Tire Pressure Sensor (TPMS) Test Stand

In order to display data from a given sensor in test mode, it was proposed to create a unit of logical signal processing from the receiver. While it can receive signals of varying strengths from all sensors, it only processes and transmits the parameters of the sensor with the designated serial number over the network. We also provided the ability to change the sensor serial number over the network from the industrial controller. Thus, it is possible to reconfigure the unit to process signals from different sensors. However, this procedure takes some time, which was undesirable, so another option was proposed.

Since the customer wanted to simplify and speed up the process of testing the sensors, we modified the signal processing unit so that the receiver was placed in the screen at the place where the sensor is being tested. In addition, the receiver will be isolated from the main device. This is necessary so that it cannot receive signals from other sensors.

As a result of these modifications, the receiver will work only with one sensor, placed in a screened chamber. Reconfiguration of the unit will not be required.

Initially, the system was conceived as three independent units: a test chamber, an electronics unit, and a pneumatics unit.The test chamber was to be a cylindrical body with an inlet and outlet port and a radio receiver for transmitting data from the sensor. We used standard shut-off valves as the chamber. This solution is already designed for a pressure of up to 12 bar, and the design of a pressure vessel is a laborious task that requires additional efforts related to computer simulations.

To reduce chamber development costs, we repurposed water shutoff valves as the chamber itself. These valves are already designed to handle pressures up to 12 bar.

The electronics unit was to be located in a separate module and contain a programmable logic controller (PLC) and a power supply unit. The pneumatics unit, containing reducers, valves, and tubes for supplying and regulating air pressure in the test chamber, was also to be located in a separate unit. While this solution ensured safety in use, the dimensions of the stand were large, and the ergonomics did not satisfy the end user.

Therefore, we decided to combine the electronics and pneumatics units. We arranged the electronics and pneumatics in such a way that all requirements were met. All components in the pneumatic compartment comply with explosion-proof standards. The electronic compartment has a passive cooling system to protect against overheating. The solutions used allowed us to reduce the dimensions of the unit from 2 × 1.5 × 1 m to 0.7 × 0.78 × 0.36 m and make the device more convenient to use.

The control unit used a large number of screws, which reduced not only the aesthetic value of the device, but also its usability. The fasteners fixed the components of the case, i.e. the side, rear, bottom panels and the cover. The inconvenience in use was the need to unscrew the screws when opening the cover. We replaced these screws, which interfered with the monolithic design, with metal hinges inside the device. We welded the side, rear and bottom panels, and the cover, which acted as the front panel, was hung on hinges to this body. Thus, we managed to make the device monolithic and minimize external fasteners.