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IoT Hardware
rjp:
The RFM69 gear is much lower power than the esp wifi and with the right antennas can transmit large distances - the downside is the messages must be small, typically 50 bytes or less.
The reason you would choose it is if it needs to run on a battery or small solar panel for a long time in places without access to wired power.
An RPI gateway will have more features than an esp8266 gateway and can run the MQTT daemon (mosquitto) locally and run databases locally - so on small setups it can be the gateway and the server - the ESP gateway will still need a mosquitto server and database to send to.
As i recall the RFM69 stuff doesnt handle multiplexing, you need to build that logic into your system yourself - simple time allocations or error retries with random pauses are common solutions.
csheldon:
Ok, so in what situations would you choose Rpi for MQTT broker, and in what situations would you choose ESP? Is there any downside of ESPBroker having to send data to server in order to perform MQTT functionality in comparison with RPi?
rjp:
Id never use an rpi for an installation that was serious - Id only use it for hacks and around the house, i may change that opinion with the new rpi3 network boot but the SD card thing turns them into toys, not reliable machines.
ESP cant do mqtt broking, it can only do gateway - it will listen on the RFM69 network for new data and then forward it to another machine as an MQTT client, not server.
if you want a stable long lasting setup then you would use a server (ARM or x86) with hard drives or emmc instead of an SD card and then use gateway devices like the ESP to forward the data.
most of the ESP stuff is very cheap on fragile breakouts, id probably not use that in a serious application either.
csheldon:
Ok, let's see if I got things right:
1) RF to MQTT gateway (e.g. atmel + rfm69) is used if there is a need for low power nodes which can run on small batteries and consume small ammounts of energy.
2) Raspberry Pi is used as a MQTT device which can both run it locally (as a server) or be used as a gateway? It is not recommended though to use RPi in serious applciation, rather the best solution is to design embedded system with emmc onboard
-2 Questions here...If above is true..why do we then need boards like RFM2Pi which connect to RPi?, Also Why do we even need additional embedded system to run MQTT server locally if it can be set up on a remote server?
3) ESP onboard with RFM69 is used to gather data from RF to MQTT gateways (small sensors nodes, see 1. bullet) and then to publish that data to Raspberry Pi with onboard RFM2Pi, using the sam RFM69 on it's own board?
rjp:
--- Quote from: csheldon on September 22, 2018, 12:19:17 pm ---
-2 Questions here...If above is true..why do we then need boards like RFM2Pi which connect to RPi?, Also Why do we even need additional embedded system to run MQTT server locally if it can be set up on a remote server?
--- End quote ---
you dont *need* an rpi or an embedded at all.
rpi is just a linux server, it could be a huge x86 machine, it could be another type of embedded board, it doesnt matter.
rpi is trendy and well supported, so one of the feature it has is pluggable hats that do things like provide LoRa gateways - you can also buy those as standalone boxes that work with regular machines.
--- Quote from: csheldon on September 22, 2018, 12:19:17 pm ---3) ESP onboard with RFM69 is used to gather data from RF to MQTT gateways (small sensors nodes, see 1. bullet) and then to publish that data to Raspberry Pi with onboard RFM2Pi, using the sam RFM69 on it's own board?
--- End quote ---
you would not need both the esp and the rpi RF gateway - you only need one of them, the gateway just joins the RF network and the WIFI network
i would not bother with the esp gateway if i was running the rpi one.
i would not bother setting up the rpi gateway if i already had a server on my wifi network and i used the esp to gateway the RF packets to it.
both the esp and the rpi do WIFI/TCP so only one of them needs to also do RFM69.
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