The sun appears to move in the sky. First let’s explore how the sun moves through the seasons. We will consider the sun’s position in the sky at midday (solar noon). The tropics are at a latitude of 23.4 deg. The northern tropic, the Tropic of Cancer, is at latitude 23.4 deg north and the… Continue reading How high in the sky is the sun?
Category: Technical
Markdown Syntax
Introduction There’s no definitive Markdown specification so to learn its syntax you have to hunt around a little. John Gruber devised the original Markdown syntax which he documented on his Daring Fireball site The Wikipedia article documents attempts to standardise markdown. These have been unsuccessful so de facto standards have emerged based on influential users… Continue reading Markdown Syntax
Checking the pulse from the meter light sensors
Introduction Following on from the last three blogs I thought it worthwhile checking the quality of the signal from the light sensors. Using an oscilloscope I measured the pulse at the Arduino pins. Results What surprised me was the quality of the pulse was good. I thought I would need a decoupling capacitor close to… Continue reading Checking the pulse from the meter light sensors
Arduino to monitor electricity usage
Introduction To monitor electricity consumption of a house I have proposed a light sensor to detect the flashing of the LED on the electricity meter that indicates energy is flowing. In previous blogs I have covered the selection of light sensor and its electrical connection to an Arduino Uno. Now it is time to look… Continue reading Arduino to monitor electricity usage
Connect light sensor (TSL251) to Arduino Uno
Introduction I wanted to monitor my electricity usage. The house has an electronic meter with a flashing LED so the task becomes one of detecting the flashes from the LED and counting them. The selection of sensor is explained in Sensors to detect LED output on electricity meters. Meter to Arduino The electricity meter and… Continue reading Connect light sensor (TSL251) to Arduino Uno
Sensors to detect LED output on electricity meters.
Many UK houses have electronic meters for measuring electricity consumption. Most of these have an LED that flashes when a given quantity of energy has been consumed. In the UK most meters have LED outputs which flash once for every 1Wh. They will flash 1000 times for each kilo-watt-hour (1 kWh). If a sensor is… Continue reading Sensors to detect LED output on electricity meters.
IOT Devices – to push or to pull?
Introduction There are two methods to collect data from an monitoring device. The device can be asked to provide the data or the device can be programmed to deliver the data without prompting. The situation is similar for control devices. Push or pull? When researching the devices connected to the Internet of Things (IOT) you… Continue reading IOT Devices – to push or to pull?
Nginx and uwsgi
Nginx is great for serving static pages and acting as a reverse-proxy. When a dynamic page is needed then a second process is used to generate the page. Introduction When setting up a web site it’s common to use nginx as the front-end. Nginx is great for serving static pages and acting as a reverse-proxy.… Continue reading Nginx and uwsgi