CN102637370B - Stall detection system based on wireless sensor network - Google Patents

Abstract

A parking space detection system based on a wireless sensor network, which is used to detect the use status of parking spaces in a parking area, is characterized in that it includes: parking space detection nodes distributed in the parking area and corresponding to the number of parking spaces, when the state of the parking spaces changes The position computer sends the parking space status data. The above-mentioned parking space detection system based on wireless sensor network only sends data to the upper computer when the state of the parking space changes, so when the data is not sent, the parking space detection node is in the standby state. Therefore, the parking space that can be in the standby state intermittently is used Probe nodes, save energy. The parking space detection system based on wireless sensor network uses wireless sensor network to realize data transmission, so it only needs to control the wireless network for transmission to realize the maintenance of the system.

Description

Parking space detection system based on wireless sensor network

technical field

The invention relates to a parking space detection system, in particular to a parking space detection system based on a wireless sensor network.

Background technique

With the rapid development of my country's economy, urban development is advancing by leaps and bounds. People's yearning for urban life is getting stronger and stronger, so more and more people are gradually gathering in cities. Due to the continuous improvement of people's living standards, car consumption has also become a hot spot for people's consumption, and the per capita car ownership is also increasing. The urban land area is limited, the per capita land is insufficient, the urban planning is relatively lagging behind, the parking lacks unified management and scheduling, the parking information is not public enough, and the parking is not intelligent enough.

Therefore, it can be seen from the above problems that for my country, a country with a large population and a serious shortage of land per capita, problems such as urban traffic congestion, parking difficulties, and driving difficulties are becoming increasingly prominent. Most of the existing parking space detection systems are wired, which brings problems such as high operation and maintenance costs and high energy demand, which also limits their popularization and application.

Contents of the invention

Based on this, a wireless sensor network-based parking space detection system with simple maintenance and energy saving is provided.

A parking space detection system based on a wireless sensor network, which is used to detect the use status of parking spaces in a parking area, including: parking space detection nodes distributed in the parking area and corresponding to the number of parking spaces, sending a parking space to the upper computer when the state of the parking space changes status data.

In one of the embodiments, the parking space detection system further includes a node controller disposed on the parking space detection node and used to control the switching between the working state and the standby state of the parking space detection node.

In one embodiment, the node controller is a strong magnetic device, and the strong magnetic device is attached above the parking space detection node.

In one embodiment, the node controller outputs signals with a maximum value and a minimum value, so as to respectively control the parking space detection node to enter a standby state and a working state.

In one of the embodiments, the parking space detection node adopts an adaptive sampling mechanism, specifically:

When the parking space detection node detects that the magnetic signal change exceeds the threshold, the sampling period is set to the first sampling period T ₂ ;

When the parking spot detection node detects that the change of the magnetic signal is not greater than the threshold value, the sampling period is set to the second sampling period T ₁ , wherein both T ₁ and T ₂ are preset sampling periods, and T ₁ is several times longer than T ₂ .

In one of the embodiments, it also includes a routing node and a gateway node for network communication, and the parking space detection node sends the parking space state data to the upper computer through the routing node and the gateway node; the parking space detection node is at least connected with More than two routing nodes are connected, and the routing nodes are connected point-to-point with the gateway node, and the downlink data transmission from the gateway node to the parking space detection node adopts flooding.

In one of the embodiments, the parking space detection node transmits data to multiple routing nodes within a hop range by using an acknowledgment retransmission mechanism.

In one of the embodiments, when the routing node receives the parking space status data transmitted by the parking space detection node, it transmits the parking space status data to the gateway node through a hop-by-hop confirmation mechanism.

In one of the embodiments, the gateway node and the routing node sleep and wake up regularly.

In one of the embodiments, it is characterized in that the routing node is provided with a solar cell module for powering the router.

The above-mentioned parking space detection system based on wireless sensor network only sends data to the upper computer when the state of the parking space changes, so when the data is not sent, the parking space detection node is in the standby state. Therefore, the parking space that can be in the standby state intermittently is used Probe nodes, save energy. The parking space detection system based on wireless sensor network uses wireless sensor network to realize data transmission, so it only needs to control the wireless network for transmission to realize the maintenance of the system.

Description of drawings

Fig. 1 is a schematic structural diagram of a parking space detection system based on a wireless sensor network;

Figure 2 is a schematic diagram of the communication between the parking space detection node and the host computer.

Detailed ways

As shown in Figure 1, it is a schematic structural diagram of a parking space detection system based on a wireless sensor network. The parking space detection system based on the wireless sensor network is used to detect the use status of the parking spaces in the parking area, including: the parking space detection nodes 20 distributed in the parking area and corresponding to the number of parking spaces, and sending the parking space status data to the host computer when the parking space status changes .

The parking space detection node 20 dynamically transmits sampling data. When the parking space detection node 20 detects that the state of the parking space changes from no car to car or from car to no car, the parking space status data is sent to the upper computer. The parking space detection node 20 does not transmit the detection data in real time, but processes the detection data locally to calculate the state information of whether there is a car or no car. For example, when the status of the parking space changes from no car to having a car, the parking space detection node 20 sends to the host computer that the status of the parking space is a car, and the host computer records the parking time. At this time, the status of the parking space is no car, and the host computer records the departure time. According to the parking time and departure time, the host computer can display the status information of the parking space in the garage, so as to achieve dynamic update, instead of sampling and transmitting the parking space detection node 20 all the time. Keeping the upper computer in a state of continuous updating, so that the processing capacity of the upper computer and the parking space detection node 20 can be reduced and energy can be saved.

The cycle of the parking space detection node 20 _in the process of dynamic transmission of sampling data is variable. Specifically, the threshold value is set to C _T . Sampling period T ₂ . When the parking space detection node 20 detects that the change of the magnetic signal is not greater than the threshold C _T , the sampling period is set as the second sampling period T ₁ . Both T ₁ and T ₂ are preset sampling periods, and T ₁ is greater than T ₂ . Generally, the sampling period of the parking space detection node is T ₁ , and T ₁ is a relatively long period of time, usually set between 3 and 10 seconds. And when it is detected that the change of the magnetic signal exceeds the threshold C _T , the sampling period _T1 to _T2 is shortened, and _T2 is usually set between 0.1 and 0.5 seconds. After a period of time with _T2 as the sampling period, the parking space detection node 20 To detect the change of the magnetic signal, if the threshold value C _T is not exceeded, the sampling period is set as T ₁ , and if the threshold value C _T is exceeded, the sampling period is set as T ₂ .

In this embodiment, assuming the sampling value S _i , the reference value B _i is calculated according to the following formula, where α is a smoothing parameter, which can be set to 0.05.

${\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ {\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.$

Set the threshold as C _T , and when |S _i -B _i |<=C _T , set the sampling period of the parking spot detection node as T ₁ , and T ₁ is a longer period of time, which can usually be set to 3 to between 10 seconds. When it is detected that the change of the magnetic signal exceeds the threshold C _T , that is, |S _i -B _i |>C _T , the parking space detection node shortens the sampling period and sets it to T ₂ , and T ₂ can usually be set between 0.1 and 0.5 seconds to T ₂ is the sampling period that lasts for a period of time T, and then check the change of the magnetic signal. If the change does not exceed the threshold C _T , set the sampling period as T ₁ .

In this embodiment, the parking space detection system further includes a node controller 10 disposed on the parking space detection node 20 for controlling the switching between the working state and the standby state of the parking space detection node 20 . The node controller 10 outputs signals with a maximum value and a minimum value to respectively control the parking space detection node 20 to enter a standby state and a working state.

Specifically, the node controller 10 is a strong magnetic device, and the strong magnetic device is attached above the parking space detection node 20 . When the value of the signal detected by the strong magnetic device alternates between the maximum value and the minimum value, the parking space detection node 20 is controlled to switch between the standby state and the working state. Under normal circumstances, the minimum value is 0, and the maximum value is 4096. When the detection signal value of the strong magnetic device is 0 or 4096, and 0 and 4096 appear alternately, the strong magnetic device will control the parking space detection node 20 to be in a straight line standby state and work. State transitions.

As shown in Figure 2, it is a schematic diagram of the communication between the parking space detection node and the host computer. The parking space detection node 20 sends the parking space status data to the upper computer through the routing node 30 and the gateway node 40 . The parking space detection node 20 is connected to at least two routing nodes 30, and the routing node 30 is connected point-to-point with the gateway node 40, and the downlink data transmission from the gateway node 40 to the parking space detection node 20 adopts flooding.

When the routing node 30 receives the parking space status data transmitted by the parking space detection node 20, it transmits the parking space status data to the gateway node 40 through a hop-by-hop confirmation mechanism.

The parking space detection node 20 transmits data to multiple routing nodes 30 within a hop range by using an acknowledgment retransmission mechanism. The parking space detection node 20 can communicate with multiple routing nodes within the neighbor range, and the reliability of uplink data transmission between the parking space detection node 20 and the gateway node 40 is enhanced through this redundant transmission mechanism. The parking spot detection node 20 transmits data to multiple routing nodes 30 within one hop using the confirmation retransmission mechanism, and usually selects 1 to 3 routing nodes 30 with the best communication quality from the routing table. A tree network is formed between the routing node 30 and the gateway node 40. The routing node of each data packet transmits the data to the gateway node 40 through the hop-by-hop confirmation mechanism. If the gateway node 40 receives duplicate data packets, it ignores them.

The downlink data transmission from the gateway node 40 to the parking space detection node 20 may use flooding. Flood routing is used for data transmission between gateway node 40 and routing node 30. All routing nodes 30 must save instruction information within 60 seconds. Parking space detection node 20 adopts a sleep mechanism and cannot receive data from routing node 30 in real time. The parking space detection node 20 is configured to obtain instruction information from the routing node 30 at a period of 20 seconds.

The host computer controls the timing sleep and wake-up of the gateway node 40 and the routing node 30 . Therefore, the parking space detection node 20 and the routing node 30 can use instructions to control timing sleep and wake-up. The command format is: T _sleep , T _wakeup . For example, the sleep instruction issued by the gateway node 40 is (1min, 480min), when the parking space detection node 20 and the routing node 30 in the network receive the instruction, they will go to sleep after 1 minute, and wake up after sleeping for 480 minutes . The parking space detection node 20 and the routing node 30 need to save variables and various configuration parameter values before going to sleep, such as threshold value, parking space status, adoption cycle and serial number, etc., and store the values of these parameters in non-volatile memory Among them, the values of these parameters need to be recovered before the parking space detection node 20 and the routing node 30 wake up.

The routing node 30 in all the above embodiments is provided with a solar battery module for powering the routing node.

In this embodiment, the parking space detection node 20 is in a standby state before being deployed to a parking space.

The above-mentioned parking space detection system based on the wireless sensor network uses a strong magnetic device to control the working state of the parking space detection node, which can make the parking space detection node intermittently in the standby state and save energy. The parking space detection node adopts an adaptive sampling mechanism, which can also reduce the workload of the parking space detection node, so as to achieve the purpose of energy saving. The parking space detection system based on wireless sensor network uses wireless sensor network to realize data transmission, so it only needs to control the wireless network for transmission to realize the maintenance of the system.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (9)

1. the parking place detecting system based on wireless sensor network, for unloading lot detection using state in parking area, it is characterized in that, comprise: be distributed in parking stall probe node in parking area and corresponding to parking stall quantity, send parking space state data when parking space state changes to host computer; Parking stall probe node dynamic transmission sampled data, parking stall probe node has car or from when having car to become without car from becoming without car detecting parking space state, parking space state data are sent to host computer, parking stall probe node is real-time Transmission detection data not, but detection data at processing locality, calculate the status information of a car or car free;

If sampled value S _i, according to following formulae discovery reference value B _i, wherein α is smoothing parameter,

$B_i=\left\{\begin{array}{cc}{S}_i& i=1\\ B_{i-1}\&times;(1-\mathrm{\&alpha;})+S_i\&times;\mathrm{\&alpha;}& i>1\end{array}\right.$

If threshold value is C _t, when | S _i– B _i| <=C _twhen, if the sampling period of parking stall probe node be set to T ₁; Threshold value C is exceeded when detecting magnetic signal change _ttime, namely | S _i– B _i| >C _t, then the parking stall probe node shortening sampling period is set to T ₂;

The cycle of described parking stall probe node in dynamic transmission sampled data process be change, described parking stall probe node adopts adaptively sampled mechanism, is specially, when described parking stall probe node detect magnetic signal change exceed threshold value C _ttime, then the sampling period is set to the first sampling period T ₂; When described parking stall probe node detect magnetic signal change be not more than threshold value C _ttime, then the sampling period is set to the second sampling period T ₁, wherein T ₁and T ₂be the default sampling period, and T ₁be greater than T ₂.

2. the parking place detecting system based on wireless sensor network according to claim 1, it is characterized in that, described parking place detecting system also comprises to be located on the probe node of described parking stall, for the Node Controller of the conversion of the duty and holding state that control parking stall probe node.

3. the parking place detecting system based on wireless sensor network according to claim 2, is characterized in that, described Node Controller is strong magnetic machine, and described strong magnetic machine is attached at above the probe node of parking stall.

4. the parking place detecting system based on wireless sensor network according to claim 2, is characterized in that, described Node Controller exports the signal with maximal value and minimum value, enters holding state and duty to control described parking stall probe node respectively.

5. the parking place detecting system based on wireless sensor network according to claim 1, it is characterized in that, also comprise the routing node for network service and gateway node, described parking stall probe node sends parking space state data by described routing node and described gateway node to host computer; Described parking stall probe node is at least connected with plural routing node, described routing node and described gateway node point to point connect, and described gateway node adopts inundation to the downlink data transmission of described parking stall probe node.

6. the parking place detecting system based on wireless sensor network according to claim 5, is characterized in that, described parking stall probe node adopts and confirms that retransmission mechanism is transferred to data the multiple routing nodes within the scope of one jumping.

7. the parking place detecting system based on wireless sensor network according to claim 5, it is characterized in that, when described routing node receives the parking space state data of described parking stall probe node transmission, by hop-by-hop affirmation mechanism, parking space state data are transferred to gateway node.

8. the parking place detecting system based on wireless sensor network according to claim 5, is characterized in that, described gateway node, routing node timing dormancy and wake up.

9. the parking place detecting system based on wireless sensor network according to claim 5 to 8 any one, is characterized in that, described routing node is provided with the solar module of powering for routing node.