One solution is the use of a wireless range extender. But not a run off the mill range extender. The project required a powerful outdoor type (27 dBm transmission power) to cover the whole plant in any weather condition. I decided to shop around, and found that the best range extender for the client is TP Link's TL WA7210N, due to its compatibility with the client's current wireless router, which I would find out later on is irrelevant. Since this was the first time we were going to cover an area this large, and the fact that I have no track record in using a range extender, I begged for time to finish the project.
Initially, to keep the setup simple, I wirelessly connected the main router to the range extender with the main router sitting behind a wall on the second floor office, and the range extender standing downstairs 2 meters off the ground, and around 30 meters away, no line of sight due to the wall.
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| Option 1:Range Extender mode 30 meters away without line of sight due to wall (pink Cleverdog is our sample unit) |
However, we noticed that devices were having a hard time connecting to the range extender only after a few hours. The devices connecting to the range extender were not being given IP addresses. The workaround to the problem was to have someone just unplug/replug the range extender when this issue occurred. However, this is an unacceptable solution. Fortunately, I was able to recreate the problem with approximate conditions at home using a TP Link TL WR841N as a main router, and an old TP Link TL WR740N configured as a range extender. At home, I was able to concentrate in finding a solution than I would have been at the client's plant.
The problem, apparently, was that the range extender itself was getting disconnected from the main router, because the signal it received was too weak given their placements. The range extender required nearly full signal strength from the main router for it to work reliably. Two out of four bars will not do. A constant three to four bars (signal percent 80%, @RSSI range of 30 should be above 15dBm) of main router signal was required to avoid disconnection from the main router.
Upon consultation with the client, we decided to experiment with a wired setup with the range extender acting as an access point connected to the main router. The experiment proved to offer a reliable connection, but since a short network cable was used, and the access point was placed just at an office window, the coverage was dismal. Cleverdog cameras at the far end of locations #3, and #4 were not able to connect. But the experiment showed that if the placement of the wired access point was improved, robust coverage can be achieved. The next challenge was to select the best location of the access point.
A truss supporting roofing on an i beam post 17 meters away from the main router was selected.
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| Option 2: Wired access point mode |
The next challenge was wiring the access point from this location to the main router. Luckily, the ceiling where the main router is situated has overhangs installed for the legacy security camera wires. These overhangs were used to route the cable from the main router to the access point. Total network cable length was 24 meters, which is well below the 100 meter limit for Cat5E.
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| 24 meters cabling |
Special mention to cabling practice must be mentioned here: color sequence as prescribed by T568A Straight Through Ethernet Cable must be strictly followed. I had the displeasure of debugging unstable connection for a considerable amount of time, because I followed my own color sequence. My theory is that since the Cat5E cable I used was unshielded, and more than 5 meters long, interwire noise becomes a critical factor in establishing connection. I followed my own convention in the experimental stage, and it worked, but that instance used a shorter cable, in which noise would not have been an issue. Another thing to note was our commitment to stick to a wired solution. The distance of the access point's placement from the main router (17 meters) was half compared to its former location when it was a range extender (30 meters). At this distance, I think a wireless solution (range extender) would be simpler, since no cabling is required. However, we stuck with the wired access point option as we deemed it to be more robust, and reliable. Should the range extender option fail again, it is absolutely unacceptable for the client's staff to climb up 15 meters to the device just to reboot it.
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Access Point mount (rear)
Access Point mount (front, zoomed) |
After fixing that problem, connection was established, and Cleverdog IP cameras went online. The client can now monitor his business 24/7, and as an added bonus, the whole plant is now wifi enabled. Another inventory tracking project commissioned by the client that requires connection of Android phones to a central server in his office is facilitated by this improvement in the plant's IT infrastructure.
Postscript:
In retrospect, I could have ordered a higher spec wireless access point rather than TP Link's TL WA7210N. I ordered this model, because I thought its compatibility with the client’s router would be an important requirement. However, we went for a wired solution, so its wireless compatibility with the main router (2.4GHz, 150Mbps) became irrelevant. I should have chosen a 5GHz, 300Mbps model instead.
The client's two legacy 16 channel CCTV camera systems cost roughly P176,400.
DVR with 500GB HDD P25,000
16 CCTV cameras P1,450 x 16 = P23,200
Installation for a 1 ha. plant (transportation, labor, cable, equipment) P40,000
Total P88,200 each
The same number of Cleverdog IP cameras costs:
Cleverdog IP camera P1,700 x 32 = P54,400
Outdoor Wireless Access Point P4,000 (from PC Options)
MicroSD card P500 x 32 = P16,000 (optional)
Installation P0 (client had his own maintenance staff set up the cables)
Total P74,400 excluding internet related costs (subscription, router), and cabling
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| Client's total device package excluding cabling, which he provided |
Both systems have their innate advantages, and disadvantages, so it is up to the user to decide whether the trade offs justify the cost. The two approaches are not mutually exclusive as proven by our client having both systems with fewer Cleverdog cameras than legacy ones, but placed in critical areas where he prefers on demand monitoring.
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