November 2019 – Medway Makers

Mike has decided to upgrade his InfluxDb and Grafana server from the Pi 3B+ to a new Pi 4 with 4Gb of RAM. To speed things up even further, he purchased an M2 NVMe SSD card to boot the OS from and make the speedy Pi 4 even faster.

The SSD is a WD Blue SN500 M2 NVMe SSD which has a 250Gb capacity. The drive is contained inside a USB 3 enclosure. The Pi 4 was flashed with a brand new copy of Raspbian Buster and then the latest versions of InfluxDb and Grafana were installed

Mike used the instructions from on the ‘Toms Hardware’ website which can be found HERE.

The Pi 4 with the SSD is now considerably faster than the old Pi 3. Grafana dashboards load faster and in particular, choosing data ranges in Grafana displays the data noticeably quicker than previously. The extra 3Gb’s of Ram should also ensure that the Pi does not start grinding to a halt as the database gets larger.

To keep the Pi 4 cool it is being moved soon to a new Pimoroni PiBo case with the fan shim. This will then be stuck to the back of a monitor in portrait format to display the Grafana dashboards.

4Gb Pi 4 with 250Gb SSD in a USB 3.0 enclosure

If you want a much faster Pi with plenty of storage space, an external M2 SSD is recommended with a Pi 4.

ESP8266 temperature & humidity sensor node

Mike has recently been adding some more sensors to his sensor network around the house. To add to the Weather Station sensors that are out in the garden, plus the Environmental Monitoring Station sensors and CO2 sensor node, a BME280 temperature and humidity sensor node has been added to the network.

Data from this sensor node is being transmitted back to Mike’s InfluxDB database on a Raspberry Pi. The new sensor node is currently in the bathroom with similar nodes being added in future and dotted around the house.

This particular sensor node is in a ‘dead bug’ style with all of the components soldered directly to each other, rather than using a breadboard or PCB. For such a simple circuit this is ideal and makes the whole thing compact.

Voltage divider resistor to monitor battery voltage

A 220K ohm resistor was soldered between the 5v input pin and analog pin A0 to allow for the battery voltage to be monitored. The node takes temperature, humidity and voltage readings every 20 minutes, transmits this to the InfluxDB database and then goes to sleep.

All of the data, once stored on the Raspberry Pi is displayed sing Grafana’s beautiful dashboard graphs and gauges as below.

The code for this project can be found on Mike’s Github HERE.

Month: November 2019

Upgrading to a Pi 4 with SSD

ESP8266 Sensor Node