Hello fellas!

It's been a while since my last update, but a lot of things have happened in the background. The machine has now been re-organised so to speak. The components have all been fixed in place, and I have added a couple of new sensors: CO2 and O2.

The sensor in the centre of the image is the K30 from CO2Meter.com. The other sensor in red, is the O2 sensor from DF.Robot.com

The internal components are now fixed in a two levels 'chamber' below the enclosure for plants.

I ran out of space though, so I had to relocate some of my arduinos (I have 4 arduinos in total) to the back of the box. As I am still missing the CO2 injection control and feeding systems, it's very likely that some relays and timing will require another extra arduinos. This is how the back of the box looks like now:

Finally, I need to seal tightly the plant enclosure, so I can measure oxygen and carbon dioxide without external interferences. I also need to keep carbon dioxide at pre-determined levels to study carbon fixation through rapid light curves and what not. The box is also getting some acrylic panels for aesthetic reasons. I have not finished that yet, but you can see a snippet in the following picture:

I still have to do some work with the CO2 generator, which is a simple system I bought from Amazon.co.uk for £20 quid (Coca Cola bottles, nitric acid and baking soda). I am planning to use a couple of manual valves to feed CO2 and purge the box when needed; or, and that is just if I feel like doing it, I will install a couple of solenoid valves along with a relay to control the gases. The thing is, the latter option is a bit expensive and it may not be required. I also have to feed the plant with a drip form of irrigation, as I cannot open the enclosure during experiments. 

Finally, there is that big lingering question of temperature and humidity control. In theory, I should install some temperature/humidity control mechanism so I can play with those variables too. I am also concerned about the lack of air circulation so, I may settle for an external system with vents etc. But first things first, I will finish the final adjustments (enclosure and gases control) so I can run some experiments during the last part of winter (January and February) and see how the data looks like. A big part of this machine is also software related; I want to start playing with some form of machine learning, so the box can, in a not too distant future, control the variables on the go to reach certain performance levels. All in all, it seems I will be working on this box for the foreseeable next year too!

Oh! and before I forget, I haven't managed to sort out the F0 issue (see my previous update for a background on it). Long story short, I need to figure out how to blast the plant with 3 pulses that are no longer than 300 milliseconds in duration, and all this within one second. It turns out that I can't do that with an Arduino. I haven't put too much effort on this, but I will, eventually.