Figure 1 : Sensor node
The original purpose of these nodes was to add an IoT (Link) element to the networking module i.e. a distributed sensor network. The aim here was bring in some "embedded" networking protoctols such as Message Queuing Telemetry Transport (MQTT) (Link) and Constrained Application Protocol (CoAP) (Link). However, plans changed :), never enough time to cover everthing. Therefore, these nodes are used in the lab as broadcast packet sources i.e. every 60 seconds they broadcast sensor data.
In the past i have made simular Pi based sensor nodes and from that experience i found that the heat of the Pi does have a significant impact on sensor readings, sooo for this implementation i decided to mount the sensors well away from the Pi. The height above the Pi was determined by the length of acrylic rod i had to hand, approximately 100mm :). The sensors used all use the I2C interface (Link) so you only need space in the tube for 4 wires: +5V, 0V, SCL and SDA. The different 3D printed and laser cut components are shown in figures 2 - 5 and can be downloaded using the links below:
Figure 2 : DXF files, pi base (top), sensor top, sensor bottom (bottom)
Figure 3 : STL files, base block (top), sensor block, sensor sides, pi cover (bottom)
The electronic sensor modules
Driver / interface code
COAP
directory structure
storing data
MQTT
Python code network
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Figure 2 : computer science departments around the world.
WORK IN PROGRESS
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Contact email: mike@simplecpudesign.com