Other Parts Discussed in Thread: PGA460, PGA460-Q1,
Can I use the PGA450 to detect an object closer than 20cm?
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Hi Tomek,
For objects closer than 20cm in distance, I recommend that you use the newer PGA460 with a high-frequency transducer (180-480kHz). The PGA450 is more suitable for transducers used in long range applications (30cm-5m typical) due to it only being able to support low-frequency transducers (39-70kHz).
Ok, but is any chance to detect ice/dirt on transducer or detect (not to measure distance) obstacle below 40cm ?
Hi Jakub,
Yes, it is possible to detect if a foreign substance is covering/blocking the transducer. The PGA460 includes built-in system diagnostics to measure the transducer frequency and decay time. In the event the transducer is covered with ice or mud, the resonant frequency during decay and decay time of the transducer will change, which will be reflected in the results of the system diagnostics.
The question is about the PGA450 (with 40khz transducer), because the sensor has a built-in LIN transceiver, so could you tell me how I can measure this change in transducer frequency and decay time. Have you tested it? And the main problem of this sensor is the dead zone, if the obstacle is below 40 cm, we can not see it, and this defect completely ruins the PGA450 as a automotive parking assistant.
Hi Jakub,
The PGA450-Q1 does not include the same system diagnostic features as the PGA460-Q1. We are aware that the PGA450-Q1 suffers from a long dead zone, where you can only reliably detect downwards of about 30cm. The PGA450-Q1 only includes a decay diagnostic.
The newer PGA460-Q1 includes a built-in One-Wire UART transceiver, which is similar to LIN, so if you are looking for a simplified LIN alternative, then the PGA460's OWU is the best option.
Depending on your maximum range, you can also try changing your transducer to a higher frequency on the PGA450-Q1 (i.e. 70kHz instead of 40kHz) to better enable short range performance for your park assist application. 40kHz is good is you need upwards of 5m, but 70kHz will still be good for up to at least 3m.