I’ve put the MEAN stack exploration on hold as I’ve been itching for many years to get into hydroponics. I wanted to see what could be done with LED strips in terms of lighting. The objective was to quickly slap something together to get see how the plants responded.
- 2 x NooElec 1m 60-Pixel Addressable 24-Bit RGB LED Strip, 5V
- 2x BTF-LIGHTING WS2812B 144 leds/pixels/m
- 1x DROK® DC-DC High Power Buck Voltage Regulator Board 5-40V to 1.2-36V
- 1x DS3231 AT24C32 IIC RTC
- 1x xbee S2C
- 1x Arduinio Mega
- 1x xbee explorer
- 1x LM35
- 2x 220 ohm resistors
- 1x 0.01 micro Farad capacitor
- 1x 1000 micro Farad capacity
- 1x soil moisture sensor (not required but I had it lying around for a while)
- 1x 12V power supply
On the Mega front, I had Chinese knock off and it was garbage. The voltage regulator fried, the TX1 via the header pin did not work, and the headers were loose. I bought the real one as troubleshooting on the knockoff is not worth the effort.
I also got tired of wiring xbees on breadboards so I finally purchased the wireless connectivity kit (S2C) and the pro version of the xbee so I could program some custom functionality in the xbee in the future. BTW, digikey Canadian or US site offer great service and fast delivery. I’ve ordered from them several times.
The following diagram illustrates how things were hooked up. The LM35 when used with other analog inputs leads to erratic readings so the capacitor used to stabilized things.
The software was straight forward and for now, I used the xbee in AT mode rather than API mode. The end result could user an xbee gateway (my mean stack) to push and receive information. For now, I just used modbus to communicate to Mango and for giggles VT-Scada. More on that in a future post as the IIoT speak I hear from certain vendors — not the two mentioned–make me cringe knowing what they have under the hood.
- set time from host via modbus or terminal console
- set lights on time via modbus or terminal console (default 18 hrs on)
- set lights off time via modbus or terminal console (default 6 hrs off)
- set duty cycle via modbus or terminal console
- set duty cycle period via via modbus or terminal console
- get temperature via via modbus or terminal console
- get soil moisture via via modbus or terminal console
- force the lights on or off via modbus or terminal console
- save/load/restores settings in EEPROM
Modbus was used as I already had a SCADA host running. It could have been xbee API or bluetooth. Having done both this is relatively easy to refactor into the code later.
The code can be found at https://github.com/chrapchp/PlantLEDLighting. Not the prettiest code but it does the job for this experiment.
The duty cycle is periodically changed between 70-95% red with the remaining in blue light. The research in this space for plant LED lighting is growing along with plenty of do-it-yourselfers experimenting.
Basil and oregano took a couple of weeks to germinate and growth has been slow at best. Basil likes warm and nitrogen rich earth. It could be that 68F is not warm enough. Who knows. I’ve never been successful growing the herbs.
The kale and arugula germinated in 3 days and grew relatively fast. The stems are weak and I’m thinking that the LED’s are not intense enough. I’ve planted some outside as well and will compare the stem sizes with the indoor ones.
There seems to be some confusion out there between lumens and pars. I read about people only measuring lumens for plants and scratch my head. I like ChilLED‘s pitch in positioning their lighting products as well an intro-101 from Lush Lighting.
I could try different soil, nutrients, and seeds yet I think what I have it terms of pars and power for lights is too low. There is also talk about the effects of UV as well. I’m told that more UV causes ‘certain’ plants to product more THC. I am not interested growing those plants and just want to grow edibles all year round.
I’m considering using at ChilLED for sourcing my lighting needs. I do want control the output of the various channels without using their controller. I would like to build my own and growmay5 provides some interesting vlogs on this as well as other topics around LED plant lighting.
Lastly, I’m satisfied with experiment and how quickly I could mash up a solution. Hydroponics is the next step with better LED lighting and queued for later this year as a project.