Bluetooth or WiFi

[Speedy Builder5Participant @speedybuilder5]

I muck about with the Arduino micro controllers for various projects for my sins.  I am now using bluetooth and the DSD Tech Bluetooth software for the Iphone so that I can look at the readings remotely. Currently using a DSD Tech HC-05 but disappointed with the range – about 10 mt.

I also have a WiFi card ESP8266WiFi and Arduino Manager on the iPhone (which is set up for an Arduino R4 with WiFi, not the ESP8266 card).  Arduino Manager seems to be the answer but at first glance seems very complicated.

The router is in a house with 1mt thick stone walls and dg windows, one of my projects is in the garden about 14mt from the router, although there is a WiFi extender only a couple of mt from the project (Weather station with real time clock, memory card and temperature sensors).

My question is Which would give me a better range ?

Bob

 

[Speedy Builder5Participant @speedybuilder5]

forgot to add the photo

[John HaineParticipant @johnhaine32865]

Generally speaking you would get longer range with WiFi as many BT devices operate at quite low Tx power (though the maximum permitted is 100mW) being designed for “personal area networks”.  Neither of those modules look like they have very effective antennas, if you could find a WiFi modules that has an actual socket (they do exist) and fit a better antenna it would give better range.  I know of some work that was done evaluating a range of commercial WiFi routers from a number of manufacturers and basically the antennas designed in were c**p.  I doubt that the WiFi antenna in your phone is that good but using a better antenna at one end of the link will help a lot.

[SillyOldDufferModerator @sillyoldduffer]

Bluetooth is explicitly designed to be short range.  Low-power and an inefficient onboard antenna reduces the risk of neighbours and family interfering with each other.   Intended to replace headphone and keyboard cables, so normally less than 10m, obstacles permitting. BLE perhaps twice as far – I posted some figures recently in another topic.  Max range about 0.5km if both transmitter and receiver have good antenna in the clear, after that the packets time-out. BT won’t decode packets that take too long in transit.

WiFi is better – perhaps 100m outside,  but very dependent on the environment.   Not good at penetrating thick stone walls or steel-framed buildings.  WiFi eeceivers and transmitters can be had with coax sockets for an external antenna (beam on a mast), and transmitters powerful enough to wifi a large building or a camp site.

Short range WiFi devices like ESP microcontrollers normally link to an existing home network, so worth looking at plugging a better antenna into the router and/or adding a WiFi extender.   Position the router for range too:  top floor locations are usually better than cellars!

BT and WiFi are both are vulnerable to crowded bands and local radio interference.  A device will go further on an electrically quiet farm than it does in a crowded block of flats.

Dave

[Robert Atkinson 2Participant @robertatkinson2]

One thing I often wondered about these ESP modules with Wi-Fi is are they secure? How dow you know that they are not providing a back door into your network?
Then of course the minor issue that they are not approved so should not be used but that’s another story.

Robert.

[HuubParticipant @huub]

I use Bluetooth and WiFi to connect my CNC controllers but my shop i small. Beside those external boards I also use a lot of ESP32, ESP32-C3 and ESP32-S3 modules. The last 2 have a build in JTAG interface to debug code using the USB connection. The ESP32-C3 is my preferred choice for most boards I make.

In my home, WiFi has a range of about 25 meters through some walls and floors. The 2.4 MHz channel has a longer reach than the 5 MHz channel but the latter is not so crowded. I had a lot of problems when the boards where connected at the 2.4 Mhz channel and the computers at the 5 MHz channel. I tried 4 different brands of router but nothing worked reliable. Now I use a 2.4 MHz only Linksys router and the routing problems are gone.

[mike barrett 1Participant @mikebarrett1]

for long range and low power you should look at the LORA radio modules, easily capable of 1km range with the right aerials. It was designed for low power remote systems.

I have been using it to get data from a Arduino based Post Box topper back to my house…..

[Robert Atkinson 2]

On Robert Atkinson 2 Said:

One thing I often wondered about these ESP modules with Wi-Fi is are they secure? How dow you know that they are not providing a back door into your network?
Then of course the minor issue that they are not approved so should not be used but that’s another story.

Robert.

Well, security is multi-faceted.  Breaking it down:

• the radio-link is standard.  Security does not depend on the Physical and data-link layers, other than denial of service.  ESP no different from any other WiFi device.
• the network layer is encrypted, or should be.  An ESP cannot connect to a WiFi capable router without authenticating, which it does using the usual standard methods, which are no different from any other WiFi device.   Modern routers come pre-configured with strong security, old ones are downright dodgy, many defaulting to authentication not required or an encryption algorithm that was later found badly flawed.  Security depends on the owner setting old routers up correctly, often not done. Important to fix this because the router secures the entire home network.  Note the router is insecure, not the ESP.
• The network stack provided by Expressif is standard TCP/IP, supporting most modern security extensions as required.  However, older ESP modules may not be up-to-date.  Though the later ESP32 fully supports HTTPS in a straightforward way, the ESP8266 is harder to program, so HTTP might be used cos it’s easy.  Arguably, HTTPS isn’t needed on a home network because the network is already secure;  the router blocks external wireless connections and the internet.   But take care if the router’s firewall is opened up to allow outsiders to dial in!
• Much depends on what the ESP is used for:
  • Usually connected as a client to a server such as a 3d-print manager, control system, or data logger.  The server is responsible for security; it should insist that all clients obey the rules.  A home project might relax this requirement, relying on the router to block intruders.  Not unreasonable, but best-practice is to nail the server down.  It’s the server that’s vulnerable, not the ESP
  • Often programmed as a server typically running a miniature website.   The server is protected in the usual way by the encrypted home network, which an intruder would have to join in order to connect to the ESP.   Standard stuff, and pretty safe,  but best practice is that the website and server should implement strong security.  Again, arguably not necessary inside a home network.
  • Can be programmed as a server doing almost anything the programmer wants.  Web, email, file-transfer, whatever, with access via Bluetooth, I2C, serial, CAN, SPI, or IO pins.   The ESP can be a network Access Point, a Firewall, Router (connected to the Internet), Proxy, or Gateway to another network.  All these are a high security risk on any device.  Security depends on advanced design and programmer skills.  Not difficult to write a working router if you don’t care about security, much much harder to protect it.  As far as can tell the ESP platform is as secure as anything else, but it could be programmed badly or to do evil.  Man-in-the-middle attacks etc.

Dave

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