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Topic: JSN-SR04T ultrasonic custom sensor unit (Read 170 times) previous topic - next topic


Jul 26, 2020, 10:49 pm Last Edit: Jul 26, 2020, 10:53 pm by NadJ
Would you kind folk please sanity check my idea and throw in some caution, ideas and suggestions for me?

I am trying to build an outdoor ultrasonic sensor unit   that can transmit range sensing data over a long distance (30m / 100ft). It will be connected to a Windows PC. This will become part of a home perimeter security system. I.e. If someone is hovering outside my window bay I want to be alerted. I strongly feel ultrasonic range detection is the best choice for me given my windows and how a would be burglar would reach them. Have considered PIR.

Picture an outdoor junction box like this: https://images.app.goo.gl/fefhusZ9xqBZxDw96

...with weatherproof ultrasonic sensors pointing outwards (obviously). The box will be mounted to a wall just beneath my window bays.

The sensor and PCB I'm looking at is the JSN-SR04T: https://www.amazon.co.uk/dp/B07MKQ7VQF/ref=cm_sw_r_cp_apa_i_q2zhFbSJ2F8QP

After some research, I have learned that for long distance I need to make sure the data is serialized? locally (near the sensor) and then the serial data transmitted over wire to an Arduino (instead of an analogue output being transmitted over long distance). I believe the JSN-SR04T can do this, but can it do it out of the box? The data sheet is in Chinglish and a bit difficult to understand.

Ideally I want 3 sensors, let's say 2 inches apart. I want to cater for redundancy and false returns. I want 2 out of 3 sensors to give the same range before I act on the signal. Immediately, I can think of cross talk problems? Is that a thing given these sensors and the 2in separation?

As an alternative to Arduino, I'm looking at the option to simply (or not) have the analog outputs from each PCB go straight into a POE based Ethernet DAQ or PLC that is local to the sensors. I would then use the Modbus protocol to query my module straight from within my application running on my PC over the CAT5 cable connected to the DAQ/PLC. Would this be a better way to do? Any suggestions at all massively appreciated.


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