later processing by the reminder functional blocks of the heart pulse detector. A hand touching detection circuit assembly in the heart pulse detector is also connected to the input terminal. The hand touching detection circuit sense the signals from the input terminal and send out hand on/off data for using to control the speed of the treadmill and to control the operation of the heart pulse detection.

1 . A heart pulse detector used in a treadmill that including a base frame, a motor driven tread belt, a rightup frame with a left handrail and a right handrail, a control panel, the heart pulse detector comprising:
 a plurality of sensor on the left handrail and the right handrail for obtaining electro cardio signal from the user;   an instrument amplifier for amplifying the electrocardio signal;   a common driver for providing a common reference voltage to said instrument amplifier;   a heart pulse detector for detecting a heart pulse signal in response to the amplified electro cardio signal from the output of said instrument amplifier and for producing a digital pulse that is synchrony with the heart pulse signal and is transmitted to the microprocessor in the control panel for calculating the heart pulse rate of the user;   said plurality of sensor comprising a first pair of contact electrodes and a second pair of contact electrodes;   said first pair of contact electrodes comprising a first contact electrode and a second electrode mounted on the left handrail of the treadmill separately;   said second pair of contact electrodes comprising a third contact electrode and a fourth electrode mounted on the right handrail of the treadmill separately;   said first contact electrode and said third contact electrode being connected to the inputs of said instrument amplifier;   said second contact electrode and said fourth electrode being connected to the output of said common driver;   a hand touch detection circuit for receiving the signals from said first contact electrode and said third contact electrode and for producing a plurality of hand touch signals to indicate whether said first pair of contact electrodes and/or said second pair of contact electrodes are touching with the hand of the user;   said plurality of hand touch signal will be transmitted to the microprocessor in the control panel for performing the speed control of the treadmill;   said common driver will output a high level voltage when said plurality of hand touch signal indicate that said first pair of contact electrodes and/or said second pair of contact electrodes are not touching with the hand of the user.   
   
   
       2 . The heart pulse detector as recited in  claim 1 , wherein said hand touch detection circuit further comprises a data encoder for converting said plurality of hand touch signal into a formatted serial data signal for transmitting to the microprocessor in the control panel for performing the speed control of the treadmill. 
   
   
       3 . The heart pulse detector as recited in  claim 2 , wherein said hand touch detection circuit further comprises:
 a first inverter for responding to the signal at said first contact electrode and providing a first left input signal;   a first comparator for responding to the signal at said first contact electrode and providing a second left input signal;   a second inverter for responding to the signal at said third contact electrode and providing a first right input signal;   a second comparator for responding to the signal at said third contact electrode and providing a second right input signal;   a circuit for providing reference voltage to the positive input of said first comparator and the positive input of said second comparator;   a processor for responding to said first left input signal, said second left input signal, said first right input signal, and said second right input signal, and providing a first hand touch signal to indicate whether only said first pair of contact electrodes are touching with hand of the user and providing a second first hand touch signal to indicate whether only said second pair of contact electrodes are touching with hand of the user and providing a third hand touch signal to indicate whether said first pair of contact electrodes and second pair of contact electrodes are touching with hands of the user at the same time.   
   
   
       4 . The heart pulse detector as recited in  claim 3 , wherein said processor further comprises a timer for generating a predetermined period of timing signal as a reference for processor itself.