Web dashboard for IKEA Krydda

Firmware sketch for ESP8266 with web dashboard on adafruit.io

Dashboard for my growth system

To monitor your cultivation unit from local/ everywhere I wrote a sketch to both send the actual light intensity values via the serial port and to adafruit.io which is a nice web service for displaying data in the internet (of things).

Currently only the light value is displayed and more sensors will be added in the future.

You can see the actual values of my Krydda system here.
 
More information on how to set up your own dashboard on adafruit.io can be found here

UPDATE 23-5-2016: Added temperature and humidity with the Sensirion SHT21 sensor.

IKEA hydroponics - First sensor for ambient light

Sensor measures light intensity for the plants

Lights sensor BH1750FVI connected to a ESP8266

The first sensor for my IKEA hydroponics project is a ambient light sensor (BH1750FVI) which will measure the light intensity on the plant bed in both the seed and cultivation unit. It is currently connected to an ESP8266 - a DIY-friendly and hacker-famous microcontroller with WiFi on board. I wrote a library for the light sensor which works with both Arduinos and ESP8266. You can find it here.

Germinated seeds in cultivation unit

The example sketch in the repository currently measures only the actual value of the ambient light. In future versions this sensor will be responsible deciding if and how long the IKEA LEDs have to be switched on depending on the overall light which fell on the plants. There will also be an uplink to a web-service (like Thingspeak or adafruit.io) where all the values are monitored in real time on a nice looking dashboard and will be accessible from everywhere.

In the meantime the seeds that germinated changed their habitat to the cultivation unit.

 

Power supply for remote sensors

Presentation: How to supply power to microcontrollers/ (remote) sensors with low dropout (LDO) voltage regulators and batteries

"Classic" 7805 Voltage regulator

On August 5 I had a short presentation at the Makerspace Attraktor in Hamburg on how to supply independent power to devices like standalone microcontrollers or (remote) sensors.

 The talk gave some comparison about different low dropout voltage regulators which are by design very well suited for battery powered devices. Decision finding on what parts are most suited and design considerations for independent sensors were explained detailing a remote temperature sensor project I'm working on for about two years now.

XBee temperature sensor

You can find the presentation (in english) here

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Temperature sensor current consumption

1 year with batteries - temperature sensor project

Temperature sensor with alkaline batteries

Just a quick update on my XBee/ LCD/ temperature sensor project which I originally started in 2011 (last blog entry: XBee temperature sensor project ). I  had to replace the already used battery cells which I put into the sensor about one year ago (August 31 2012) because I got some timeouts on my receiver. The
voltage came down to 3.34 volts and this is a point where the low dropout regulator (MCP1700) keeps quit working sometimes even when the load is only about 25 mA every four minutes when the XBee (end device, sleeping) sends the temperature data to the coordinator.

Voltage development temperature sensor

The three battery cells had a voltage of around 4.1 volts when I started using them for the sensor, so they were already down from their original voltage/ capacity which is around 1.5 volts per cell for unused batteries.
Why did I use used battery cells and not new ones? Because they were lying around and I was wondering how long some spare, already used cells would last during time and different weather conditions. And they lasted almost one year!

The temperature sensor is located outside and we had temperatures of around -15 to +30°C during the year. The chart you see is far from scientificly accurate but gives you a raw picture of the voltage curve for those cells (GP super alkaline).

Next I will replace the batteries with some rechargeable batteries. There are some nice energy harvester ICs on the market - maybe this will be the next power supply for my sensors. Stay tuned.