Eggplants became too big in tight space now (stretching their shoulders 🙂 ). The middle plant below started to look stressed out by the side plants. So, it was time to move the middle one out of this area.
Now, this one has more space to grow horizontally and vertically. The leaves showed a little disease. So, I did a little bit of leaf cut.
Made Japanese “tsukemono” out of eggplants and cucumbers.
Made a video of the backyard garden for the first time as a story.
Just out of curiosity, measured the resistance of eggplants and tomato plants. When it is between the edge of a egg plant leaf and stem, the resistance value is about 2MOhm.
Old leaf doesn’t have moisture and it looks like the equivalent resistance of the old leaf is very high (i.e. open circuit). Small and young leaf have less resistance. Depending on the nutrition of the plant, the resistance seems to change.
I can use the tomato as a current limiting resistor to turn on a LED.
Tomato started growing more as the temperature in Oregon started going up.
There are six eggplants and each plant now has a bunch of flowers. At the same time, they attract snails 😛
Green onions. Bought green onions at a grocery store and kept them in a glass of water. Changed water every morning for two weeks and each has enough roots now. So, it was time to plant them outside.
SmartGarden device now is equipped with GPS sensor (Amazon Link) to keep track of real time information – GPS coordinates can be recorded as well. As the device has an USB charger block to power the Arduino microcontroller (Amazon Link) and other sensors, this became a portable device to check out brightness from the light sensor (Amazon Link).
The picture below shows the Analog Three-way meter and my own SmartGarden device.
Previously, the smart gardening device was built as an alternative method to the analog three-way meter (amazon link) shown in the picture below.
Using Arduino Software on Windows OS.
The arduino module used in this project is Arduino Micro (Amazon Link).
The data of light sensor output to Arduino are voltage values. In general, when it is brighter, the resistance value of the light sensor becomes smaller. As an example, about 100 Ohm in the sun light and ~ 10M Ohm in darkness.
Arduino microcontroller is programmed so that the log from Arduino produces the voltage value at a node of the light sensor every second. This indicates the brightness captured by the sensor. The data will be shown on the Arduino console and 4-line LCD.
With LED Desk Lamp, Arduino and Light Sensor (Amazon Link).
LED Desk Lamp has 4 light brightness levels
As the desk lamp gets brighter, the voltage value goes down. This means that the resistance of the light sensor goes down.
Test this prototype outside and compare the results with the analog meter.
Powered on prototype board successfully from USB power. LCD display was powered on at 5V. The light sensor has LED indicators showing power GOOD. Using a multimeter, measured 5V power pins on the prototype board and everything is okay so far.
Arduino micro has operating voltage at 5V. I like this because most LCD displays need 5V not 3.3V. Te DC current per IO pin is 20mA at 5V and 50mA at 3.3V, which is adequate for most sensors. Reference: https://store.arduino.cc/usa/arduino-micro
Today, I just powered on the prototype board ver 1 by a microUSB cable connected to a Desktop PC. The multimeter showed 4.96V on one of the sensor power supply pin. This is because there is a on-board voltage regulator on Arduino micro board and the 5V pin may not be exactly 5V due to dropout voltage. If the dropout voltage was too big, this may cause the Arudino and other sensors unstable. So far, it doesn’t seem to be a problem.