from now on we will discuss on IOT (internet of things) and application for universal access design.
why IOT?
IOT help a lot in everyday life for whom hard to access to normal reachable like switch, dimmer, on-off for most electronic appliances, doors and vehicles. most IOT need bluetooth or wifi to access the control functions of devices. WIFI is more range and easier to deploy (other alternative is infrared but only line of sight is the limit for the solutions)
how to check the coverage of wifi that good for IOT?
best level of wifi coverage is –75dbi (what this number meant?)
how to check the level of wifi coverage at -75dbi?
the best and easiest way is walk to the place the you plan on put the IOT devices and use your mobile phone to check both stability and signal strength. stand at point around 3-5 minutes to see how signal swings
in case your wifi coverage was bad, how to fix it?
add more AP (access point) may help to fix this, before add more AP you need to learn how to select your AP and how it work
AP (access point) cheapest type of wifi expander you need LAN cable and power cable to connect to this and some has POE (power on Ethernet) that make use only LAN cable to provide both LAN and power connection. most AP has only 1 RJ45 connection
Wireless router more expensive but very versatile, you can set this as normal AP or use it as Wifi repeater. in most wifi router or wireless router has 5 RJ45 connection; 4 for LAN and 1 for WAN (separated network)
Wifi repeater lookalike wifi router or Power line adapter: repeat the wifi signal to other areas mostly drop 40% or more of original signal strength.
Power line Adapter use Power line (220 V or 110 V) to carried on signal mostly has 1 RJ45 connection and very compact size. some has wifi AP built-in. need at least 2 to work. do not use more than 5 in same area.
in detail we need coverage and easy to manage the wifi; each shape of AP tell roughly how the coverage be
each shape has different amount of antenna may change some detail of coverage but mostly follow the basics foundation
green is areas of coverage. orange is polarize of antenna(s) black is antenna or antenna covers