Remote Farm camera – experimenting with WiFi

Clive from the Raspberry Pi Foundation very kindly let us have a Pi Model A and camera, so it’s time to take this project forward a stage. At the moment the alpha test version is in service keeping an eye on our new piglets. Although the original purpose was to keep an eye on our newly arrived cattle pigs are more enterprising, so it’s good to know where they are

Development was stalled however since it’s not easy to work on a piece of kit in service.  Ideally one MiFi box could serve a number of cameras. This would reduce the camera power drain and consolidate.

The trouble is that the site is on the edge of town, a couple of hundred metres from the nearest houses, and I want to use BT Wi-Fi

I acquired one of these from ebay I didn’t have much hope for the integrity of the device, and to gain height I needed to go 250m further way from any likely source of WiFi. But it worked a treat, as a WISP client, I’m amazed. I was able to see 18 access points, five of which were BT WiFi , 3 of which were 5dB or above. The TP-Link gives a decent link at more than 5 and nothing at 2. I streamed a video to confirm the stability of the link.

I use it with a TP-Link TL-WA5110G which has the advantage of having a sma antenna socket and a native power supply of 12V. Although the adaptor is specced at 1A I measured the power drain at about 210 mA (~2.5W @12V). Which isn’t great but not terrible

A WISP client is not a  repeater

The trouble with using the tP link as a WISP client is the signal is presented as Ethernet, and I’d then want to re-radiate the signal on a different Wi-Fi network.  I could set it as a repeater, but then every Raspberry Pi would have the hurt of logging into BT WiFi. Whereas if I use a Raspberry Pi connected via ethernet to the TP-link and a WiPi dongle to connect to the farm I can collect pictures from the cameras on the farm network and perhaps power-manage the TP Link to only update every so often.

So an unexpected win, and I can look at using a Model B as a concentrator