Plants update

So we started the first seedling 2 months ago now, and I had to add some more in the meantime, but here are what we have now:

• Basil (from seeds),
• Thai Basil (from cloning),
• Tomatoes (2 from seeds, 1 from clone),
• Red Lettuce (seeds),
• Bok Choi (seeds),
• another Chinese cabbage (seeds),
• Strawberries (seeds),
• Winter Squash (seeds).

Basil is really easy. As you need to prune it regularly, keep the heads in water for a few days, and will make some roots. You can plant them to grow new plant.

I got 2 tomato plants: the leaves curled and got flaky... then died. The other two were nice ! 

The squash is amazing ! It drinks a lot of water, but still so funny to see it growing.

Strawberries are the slowest... of the seeds that came out, because Coriander never sprouted !

Lettuces are quite weak, and they tend to die with the wind. I'll try other species.

First test with Moteino's & Raspberry Pi running TheThingBox

So we're getting close the the architecture we'll be running. It is based on Moteino nodes (Arduino compatible with RFM69W) talking to a gateway based on a Raspberry Pi running TheThingBox (Raspbian, Node.js, Node-red, Mosquito).

First I used LowPowerLab codes for the nodes and the gateway Moteino. There are two moteino loaded with node firmware transmitting text strings over encrypted radio (915MHz) to a gateway Moteino. The gateway is plugged thru USB to the Raspberry Pi.

TheThingBox is quite easy to operate: download, install on the SD card, plug it, and turn on. Voilà ! A simple sketch is loaded in the sheet: serial input to debug.

And on the right side, you can see the text string sent by the Moteino node is now displayed on the debug window on the right side.
The only tricky part is to get the right serial port of the Moteino connected to your Raspberry Pi.

1. Log on your Pi thru SSH
2. Type ls /dev/tty*
3. Plug your Moteino USB or Moteino with FTDI adapter
4. Type ls /dev/tty*
5. Compare the two results, you should have a new TTYUSBx listed

This is the value you'll put in the serial config of the sketch.

Moteino are in the house !

So after researching online which node I would use for the sensors/actuators network, I first had a look at the Jeenodes as they are quite popular and cheap. The main issue today is that they are using a RFM12B radio module from HopeRF, and this part number have been phased out last year. The replacement unit is the RFM69W, which is not yet supported by Jeenodes. So far, the best developments made around the RFM69W/HW and Arduino comes from Felix Rusu of LowPowerLab: the Moteino.

As it was designed to be a wireless node, the RFM69W is directly soldered on the Moteino pcb and there are different options for antennas (no antenna, 1/4 wavelength wire, SMA connectors, etc.)
There is no FTDI chip on it to save space and also costs.

For the gateway, you need a Moteino USB as this one has to be permanently powered, the USB connectivity & power feed is a better solution.

I also took a Power Shield as it drives & charge a LiPo battery and provide juice for the node. Once assembled with a cheap HK$45 LiPo pack from Sham Shui Po, it looks nice !

Now the tests. Once the library installed, there is an exemple for the node, and one for the gateway. The gateway still plugged to the computer, and you open the Serial monitor inside Arduino IDE, and the strings start to be transmitted.

The range is more than what is needed, but it will help to have a wireless connection between the sensors (pH, Water Temperature, Air Temperature, Humidity, Light, EC, etc), the actuators (pH up, pH down, Nutrients A, Nutrients B, Water), and the controller (Raspberry Pi with IoT software).

Installing the perilstatic pumps

I've bought 5 perilstatic pumps on Taobao from Kamoer (KPP-S06-DG-C0). They are quite cheap and the only drawback is, like all perilstatic pumps, the tube has to be changed every 6 months or so. You better order some silicon tubing at the same time.

The big clear IKEA Trofast container that was helping algae to develop will now be used as the solutions storage. An additional small Trofast will get the pumps.

I've drilled 5 holes (30mm diameter) in zig-zag (4 cm far from each center, the two lines are 2cm far from each other).
5 holes will be drilled for the silicon tubes to reach the bottles stored underneath. And one more for the wiring. I'll put the electronic board with the TIP120 transistors and the Arduino in that level too. You'll need another hole to reach the motor poles.
I've selected 12V pumps because I'll have the solar panels feeding a 12V battery system, so it's much simpler that way.











The system can add pH+, pH-, nutrients A, nutrients B solutions to the circuit. One water jar will be added to the system to flush or add water to the circuit.
The flow of each pump need to be calibrated as it depends on the section of the silicon tube. So for the water jar, you better have a bigger section (-S10).

Maybe I'll add the batteries for the solar panels in that tank too.