A kit of parts comprising: a tyre pressure sensor module (100, 700, 730) for fitting to a valve of a pneumatic tyre, the tyre pressure sensor module (100, 700, 730) comprising: an antenna configured to detect a short range telecommunications signal from a mobile electronic device (102, 300) over a distance of up to 4 cm, the antenna further configured to obtain, from the short range telecommunications signal through induction, electrical power sufficient to allow measurement of a pressure of a fluid within the pneumatic tyre and transmission of data indicative of the measured pressure to the mobile electronic device (102, 300); a receiver configured to receive the short range telecommunications signal, which comprises instructions to obtain a pressure reading; a pressure sensor configured to measure the pressure of the fluid within the pneumatic tyre; and a transmitter configured to transmit data indicative of the measured pressure to the mobile electronic device (102, 300) using a short range telecommunications signal over a distance of up to 4 cm; and a locating feature for securing to a housing of a mobile electronic device (102, 300) and configured to provide an indication to a user of the mobile electronic device (102, 300) when a transmitter and/or receiver of the mobile electronic device (102, 300) are located within 4 cm or less of the tyre pressure sensor module (100, 700, 730). a tyre pressure sensor module (100, 700, 730) for fitting to a valve of a pneumatic tyre, the tyre pressure sensor module (100, 700, 730) comprising: an antenna configured to detect a short range telecommunications signal from a mobile electronic device (102, 300) over a distance of up to 4 cm, the antenna further configured to obtain, from the short range telecommunications signal through induction, electrical power sufficient to allow measurement of a pressure of a fluid within the pneumatic tyre and transmission of data indicative of the measured pressure to the mobile electronic device (102, 300); a receiver configured to receive the short range telecommunications signal, which comprises instructions to obtain a pressure reading; a pressure sensor configured to measure the pressure of the fluid within the pneumatic tyre; and a transmitter configured to transmit data indicative of the measured pressure to the mobile electronic device (102, 300) using a short range telecommunications signal over a distance of up to 4 cm; and an antenna configured to detect a short range telecommunications signal from a mobile electronic device (102, 300) over a distance of up to 4 cm, the antenna further configured to obtain, from the short range telecommunications signal through induction, electrical power sufficient to allow measurement of a pressure of a fluid within the pneumatic tyre and transmission of data indicative of the measured pressure to the mobile electronic device (102, 300); a receiver configured to receive the short range telecommunications signal, which comprises instructions to obtain a pressure reading; a pressure sensor configured to measure the pressure of the fluid within the pneumatic tyre; and a transmitter configured to transmit data indicative of the measured pressure to the mobile electronic device (102, 300) using a short range telecommunications signal over a distance of up to 4 cm; and a locating feature for securing to a housing of a mobile electronic device (102, 300) and configured to provide an indication to a user of the mobile electronic device (102, 300) when a transmitter and/or receiver of the mobile electronic device (102, 300) are located within 4 cm or less of the tyre pressure sensor module (100, 700, 730).