PRODUCE ITEM RIPENESS DETERMINATION
In some examples, a method is described. The method may include obtaining an electrical signal as an input signal. The method may also include generating a reference signal based on the input signal. Moreover, the method may include generating a device-under-test signal based on the input signal and based on a device-under-test capacitance between a first contact point and a second contact point. The first contact point may be electrically coupled to a first contact mechanism configured to contact a first contact area of the device-under-test. The second contact point may be configured to be electrically coupled to a second contact mechanism configured to contact a second contact area of the device-under-test. The method may also include generating a comparison signal based on a comparison between the reference signal and the device-under-test signal. Additionally, the method may include emitting an output signal that is based on the comparison signal.
1 . A measurement circuit, comprising:
an input circuit configured to obtain an electrical signal as an input signal;
a sensing circuit electrically coupled to the input circuit and configured to:
generate a reference signal based on the input signal; and
generate a device-under-test signal based on the input signal and based on a device-under-test capacitance between a first contact point of the sensing circuit and a second contact point of the sensing circuit, wherein the first contact point is electrically coupled to a first contact mechanism configured to contact a first contact area of a device-under-test and wherein the second contact point is configured to be electrically coupled to a second contact mechanism configured to contact a second contact area of the device-under-test;
a comparison circuit electrically coupled to the sensing circuit and configured to generate a comparison signal based on a comparison between the reference signal and the device-under-test signal; and
an output circuit electrically coupled to the comparison circuit and configured to emit an output signal that is based on the comparison signal.
2 . The measurement circuit of claim 1 , wherein:
the device-under-test includes a produce item;
the device-under-test capacitance is based on a ripeness of the produce item; and
the output signal indicates the ripeness of the produce item.
3 . The measurement circuit of claim 1 , wherein:
the comparison signal includes an alternating current (AC) signal; and
the output circuit is configured to convert the comparison signal from AC to direct current (DC) to generate the output signal.
4 . The measurement circuit of claim 1 , wherein the input signal includes an alternating current (AC) signal with a peak-to-peak voltage that is based on the device-under-test.
5 . The measurement circuit of claim 1 , wherein the input signal includes an alternating current (AC) signal with a frequency that is based on the device-under-test.
6 . The measurement circuit of claim 1 , wherein the sensing circuit includes:
a resistive element electrically coupled to a first node to which an output of the input circuit is coupled, wherein a resistance of the resistive element is based on the device-under-test;
a capacitive element electrically coupled between the resistive element and a ground of the measurement circuit, wherein a capacitance of the capacitive element is based on the device-under-test; and
a reference node between the resistive element and the capacitive element, wherein the reference signal is output by the sensing circuit at the reference node.
7 . The measurement circuit of claim 1 , wherein the sensing circuit includes:
the first contact point electrically coupled to a device-under-test node, wherein the device-under-test signal is output by the sensing circuit at the device-under-test node;
a resistive element electrically between the device-under-test node and a first node to which an output of the input circuit is coupled, wherein a resistance of the resistive element is based on the device-under-test; and
the second contact point electrically coupled to a ground of the measurement circuit.
8 . A measurement system comprising:
a contact system including:
a first contact mechanism configured to contact a produce item at a first contact area of a surface of the produce item, wherein the first contact mechanism is electrically conductive and is configured such that a size of the first contact area in contact with the first contact mechanism changes according to a ripeness of the produce item;
a second contact mechanism configured to contact the produce item at a second contact area of the surface of the produce item, wherein the second contact mechanism is electrically conductive; and
a measurement circuit including a first contact point electrically coupled to the first contact mechanism and including a second contact point electrically coupled to the second contact mechanism, wherein the measurement circuit is configured to generate an output signal based on an electrical property between the first contact point and the second contact point.
9 . The measurement system of claim 8 , further comprising a computing system communicatively coupled to the measurement circuit and configured to determine the ripeness of the produce item based on the output signal of the measurement circuit.
10 . The measurement system of claim 8 , wherein the first contact mechanism includes:
an electrically conductive ball; and
a deployment mechanism configured to press the electrically conductive ball against the surface of the produce item.
11 . The measurement system of claim 10 , further comprising an insulative guard ring disposed around the electrically conductive ball, wherein the insulative guard ring is configured to contact the surface of the produce item.
12 . The measurement system of claim 8 , wherein the first contact mechanism includes an electrically conductive roller configured to support at least a portion of the produce item such that a weight of the produce item presses the surface of the produce item against the electrically conductive roller.
13 . The measurement system of claim 8 , wherein the first contact mechanism includes an electrically conductive roller and a plurality of insulative rings disposed around the electrically conductive roller.
14 . The measurement system of claim 8 , wherein the measurement circuit further includes:
an input circuit configured to obtain an electrical signal as an input signal;
a sensing circuit electrically coupled to the input circuit and configured to:
output a reference signal based on the input signal; and
output a device-under-test signal based on the input signal and based on a device-under-test capacitance between the first contact point and the second contact point;
a comparison circuit electrically coupled to the sensing circuit and configured to generate a comparison signal based on a comparison between the reference signal and the device-under-test signal; and
an output circuit electrically coupled to the comparison circuit and configured to generate the output signal based on the comparison signal.
15 . The measurement system of claim 14 , wherein the input signal includes an alternating current (AC) signal with a peak-to-peak voltage that is based on the produce item.
16 . The measurement system of claim 14 , wherein the input signal includes an alternating current (AC) signal with a frequency that is based on the produce item.
17 . The measurement system of claim 14 , wherein the sensing circuit includes:
a resistive element electrically coupled to a first node to which an output of the input circuit is coupled, wherein a resistance of the resistive element is based on the produce item;
a capacitive element electrically coupled between the resistive element and a ground of the measurement circuit, wherein a capacitance of the capacitive element is based on the produce item; and
a reference node between the resistive element and the capacitive element, wherein the reference signal is output by the sensing circuit at the reference node.
18 . The measurement system of claim 14 , wherein the sensing circuit includes:
the first contact point electrically coupled to a device-under-test node, wherein the device-under-test signal is output by the sensing circuit at the device-under-test node;
a resistive element electrically between the device-under-test node and a first node to which an output of the input circuit is coupled, wherein a resistance of the resistive element is based on the produce item; and
the second contact point electrically coupled to a ground of the measurement circuit.
19 . A method comprising:
obtaining an electrical signal as an input signal, wherein the input signal includes an alternating current (AC) signal with one or more of the following based on a device-under-test: a peak-to-peak voltage and a frequency;
generating a reference signal based on the input signal; and
generating a device-under-test signal based on the input signal and based on a device-under-test capacitance between a first contact point and a second contact point, wherein the first contact point is electrically coupled to a first contact mechanism configured to contact a first contact area of the device-under-test and wherein the second contact point is configured to be electrically coupled to a second contact mechanism configured to contact a second contact area of the device-under-test;
generating a comparison signal based on a comparison between the reference signal and the device-under-test signal; and
emitting an output signal that is based on the comparison signal.
20 . The method of claim 19 , wherein the device-under-test includes a produce item and the method further comprises determining a ripeness of the produce item based on the output signal.