Leon Burkamshaw
I am always needing to log and measure something, perhaps this is the engineer in me. I initially liked the idea of something that has on-board logging but there are times when i want to log the data and check on it periodically without having to retrieve the data logging device, hence the need for something wireless and the reason for my project.
The wireless node has a digital temperature sensor built in which covers many logging requirements (this would have to be the most logged variable ever?) There are also pins available to add external analog and digital sensors.
I am currently setting this device up to monitor my mains gas usage. The logger is configured so that external pulse or count type sensors connect to the internal microcontroller counter and therefore allow the micro to be in sleep mode while still counting, this allows for a long battery life. The battery voltage of the node is also measured and sent along with any logged data.
The idea behind the device is that it wakes from sleep at a programmable interval, measures its sensors and sends the data, then goes back to sleep. Using this method batteries can last a long time but provision will also be added for basic solar trickle charging to greatly extend life.
At the receiving end another nRF module is connected to a Raspberry Pi. The received data is pulled from the nRF module FIFO , time stamped, then appended to a CSV file. For now this is a rather simple way of storing data but plans for the future are to upload the data to a cloud based service that can plot the data.
The system diagram above provides an overview of the parts that make up the wireless logger and an idea of where i am upto. The basic setup is complete and i have sample data being sent and captured by the Raspberry Pi. Next step is to do some more thorough testing and then add multiple nodes.
Alex
IoTool
Sylwester
Natty Bumppo