A deformation sensing apparatus comprising: an elastic substrate comprising a flexible, electrically-insulating dielectric material; a first strain-gauge element formed on a first surface (130-a) of the elastic substrate , the first strain-gauge element having two distinct terminals, a first terminal (110-a) and a second terminal (110-b), and configured to output a first signal in response to a strain applied in a first direction, wherein the first signal is measurable across the first and second terminals (110-a, 110-b) of the first strain-gauge element ; a second strain-gauge element formed on a second surface of the elastic substrate opposite to the first surface, the second strain-gauge element having two distinct terminals, a third terminal (120-a) and a fourth terminal (120-b) and configured to output a second signal in response to a strain applied in the same first direction, wherein the second signal is measurable across the third and fourth terminals (120-a, 120-b) of the second strain-gauge element ; wherein the deformation sensing apparatus is configured to output a third signal responsive to an applied deformation, the third signal being measurable between a terminal of the first strain-gauge element and a terminal of the second strain-gauge element ; a measurement circuit configured to measure the first signal from the first strain-gauge element , the second signal from the second strain-gauge element , and the third signal, in response to the applied deformation; and a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the sensing apparatus , in the applied deformation, based on the measured first signal from the first strain-gauge element , the measured second signal of the second strain-gauge element , and the third signal. an elastic substrate comprising a flexible, electrically-insulating dielectric material; a first strain-gauge element formed on a first surface (130-a) of the elastic substrate , the first strain-gauge element having two distinct terminals, a first terminal (110-a) and a second terminal (110-b), and configured to output a first signal in response to a strain applied in a first direction, wherein the first signal is measurable across the first and second terminals (110-a, 110-b) of the first strain-gauge element ; a second strain-gauge element formed on a second surface of the elastic substrate opposite to the first surface, the second strain-gauge element having two distinct terminals, a third terminal (120-a) and a fourth terminal (120-b) and configured to output a second signal in response to a strain applied in the same first direction, wherein the second signal is measurable across the third and fourth terminals (120-a, 120-b) of the second strain-gauge element ; wherein the deformation sensing apparatus is configured to output a third signal responsive to an applied deformation, the third signal being measurable between a terminal of the first strain-gauge element and a terminal of the second strain-gauge element ; a measurement circuit configured to measure the first signal from the first strain-gauge element , the second signal from the second strain-gauge element , and the third signal, in response to the applied deformation; and a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the sensing apparatus , in the applied deformation, based on the measured first signal from the first strain-gauge element , the measured second signal of the second strain-gauge element , and the third signal. <EOS>