I am attempting to grow the best pepper plants I can indoors (grow box) so I started with jalapeno peppers. They grow relatively small 2-3 feet and require 2-3 gallon container for growing. While this is fine for an outdoor garden, though indoors I can only sacrifice 1 gallon container. This summer I grew several jalapeno plants which spent half of their life in the grow box and spent our warm summer outdoors. All of the plants produced but there was definitely a clear winner which had incredible early yields even with its small growing quarters.
I used several immature peppers (green) for salsa this year but allowed several peppers to mature (red) which I will be saving the seeds for planting this winter and next summer for future plants. By hand selecting the best parent plants should be good old natural selection at work.
The process to collect pepper seeds is pretty simple though I must first provide this warning:
WARNING: Peppers are hot, especially the veins. When handling peppers use caution and wash your hands well with dish soap. Under no conditions do not rub your eyes or pick rub your nose before washing your hands or you will be regretting it for a couple hours. Using gloves is also recommended.
That being said slice the peppers lengthwise with a sharp knife.
Use a fork or spoon to gently dislodge the seeds into a small bowl.
If you are lucky enough to have hot sunny weather still (week of rain here) lay they out in the sun for a couple days and store them in a cool dry place until you are ready to plant them. If you are sun challenged like me set them on a windowsill for a few days.
As I have said before saving you own seeds is very easy and free and as an added bonus you can personally pick the best plant to be the donors of seeds for your future plantings. In my case I also have the benefit of a plants that is genetically grown to following my sporadic watering and care patterns.
While my existing system was working I decided to make an upgrade to the electronics on my old grow box controller specifically to have a much more industrial strength version that will run without problems for decades to come. This version also is much safer…still probably not quite to a building code but much less worries to burning my garage down in the middle of the night. Finally it is modular if there are problems in the future I can easily switch out electronics or sensors.
Well now I have attempted to justify my reasons this is what I used to put the whole thing together:
- Enclosure big enough to fit four Solid State Relays (SSR)
- Breadboard or custom PCB
- soldering iron and solder (optional if using breadboard)
- 4 – solid state relays
- 4 — 1K resistor
- 4 — 2N2222 transistor
- 4 — 1N4004 diode
- DS18S20 (1Wire temperature sensor)
- 4.7K resistor
- 10K resistor and homemade soil sensor
- 18 gauge triple stranded solid copper wire (5 feet)
- Industrial grade sockets (1 male/4 female)
- Old Ethernet cable
If we had lawyers, they probably would want us to say this:
WARNING: I am not an electrician and do not pretend to be one. I do not know the specific building electrical codes of your area, so please be sure your wiring is completed under the proper safety code for your area. As always, using high voltage electricity can result in self-electrocution or burn down your house if not done safely so if you are not comfortable doing this wiring please contact a qualified professional.
Putting it all together
On the electronics side overall the circuits are actually pretty simple and if using a breadboard definitely something that could be tackled by a beginner. Though on the other side since this project is dealing with AC current I definitely would recommend caution (no hands unless power is unplugged) or have someone a little more comfortable with 120/220V help you out.
I will be the first to admit that using an Arduino for this application is complete overkill for this application but it gives plenty of room for additions in the future. For all intents and purpose you could have your grow box completely controlled from the Arduino own processing power though on my case the software and UI is more interesting part to me. For this reason the Arduino code is actually very “dumb” basically just taking commands via the build in serial through USB and setting digital outputs to HIGH/LOW or reading analog inputs.
Here is the code for your grow box controller:
Copy and paste the above code into your Arduino software. For the code above I used the OneHire.h library which is free to use and can be downloaded from here. To be able to use this library simply copy the contents to C:\arduino\hardware\libraries\OneWire. Now you should be able to Compile (CTRL+R) and upload the code to the board (CTRL+U)
Now with the software uploaded you can send some simple serial commands via its built in USB to serial adapter to interact with it. The interface is are broken up into 1 to 4 character commands, which I will detail below
|T||Returns temperature from One Wire component|
|D4H||Sets digital pin 4 to HIGH (ON) (replace 4 for alternate pin)|
|D4L||Sets digital pin 4 to LOW (OFF) (replace 4 for alternate pin)|
|A1||Reads analog value from pin 1 (replace 1 for alternate pin)|
|PING||Returns PONG which is used to confirmed controller is online|
|V||Returns version which is some forethought into the PC application being able to support different versions of controller software|
Using the build in serial monitor tool in Arduino.exe, my application, or you should be able to control your Arduino with this very simple command based interface
Now you can hook up some LEDs and watch them blink which is fun for a little while but if you want to add some grow box components read on….
As you can see I have fully embraced the circuit schema on the back of a napkin idea. These are the actual diagrams I crumpled up and stuffed in my pocket with several trips to the garage for some final soldering of various joints until everything was solid.
Below is the simple circuit required to get your 1Wire temperature sensor working. I would recommend checking your documentation (if not labels on the chip) for the orientation to have 1 and 3 correct, if you have it wrong you should get some complete unrealistic number. Hook ground up to pin1 on the DS18S20 and pin 2 hooked up to the digital input pin 8 on the Arduino with 5V with a 4.7K resister in between to step down the voltage.
If everything is hooked up correctly you should get the current room temperature in Celsius by sending command “T” to your Arduino. If you prefer Fahrenheit uncomment line 162 and recompile and upload your changes, though if using my software I support both degree types and do the conversion in the the software. To make sure everything working (or just to play with your new toy) put your fingers on the chip for a couple seconds and take another measurement unless you keep your house very warm the temperature should go up a couple of degrees
Turning things on and off (Relays)
If you were smart enough to check the current requirements of your Solid State Relays (SSR) before you bought them you may be able to skip this whole circuit and simply hook the digital outputs to the 5V positive side and ground to the negative side of the SSR.
Unfortunately if you are like me and bought some SSRs that require more current draw than the Arduino (or any other IC chip) of 40mA then you will need to create the simple circuit below.
Basic idea is pretty simple, you are using the output from the digital pins to switch of the transistor which then allows the ground to complete the circuit with the thus turning on the relay. As you can see there is a 1K resistor between the base (middle pin) of the transistor. If you are not using a SSR relay (though recommend you do) you should add a 1N4004 diode between the positive/negative which protects the transistor from being damaged in case of a high voltage spike which can occur for a fraction of a second when the transistor switched off, this is also known as a back-EMF diode or fly back diode.
Now here you have a couple options. If you are confident of our wiring skills you can do like I did and take a couple of sockets and hook up the neutral and ground in parallel. Two save space and since I really didn’t need two separate plug-ins (nor its own plug) for each relay I removed the little metal bar between the two sockets so they could be switched on independently. Now simply hook up hot to the left side of all your relays in parallel and then connect a wire from the right side of the relay to its own plug on the two sockets.
Now a less wiring intensive method is to simply take a 6 foot (small if you can find them) and cut the hot wire (usually the one with non-smooth wire) and attach each end of the wire to both sides of the relay.
When it comes to a moisture sensor there are a few options. First is the classic two galvanized nails, second is the cheap gypsum soil moisture sensor which I have written up in the provided link.
If you are using the other options you will need the simple circuit below. Technically it is a voltage divider, but that doesn’t really matter. Just hook up one end of your sensor to 5V and other sensor to ground with 10K resistor and also connected to analog pin 0.
My custom PCB solution
I actually started the work to create my own PCB at least a few years back. Played with if it off and on and finally pulled the trigger to get some boards printed up which I must say was very rewarding and pretty fun experience for just $20-30 of out of pocket cost. This provides all the circuits I mention above with a bonus circuit to let me know when my water reservoir is running low. I also installed a Ethernet socket not
I designed this to be an Ardunio which plugs directly on top of the Arduino. In theory I could stack more functionality on top of if but haven’t though of anything cool to do here yet.
Don’t want to spend 10-20 hours creating your own PCB and then wait 2-3 weeks for it to arrive from Hong Kong? Well you can do the same thing with a bread board which I show below.
Virtual breadboard layout
If you are new to soldering or have no interest in learning I would definitely recommend this option. Simply place the components in the holes and make connections with 18 gauge solid copper wire. You should be able to pick a small breadboard for less than $7.
Of course for my application, I am using this to integrate with my custom software solution to control my grow box. Specifically soil sensor, temperature measurement, heater, lights, exhaust fan, and water pump. So using the circuit mentioned above I ran the hot wire through each SSR with the remaining wires connected to the plug and eventually gets plugged into the wall. Then simply hooked up the wire from the Ethernet cables to the low voltage side to turn the switches on/off. So I would say this is a bit of an improvement over my last attempt…
Last I hooked the arduino up to my PC and used my custom software to control the temperature, water, and provide cool graphs as you can see below.
Sometimes life can get busy and you have limited time to keep an eye on your plants, for these times I also integrated with a custom Windows Phone 8 application which allows me to check the current state of the grow box using life tiles, water remotely (turn on/off lights/heater/fan as well), or even check out a current feed inside the grow box.
Looks at the actual actual grow box…
I have almost everything planted at least germinating in my grow box. As you may be able to see from the labels I am growing a variety of peppers this year as well as a few different onions and tomatoes. I also have garlic and some onions I overwintered already outside and peas already in the ground.
I did successfully grow some peppers in the grow box over the winter, though as you can see below their size was lacking and the plant has been perking up a bit with some new growth once I added some better controlled heating and the LED lights.
Always running out of room in my grow box I needed to expand it some. Though the CFL lights I was using worked great for my 3 square foot space, though by nearly tripling the square footage CFLs wouldn’t scale out anymore. Looking at my other options such as HPS (High Pressure Sodium) or Metal Halide I really didn’t want to deal with ballasts and cooling I decided on going with LEDs. After doing some research I came upon the 120w Extreme Flower LED grow light and after talking to the great people at Advanced LED Lights they were gracious enough send me with one of their lights to try out.
Now as soon as I opened the box I noticed the sticker that said "Do not look directly at light.” Being a moron I just had to plug it in and test out this warning, now it was not like staring at the sun but it was definitely much brighter than my Christmas grow light and I would not recommend others to do this.
The light offers a unique blend of 11+ wavelengths of color ranging from 380nm to 760nm and if you read my post of the importance of wavelength to plant growth this is critical for vegetative and flowing plant growth. The great thing about growing with LEDs if you can pick the specific wavelength produced for maximum yields, though other lights also provide this spectrum they also produce much in the range that is appealing to our eyes (yellow and green) which the plants could live without. This is the reason why this 120 watt grow light can produce the results of a comparable 250w High Pressure Sodium light.
I still have some work to do on my new bigger grow box before I can move this years plants in, but I am excited to see the results this new light will bring. Stay tuned for more updates.
How many times have you been riding the bus and have been curious what temperature your computer growbox was running and if the plants needed to be watered? Ok maybe never, but I decided to solve this problem anyway. There is also no point in identifying that you may have a problem without having a way to do something about so I also implemented the ability to override the controls on the growbox by using a Windows Phone 7 application on your new T-Mobile cell phone or any other cool Windows phone.
I made the design for this pretty simple, unfortunately I could not connect with my growbox directly using a mobile device because the computer is behind a firewall (which is a good thing) so I used machine that both the mobile phone and growbox can contact cheapvegetablegardener.com. After creating a quick web service with the following methods the growbox and mobile device could now talk to each other:
- SetStatus(StatusInfo) – GrowBox sets this status every minute
- SetOverride(OverrideInfo) – Mobile sets override to default functionality
- GetStatus() – Mobile Phone gets status
- GetOverride() – GrowBox checks for potential overrides requested by Mobile device
Now I have the two devices talking here is the basic UI. The top half of the screen shows the growbox temperature, cpu temperature, and the moisture content. All of these statues change color (to yellow and red) as their values get to critical levels (too hot, too cold, too dry)
The middle section shows the current state of the growbox letting me know if the lights, heater, exhaust fan, and/or water pump are on or off. If a situation occurs where you want to override this state you can do this by simply clicking the status indicator.
The bottom part of the screen shows temperature and moisture levels over the past 24 hours. The graphs are rendered using Google Charts for simplicity though am thinking about creating my own custom solution to get the graphs just right. It also displays a current screenshot inside the grow box and you can transition between views with a finger swipe.
|Temperature history graph||Moisture saturation history graph|
Overriding the heater setting
Status screen following heater override
Though this covers most of my required functionality, I still need to add some cool transition animations and some additional analytics, but thought I would share my current version.
I recently moved to a new office building and unfortunately I had a lacked a few years at the company to get a window office. With a desire to have some plant life in my office, I grabbed a couple of the basil plants I cloned, dropped them in some potting soil, and positioned a desk lamp with a CFL bulb. I can’t seem to find my lamp timer so the light has been staying on for 24 hours a day.
The results have been great, the plants are thriving with great green foliage (much greener than its cloned parent was outside this summer) Shortly after taking the picture above a harvested some of the leaves and used the top portion to clone into a new basil plant.