I'd like to create an alarm system to detect break-in in my garage graffiti on the outside. Below is a scetch of how this would look. The sensors have to be placed inside a garage made of concrete, and I imagine I have to run a cable to an outside antenna since I don't get wifi in the garage (and poor phone reception). The line of sight from outside the garage door to my balcony is 20m.
I was planning around wifi, using an ESP32 as an access point on the balcony or inside near the balcony door. This ESP32 would be connected separately to my wifi router.
Since there are some privacy issues with installing a camera there (it's a shared garage), I'm thinking I could ditch the camera and rely on just receiving trigger alerts from the sensors. Is wifi still the best choice for relaying triggers to the balcony? I have some external antennas for ESP8266, but they are only about 20cm long. Is it possible to extend this up to a meter with a coax cable?
The maximum distance between the various sensors are about 3m. This may be an issue for serial communication. I have therefore considered using NRF24l01 between the different modules. Is that a good idea, or necessary at all?
Could I also use NRF24l01 for the garage-to-balcony transfer? What about RFM69, is that better with regard to interference? The wifi band is quite crowded here.
Sorry, lots of questions here. I'd appreciate any and all input
WiFi is 2.4GHz which is essentially close to the home-microwave oven; therefore the ESP signals are microwaves and bounce and are easily absorbed by wood, concrent, and mostly anything with moisture content. Steel is especially nasty as it creates shadows in the RF path.
I would recommend backing down in frequency and using the lowest frequecy product that will be authorized in your region. Look into 433MHz or whatever you can find approved.
LoRa (Long-Range) is digital wireless data communication IoT technology. LoRa transmits over license-free megahertz radio frequency bands: 169 MHz, 433 MHz (Asia), 868 MHz (Europe) and 915 MHz (North America) . LoRa enables very-long-range wireless data transmission.
Image transfer is a nice option to have. I'll have to talk to the neighbors about that though.
I ordered a couple of Adafruit RFM95W 868 tranceivers.
Could I place the tranceiver inside the garage, and run a meter of coax for the antenna? Or will the signal would bounce up to the balcony so I can keep the antenna inside the garage? The building across from the garage is about 40m away.
if I need 2 of something I'll be tinkering with, I always buy some more just because it's soooo frustrating to wait for a replacement (esp. when you buy from the Far East) when you've done something bad and let the magic smoke out of the component
Just to let you know, lora works great. I left a transmitter on my desk and walked out to the garage. I received packets in thebuilding, in the garage, and for about 1-2 blocks beyond that in heavy rain.
Cool, yeah I'll look into the settings. One idea here is that I can extend the remote operation of my garage door, from something like 40m with the current remote to several blocks. I often get stuck at the intersection near my house where the remote won't reach. When I get a green light, I get close enough to open the garage door but then I have to wait 10 seconds outside while the door is opening. Got to add some encryption of course.
There's a lot of fluff on lora when googling lorawan and gateways. Crypto mining and whatnot. I'm prettty sure I don't need an expensive gateway if I just have a couple of remotes and a sensor node.
Oh, and I'm in Europe so I guess 868 is the only legal route..
