Author Archives: Dan K.

A method for observing the soil Nitrogen cycle in action

Background I had been developing a coir based organic plant growth medium for a couple of years and was getting fairly good results. However I wanted to know exactly what the actual nutrient levels in the mix were so I had a sample tested by a professional soil testing lab. The test was fairly expensive […]

Mesuring Changes in Soil Nitrogen

This post describes the method I have been using to follow changes in soil nitrogen using only simple equipment and inexpensive test strips. It evolved from earlier experiments involving an attempt to stimulate nitrification in an organic plant growth medium. See the post “A method for observing the soil Nitrogen cycle in action” for more […]

Insights from building an MQTT based User Interface

Note: Nov. 27, 2015, this is a quick first draft. I will be adding more details over the next few days including code snippets. Here are some insights gained from building an actual MQTT based UI. Using a system consisting of a Raspberry Pi 2 with Raspbian Jessie installed on an 8GB class 10 SD […]

Building a browser based User Interface with MQTT

This post is focused on use with a Raspberry Pi but should also apply to most Linux systems. It all started when I was trying to find a way to have Python code in the SIP irrigation control software  project update an image on a page of the program’s web UI. When I tried goggling […]

Installing Mosquitto MQTT broker on Raspberry Pi (with websockets)

This post describes the steps I used to set up the Mosquitto MQTT broker (server) with websockets enabled on a Raspberry Pi . This can provide two-way communication between Python programs and JavaScript. For example: A python program can send a message and have JavaScript update part of a web page in a way that […]

Setting up a Raspberry Pi to work with OpenSprinkler (Old post)

NOTE: This is a very old post and is only kept here for historical reasons. More recently I have been working on a Python port of the OpenSprinkler software which was originally written in C for an Ardino based sprinkler controller. The new software supports a simple plugin architecture for adding custom features. There is […]

A Homemade Atmometer

An atmometer is an instrument that measures evaporation and simulates transpiration by plants. It is an aid to irrigation scheduling and can also be useful for studying microclimates. It simulates plant transpiration by drawing water from a reservoir by capillary action then allowing the water to evaporate from a surface that is exposed to the […]

Drip Irrigation for Home gardens–Getting into the zone

There is a lot of information on the net about drip irrigation systems. Many of the sites with detailed instructions seem to be focused on farm type setups.  I want to share the development of a system for my small home garden. The information that follows is for the benefit of home gardeners, especially for […]