The timeline

After the mediocre performance of my vegetable garden last year (50% of the plants produced), winter is the perfect time to reflect on what went wrong. First, I started the project with a simple idea and absolutely zero experimentation. Second, the methods I chose did not work as I had hoped they would and my fall back was too simple. Third, minor tech troubles exacerbated the issues caused in the previous two steps. To address item one, I have started prepping my solution as of the end of November 2017 with an eye on March 2018. This is giving me time to test and refine as I go. On item two, I had to look at what worked and what didn't. The pump system worked well, but needs to be reconfigured to deliver water at the soil level; even a moderate drop of four inches resulted in erosion and root exposure over time. The planters were acceptable, but the height differential was tough to deal with. New planters will be needed. The right microcontroller was not available immedia...

I finally got my watering to work consistently. All it took was replacing the MOSFET with a switch relay and some persistence in getting the damn ESP8266 to connect to the network for more than 5 minutes. I also had my first crop: green beans (or as they seem to be called in the US, string beans). Still waiting on the tomatoes, but I fear the aphids may have undone the good work so far. So, here's the setup: Two window boxes featuring, from left to right, carrots, green/string beans, tomatoes, and strawberry. The white PVC pipe has drill holes to provide water with a length of flexible tubing entering it on the left, supplying the pipe, and the right end of the pipe emptying back into the reservoir. A design issue with this simple setup is that the pipe is too high - it can easily erode un-mulched soil. In a better-designed setup, I would have the reservoir lower than the return so that the pipe can sit on the soil. The reservoir: Nothing fancy here. A 12v DC pump su...

Nothing is as easy as it seems. A new attempt at making the watering system operate via a web interface hit a snag. I purchased, and soldered, a new NodeMCU unit. This unit has only 16 pins, as well as the expected ESP8266 chip, but unlike my other two units it also has a 5v pin. I was excited, hoping that, like an Arduino, the 5v would be available through the signal pins. No such luck. The 5v pin is the only pin with 5v logic; all other pins operate at 3.3v, which is insufficient for the N-channel MOSFET used to control the water pump. Anyway, a new attempt: using the new NodeMCU unit with a switch relay. The other NodeMCU units couldn't do this as they were entirely 3.3v; the relay requiring 5v to flip the switch, but only needing 3.3v for the signal telling it to do so. Whether my relay works with 12v logic is another matter - I bought it for mains electric control, so it's only ever worked with AC. Wish me luck.

So, I have been having issues with my automated watering system. I had built a moisture sensor from metal screws held in a plastic lid. Using nuts and washers I could hold wires in place rather than trying to solder on to such thick metal. To prevent surface water completing a circuit, I sealed the heads of the screws with waterproof caulk. However, after two weeks of good performance, the sensor went doolally and emptied the water source in one go. I had avoided the usual issue of electrolysis by powering the sensor circuit no more than four times an hour for a few seconds each time. The screws do not appear to be damaged, but readings are consistently showing high resistance, even in waterlogged soil. Rather than leave my plants at the mercy of the weather, or a malicious water sensor, I have decided to move to an ESP8266-driven setup. This setup uses and ESP8266 to trigger the arduino controlling the pump. Why two microcontrollers? The ESP8266 board only has 3.3v out, but has...

Well, here it is. Post one. This blog will probably veer wildly between subjects that interest me. I create automation using Arduinos, NodeMCU, and Raspberry Pi hardware. I write in Python, mainly, but I can write HTML, CSS, and Javascript as well. Beginning a tentative paddle in the shallow waters at the edge of C/C++, primarily as a consequence of Arduino. I also have an interest in practical applications of technology, with a focus on performing tasks that I do not have time to complete with a job and a family. My first such project involved building an automated watering system for a vegetable garden (not a unique project, but a fun one) and future work involved looking into automating an indoor hydroponics setup for herbs with an eye to possible production for local restaurants. Given the locality, basil, oregano, and other Mediterranean herbs seem to be the best candidates. Longer term, I'm looking to design a larger planting area, away from wifi, that communicates ...