Construction sites, festivals, markets and emergency scenes all need video surveillance, often within days or hours, and usually where there is no network to plug into. Trenching cable for a site that will look different next month, or disappear after the event, rarely makes sense.
What makes temporary sites hard
- No existing network or power at the camera positions
- Layouts that change as buildings rise or stalls move, blocking line of sight
- Short deadlines, often with work allowed only at certain times
- Crowds, traffic and electrical interference from generators and equipment
- Everything has to come down again, or move to the next site
Why a wireless mesh suits them
Anywhere nodes mount on temporary poles, scaffolding, cranes or buildings, and PoE carries power and data to each camera over one cable. Where there is no mains supply, cameras and nodes can run on solar power. Because every node can reach more than one neighbour, the mesh routes around a blocked path, and a ring design keeps video flowing if a link fails. When the job ends, the equipment comes down and goes to the next site.
Events: Geylang Serai Bazaar, Singapore
The month-long Hari Raya bazaar needed surveillance for crowd management and traffic control. A 5-hop wireless mesh was built along a 1 km road on temporary roadside poles, carrying PTZ HD cameras back to the command centre despite heavy interference from stalls and generators. It was deployed within one day and removed after the event.
Construction: King Abdul Aziz Road, Makkah
On a construction site where line of sight kept changing, four solar-powered wireless mesh rings connect 60 full HD cameras at up to 28 outdoor locations. Each location only needs line of sight to the next, and two offload points per ring at the data centre remove any single point of failure.
Construction: Akademiska Hospital, Sweden
Video surveillance for a hospital construction site went from setup and training to deployment in less than 12 hours, using a 5-hop mesh ring on poles and rooftops with no clear line of sight from the control room.
Emergencies
Wireless coverage can also be set up on portable power at an incident scene. Hong Kong Police’s Disaster Victim Identification Unit has used temporary wireless coverage, set up within 15 minutes, to send information from officers’ tablets to a registration database.
More than cameras
The same network can carry access control, public address, IoT gateways and Wi-Fi access points, so a construction site or event runs one network instead of several. On a construction site, the network can be extended as the building grows taller.
Planning checklist
- Where will cameras go, and where can nodes be mounted with a view to the next node?
- Is mains power available, or will cameras and nodes need solar power?
- How many cameras, at what resolution, and how will that grow?
- Where is the control room or recorder, and is there a wired connection to drop the traffic off?
- How quickly must it be running, and how will it be moved or removed afterwards?