Park sensor installation

klemens_TSG
Posts: 12
Joined: Tue May 08, 2018 8:34 am
Company: Thuega SmartService

Park sensor installation

Post by klemens_TSG » Tue May 08, 2018 10:00 am

Dear all,

we have purchased 10 parking sensors which were tested successfully during a field test on the road with a standard passenger car.

The parking sensors were then deployed (surface-mounted) on a road (spacing between the sensors: 4 m) but without using the delivered anti-vandalic screws and anchors as the required special torx bit was not available at short.
Instead we used standard screws and anchors.

Now we observe that only 3 parking sensors are working nominally, 7 sensors stay in state "free" when a vehicle is parked above them.
Can the use of the non-nominal screws effect the sensor's sensitivity in such a way that it could explain the observed behaviour of our "sensor chain" ?

Thanks,
Klemens

libelium-dev
Posts: 27967
Joined: Mon Sep 28, 2009 1:06 pm

Re: Park sensor installation

Post by libelium-dev » Wed May 09, 2018 8:48 am

Hi,

If the installation of the node isn't correct, the node could be damaged due to water ingress. But we think that the screws don't affect the parking status.

Could you share with us the data receive in the back-end? What sleep time did you set? Could you try to set 1 minute?

Did you set the nodes in this position?
http://www.libelium.com/downloads/docum ... df#page=54

Regars

klemens_TSG
Posts: 12
Joined: Tue May 08, 2018 8:34 am
Company: Thuega SmartService

Re: Park sensor installation

Post by klemens_TSG » Wed May 09, 2018 11:29 am

Hi,

the sleep time is already set to 1 minute and the parking sensors were installed as described in the technical guide w.r.t. to the mounting within a single parking slot.
But in contrast to the side-by-side sensor mounting for parallel parking slots in our application the sensors are mounted on a road in one single row with a spacing of 4 meters in between.

Currently we use Firmware Version 2.0.1 without Callback Server and without RSSI feature.
As the receive data to be shared are stored in a database and are extracted via query: Which data do you need for your analysis ?

Kind regards

libelium-dev
Posts: 27967
Joined: Mon Sep 28, 2009 1:06 pm

Re: Park sensor installation

Post by libelium-dev » Thu May 10, 2018 8:57 am

Hi,

Are the slots delimited? The parking slots must be delimited by lines and the node must be located in the centre of the delimiter slot to detect cars properly.

We would like to know a couple of frames before and after that the node was blocked.

Regards

klemens_TSG
Posts: 12
Joined: Tue May 08, 2018 8:34 am
Company: Thuega SmartService

Re: Park sensor installation

Post by klemens_TSG » Thu May 17, 2018 2:39 pm

Hi,

as already mentioned, the parking sensors are mounted in row on a road without delimited slots.
Hence it is not generally ensured that a sensor is centered under the car when the car stops.
Nevertheless all sensors should return to occupy state "free" at least at night as for our application holds that during night time there are de facto no cars crossing the parking sensors.

The attached frames received by or LoRa-Network-Server belong to Parksensor Nr.9 which at first worked normally and finally freezed with state "Occupied".
(Remark: Each frame is labelled with the corresponding time stamp)

Regards

2018-05-15 09:31:36
{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff29392a",
"rssi" : -114,
"loRaSNR" : 4.8,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293837",
"rssi" : -119,
"loRaSNR" : -2.8,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293885",
"rssi" : -121,
"loRaSNR" : -11.2,
"name" : "Gateway-3",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868100000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 204,
"fPort" : 2,
"data" : "AcgVIhcFTv25Cms="
}

2018-05-15 09:45:36

{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff29392a",
"rssi" : -113,
"loRaSNR" : -4,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293837",
"rssi" : -116,
"loRaSNR" : -6.2,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868300000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 205,
"fPort" : 2,
"data" : "gMkYBxcGTf2dAMg="
}


2018-05-15 10:09:37

{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff29392a",
"rssi" : -119,
"loRaSNR" : -0.2,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293837",
"rssi" : -119,
"loRaSNR" : -1.5,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868100000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 206,
"fPort" : 2,
"data" : "AMoYBiP7mQjjAMc="
}


2018-05-15 10:10:37

{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff293837",
"rssi" : -112,
"loRaSNR" : -3,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff29392a",
"rssi" : -113,
"loRaSNR" : -5.5,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868300000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 207,
"fPort" : 2,
"data" : "gMsYBTD9iwpJAMc="
}

2018-05-15 12:10:38

{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff29392a",
"rssi" : -109,
"loRaSNR" : 3.2,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293837",
"rssi" : -113,
"loRaSNR" : 2.2,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293885",
"rssi" : -119,
"loRaSNR" : -13.5,
"name" : "Gateway-3",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868500000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 208,
"fPort" : 2,
"data" : "gcwADRkFM/2OCjM="
}

2018-05-15 14:10:39

{
"applicationID" : "13",
"applicationName" : "TestApp",
"nodeName" : "Libelium-Parksensor09",
"devEUI" : "0004a30b001ff569",
"rxInfo" : [ {
"mac" : "c0ee40ffff29392a",
"rssi" : -111,
"loRaSNR" : 4.5,
"name" : "Gateway-1",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293837",
"rssi" : -119,
"loRaSNR" : -0.8,
"name" : "Gateway-2",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
}, {
"mac" : "c0ee40ffff293885",
"rssi" : -121,
"loRaSNR" : -14.8,
"name" : "Gateway-3",
"latitude" : 0,
"longitude" : 0,
"altitude" : 0
} ],
"txInfo" : {
"frequency" : 868100000,
"dataRate" : {
"modulation" : "LORA",
"bandwidth" : 125,
"spreadFactor" : 12
},
"adr" : true,
"codeRate" : "4/5"
},
"fCnt" : 209,
"fPort" : 2,
"data" : "gc0CDSoGIfvIB78="
}

jot4p
Posts: 192
Joined: Thu Apr 21, 2016 5:19 pm

Re: Park sensor installation

Post by jot4p » Thu May 17, 2018 3:06 pm

Hi,

The position of libelium logo it's very important.. this fix my problems...

PAG 54
http://www.libelium.com/downloads/docum ... _guide.pdf

libelium-dev
Posts: 27967
Joined: Mon Sep 28, 2009 1:06 pm

Re: Park sensor installation

Post by libelium-dev » Fri May 18, 2018 10:05 am

Hi,

The parking nodes were designed to work in delimiter slots, we can't ensure it functionality in non delimiter slots. When a car doesn't park just over a node, it's likely that it won't detect when it is free and it should be reset to work again.

Regards

klemens_TSG
Posts: 12
Joined: Tue May 08, 2018 8:34 am
Company: Thuega SmartService

Re: Park sensor installation

Post by klemens_TSG » Wed May 23, 2018 1:03 pm

Hi,
I'm not quite sure whether I have correctly understood your argumenation:
If a car doesn't park just over a (calibrated) node then I would rather guess that there is a high probability that the sensor doesn't detect the "Occupied"-state and, hence, would stay in state "Free".
Our case is vice-versa: the node doesn't detect that a car has left the area around the node and therefore stays in state "Occupied" even when most of the possible sources of magnetic disturbances may have disappeared (for example at night).

Does the node show something like a hysteresis for the state changes Free > Occupied and Occupied > Free ?
In other words: Is a different (lower ?) magnetic field signal strength required to bring a node (back) into state "Free" compared to the calibration signal strength ?

Thanks

libelium-dev
Posts: 27967
Joined: Mon Sep 28, 2009 1:06 pm

Re: Park sensor installation

Post by libelium-dev » Thu May 24, 2018 9:39 am

Hi,

The parking nodes are more sensitive to set occupied state than empty state. This means that if a car doesn't park just over a node, it will surely detect the car and will change its status to occupied but it won't detect when the parking slot was empty. As we said, the parking nodes were designed to work in delimiter slots.

Regards

klemens_TSG
Posts: 12
Joined: Tue May 08, 2018 8:34 am
Company: Thuega SmartService

Re: Park sensor installation

Post by klemens_TSG » Thu Jun 07, 2018 9:21 am

Hi,

besides the problem that the 10 park sensors are frozen in state "Occupied" a few hours after a reset we have detected another problem:
- 3 of the 10 installed sensors are completely offline since several days, i.e. we get no regular KEEPALIVE packages (12 per day) any longer.
- From another sensor we now receive KEEPALIVE and RESERVED packets alternately every two hours.

Is this behaviour an indication for a hardware failure ?
Can we wake up the sensors via cold reset, i.e. by disconnecting the power supply ?

Independently from this we think about a workaround to cope with the "frozing state"-Problem:
As the planned application will be in operation only for a few hours per day a principal solution could be a periodic reset of the sensors once per day at a definite time (for example at midnight) via downlink command of the Callback server.

Could that be a feasible solution ?

Regards,
Klemens

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