After mixing different source of information, I was able to decode some Oregon Scientific sensors to get Temperature and Humidity indication, over the air, on 433.92MHz, with a Raspberry PI system. This article gives some details of this adventure …
You follow this implementation at your own risk…
If you are interrested in this article, you could also take a look here where you can find a RF433 shield and the associated code
After having test some receiver, naturally, I’ve tested some transmitters, the objective is the same : get the best coverage in the same condition : I would say poor conditions. Lots of wires going every where and an antenna make with a simple 17.3cm wire. As expected, results vary regarding the emitter used. Reed more to get details.
I’ve just done some test on different RF433 receivers, from the classical really low cost system to some more expensive systems. The test environment was always the same : a dirty test board with lots of wire connections everywhere and an antenna made with a 17.3 cm wire. The conditions are poor but identical.
Then I move around my house and activate my alarm detector one after one and check if the system received it. Some detector are same floor, 1 floor or 2 floors distance, some are behind walls, distance vary from 5 to 20 meters in house.
The following results are the number of message received by the different receivers in this context. More you see, better it is.
I start using mosquitto in a C++ program and I think documentation could be a little bit improved by some examples. To use mosquitto, there is a mosquittopp class acting as a wrapper on top of the mosquitto lib. Basically to create your own program you have to herit from that one and it is easy then.
Mosquitto lib can be managed as a thread or directly by calling the different sub function. In my point of view the thread approach is the better as otherwize you have to manage connection / disconnection manually. Mosquitto lib is then event managed, so you can subscribe to the callback event by surcharging the existing function.
Here is an exemple for a program just needing to publish messages to a broker.
An easy way to create a word list in bash :
for i in {a..z} ; do echo $i ; done
for i in {a..z}{{a..z},{0..9},-} ; do echo $i ; done
for i in {a..z}{{a..z},{0..9},-}{{a..z},{0..9},-} ; do echo $i ; done
The first line creates a list of one characters word from a to z
The second line creates a list of two characters word from aa to z- the alphabet for the second character can be a-z or 0-9 or –
The third line is a three character word list.
Ncrack is a new brute force tool made by nmap, it’s actually a alpha version but the product is really interesting to verify your password policies compliance and security. It support ftp, telnet, ssh, rdp … protocols.
Easy to use in command line, I only tested it with rdp, unfortunately with no success even knowing the password to be found. I assume it’s just an alpha bug. In my point of view the multi protocol implementation makes it an interesting tool for audit automation.
I’m interested by MQTT for two reason, the first one is related to its services and QoS management, the second by its network efficiency because I’d like to use it over a 3G communication system with a small and low cost plan.
MQTT promise is to be network efficient but, i’d like to see it with my eyes, so I’ll try to give you some measures I’ve done to confirm it. My fear is that keep alive communication for subscriber costs could be high and request some software adaptations.
See full article to get details and eventually reproduce
MQTT (MQ Telemetry Transport) is a Message Queuing system for machine to machine communications. It allows communication of mobile systems over high latency, low bandwidth and poor quality networks. It manage communications over TCP (not over Http) to optimize the size of messages and it manages different quality of services. Depending of it, messages can be dropped, received multiple times of you can have the insurance to receive the message one and only one time.
It makes this protocol really interesting for the communication between a raspberry PI and a server when this communication is event driven and the communication link looks like a Edge/3G channel.
Mosquitto is an open source implementation for MQTT.
Here are some tips on how I implemented it, for a demonstration purpose