[ 0033 ] fig1 provides a high level overview of the physical components that comprise the device . the preferred embodiment of the invention includes a metallic mass ( 1100 ) on one face of the device that will serve to attract the device to the reticulum magnet so that it neither can be regurgitated nor passed out through the remaining digestive track . also , the preferred embodiment of the invention includes an inert coating ( 1200 ) surrounding the device . the material may be thin teflon , silicate , or other surface . in the preferred embodiment , the ph probe ( 100 ) extends beyond the boundary of the inert coating whish encompasses the rest of the device . this physical extension is required in order to expose the galvanic material to the hydronium ions within the reticulum of rumen fluid . [ 0035 ] fig2 provides a high level overview of the electronic components and the physical devices that provide the measurements to be transmitted . in the preferred embodiment , the invention is used to measure the ph of the fluid in which the device resides . the sample probe ( 100 ) contains standard galvanic elements that are sensitive to hydronium ion concentrations . the exposed end of the sample probe , see fig1 contains a glass or other material that is integral to the component . such galvanic devices have known linear voltage response curves to ph and temperature . at room temperature , a change of 1 ph unit causes a voltage change of about 60 millivolts , or 0 . 060 volts . at 0 degrees centigrade , 1 ph unit causes a 54 mv change . at 100 degrees centigrade , a 1 ph unit change causes a 70 mv change . at ph of 7 , the voltage generated is 0 mv . the device will need to measure the healthy range of a cow ph , 5 . 8 - 6 . 4 , as well as aberrant values that may range from 4 - 8 . consequently , the device will generate from 0 . 180 v on the low ph range and 0 . 060 v on the high ph range , the voltages being inverted at a ph of 7 . 0 . in the preferred embodiment , the invention will include a reference sample ( 200 ) of a solution of known ph , whose voltage output may be used as a comparison against the sample voltage . the reference sample solution contains a galvanic device made from the same material as the sample probe . both sample and reference voltage outputs can be conditioned . conditioning includes signal amplification using an op - amp , or similar device . in fig2 the op - amps are positioned between voltage source and the multiplexer ( 400 ). additional or alternate conditioning may be achieved with an op - amp or similar device located between the multiplexer ( 400 ) and the a / d converter ( 500 ). in the preferred embodiment , the device includes a component ( 300 ) for measuring the temperature of the fluid in which it is located . this component may be a thermistor , thermocouple , or other device . in the preferred embodiment , the device will be used to measure and report temperature readings many times a day . given this frequency , the thermocouple or other temperature device will be at thermal equilibrium with the surrounding solution to within acceptable tolerance , without making direct physical contact with the fluid mass . in the case of the thermistor device , an input voltage will pass through the component , resulting in an output voltage that is dependent upon temperature . the output voltage from the temperature device will also pass through an op - amp in order to amplify the signal . in the preferred embodiment , the voltage output from the op - amps or other signal conditioning circuitry will go into a multiplexer ( 400 ). we describe the operation of the multiplexer in the text below . the multiplexer selects which input undergoes a / d conversion based on ourput from the sequencer ( 700 ) described below . in the preferred embodiment , the transponder tag ( 800 ) is powered by rectifying the incoming rf carrier signal that is transmitted from the reader . when the tag develops sufficient dc voltage , it transmits the content of its memory array by modulating the rf carrier signal . in the preferred embodiment , the invention will use this dc power supply to provide the voltage needed for all components of the device . alternate embodiments , where the power generated by the tag is augmented by a secondary power source , could use a piezoelectric device or the galvanic voltage generated by the hydronium ion concentration . the circuitry of the device is designed to enable the tag to accept output from any number of sensors regardless of the number of external inputs available on the tag . the invention uses a serializer ( 600 ) to string together the multiple digital outputs of the multiplexer into a single digital string . the single string is output to the tags external input pin ( s ). the serializer may be constructed from a programmable logic device , a field programmable gate array , or other electronic devices . if a tag containing multiple external input channels is used , the serializer may not be required . the modulated rf carrier signal includes the tag id as well as the output from the serializer . in the preferred embodiment , the second input to the sequencer is a clock signal . the clock signal can come from the tag or , if one is not present as a pin in the tag , from a separate clock contained in the circuit of the invention . provide the logical state from the power good enable ( 900 ) is true , the sequence uses the clock signal to instruct the multiplexer to alternate connections from the analog - to - digital device ( 500 ) to the four different input voltages to the multiplexer . the sequencer signal is also used by the a / d device to coordinate the transfer of the digitized voltage outputs into the appropriate output channels for passage to the serializer . furthermore , the clock signal from the sequencer is also used by the serializer to coordinate the serialization of the difital bits corresponding to the four voltage inputs of the multiplexer . in the preferred embodiment , the output from the serializer can contain the four digitized values , each as a 16 - bit string , totaling 64 bits . the tag adds a unique id to the digital string prior to transmission to the receiver . in the preferred embodiment , the signal from the serializer is passed to the transponder tag and stored in its memory array . in the preferred embodiment , the tag transmits the content of its memory array to the receiver by modulating the incoming rf carrier signal . in the preferred embodiment , the rf signal received by the receiver is converted back to the digital string input to the tag from the serializer plus the digital value of the tag id itself . these two strings are sent from the receiver to a computer for further mathematical processing .
a system and method of determining a physiological state of a ruminant animal by monitoring the ph and temperature of the animal &# 39 ; s stomach . a battery - less , single unit sensor and transmitter is placed within the rumen or reticulum of the animal . ph and temperature measurements are taken and transmitted along with the animal identification code to a wireless receiver . the physiological state of the animal is determined using the mathematically analyzed ph and temperatures .