It looks as though yields of over 10 times what we can currently grow per acre are feasible if you control the CO2 concentration, the humidity, the temperature, all the various factors that plants depend on to grow rapidly.
Ralph Merkle
Finally with some time (thanks holidays!), the
Green House Project has bubbled to the surface again. Firstly we are planting peas and pumpkins in it's embracing warmth, but also it is appropriate to revisit the online monitoring with some new equipment that has arrived recently(-ish).
The old monitoring station used a crude time-stamp provided by literally turning on and off an
ESP8266 using an
Attiny85 as an alarm clock. The ESP8266 would power up and then log into the internet, hit a googlesheets page, and upload temp and humidity data gleaned from a
DHT11.
There were some issues:
- The DHT11 was slow to stabilise (around 2-5 seconds)
- Sometimes the Attiny85 would shut down the ESP8266 before connection or data transfer!
- Power usage wasn't ideal, with two devices and a sensor gobbling up more power than we would like
- Some other nerdy stuff like the nightmare of reprogramming the ESP8266
Since then, a couple of
BME280 devices have arrived, which don't need the long stabilisation time and can also measure atmospheric pressure (useful for the remote prediction of storms). Of course, they are more expensive, but
not prohibitively so.
We've also grabbed the more easily programmable
NodeMCU version of the ESP8266, which is just plug and program, rather than the confounding rat's nest of cables and separate power supplies previously needed for ongoing development. Also, we can now reprogram the device "over the air"
OTA, which is way cool - look ma no wires.
Finally, we can put the device into
deep sleep mode, which means no separate μC is needed to provide the wake up call, and therefore the device doesn't sleep until it has finished it's programmed functions (i.e. the data is transferred) which is highly efficient. We've also been toying with
alternative power management, so hopefully there will be increased power efficiency.
Next on the list is to swap away from the ESP8266 altogether, and use the newer
ESP32 (which some really nice features including bluetooth), a few of which have found themselves in southern Tasmania. But before learn run, learn walk.
So the fully experimental prototype of the new system is cranking out the air pressure, temperature and humidity
from our en suite bathroom for your viewing pleasure. It looks like this...
 |
| Dodgy looking, but functional! |
Stay tuned for more developments as the weeks unfold and the growing season swings into insane mode...
