Second attempt

Hi all!
2 part question

PART1 - measurement
I am doing a plant watering project, and have already “failed” by starting with the wrong hardware. It turns out that I cannot use the RS21 module with the Hydra board that I ordered, so in order to avoid further mistakes, please advise me if I am on the wrong track:

  1. I have a moisture sensor
  2. I’ll have to order a premium mainboard, such as the spider? (why aren’t these boards clearly marked?)
  3. I’ll be purchasing the RS21 with the intention of:
    3.1 obtaining a IP settings from my wireless router
    3.2 using http to execute a POST command via the WebClient class in System.Net namespace (i.e.:

PLEASE let me know if the plan I have is possible using a spider and RS21, I’ve already wasted money on the Hydra following advice from ghi employees whom did not understand what I want to do.

PART2 - acting
For part 2 of this project, I was thinking of adding a pair of ZigBee’s to the same mainboarfd (spyder?) in order to control two valves FROM the cloud, the process goes something like this:

  1. The Spyder polls a webservice endpoint whenever it has connectivity, no more than once every 15 minutes
  2. If a watering instruction is found by polling, then the spyder will, via the zigbee’s, activate a different mainboard (my hydra maybe) to first open up one valve to let water inside a dispenser. AFter a few seconds, the first valve closes and the second valve opens, which releases the water in the dispenser to the plant.

I need help with:

  1. Part number / how to obtain two valves that can open/close like this
  2. Something I can verify amount of remaining water with
  3. Check if there is anything else I need to realize this.

The project that I am aims to be as overengineered as humanly possible, that is why I am using cloud services (Azure) as part of the solution. I will also write mobile phone apps for statistics and simple - I realize that I could’ve done this a whole lot easier,however that is not the point :slight_smile:

In advance, thanks for reading and for all your comments and suggestions

This page pretty clearly spells out the premium versus open-source hardware platforms

Part 1. If you are expecting to use an RS21 you need a Spider (based on EMX module), a Cobra2 (based on G120 module), or a G120 or G400 “HDR” module.

An alternative is to look at a different wifi module (say the WiFly) that might meet your needs - I have no direct experience with other technologies to answer whether these are going to suit all your needs - and continue to use your Hydra. So I would say that the problem isn’t that you have a Hydra, it’s more that you haven’t understood what options you have here and resolved how you’ll approach the problem. (I personally think your comment about GHI giving you advice seems misguided)

3.1 is all about DHCP. Most routers provide this, most wireless modules support this, but there are combinations that don’t work together (there is no magic formula here that I know - you must test it to know it works).

Part 2 - is totally a problem outside the usual realm of a specific microcontroller, and becomes more a watering automation problem. You should approach this differently and probably go to a different forum to find options here. Whether you can use a zigbee to trigger this directly will require you to have resolved what option you are going to control - and if not you may need a mainboard interpreting/acting on that control. One other thing you can almost guarantee is that there’s unlikely to be a circuit board explicitly designed for this so you’ll possibly need to make some custom circuits here (veroboard/stripboard may work, but it’ll still require some tinkering).

Thanks for the detailed reply, Brett.

If I understand wifly correctly, it is a bridge to using the zigbees which in turn are wireless serial ports. This would force me to have an internet-connected computer at home to do the actual web posting with. The database, and web service endpoints in my solution are cloud hosted, thus the need for my mainboard to be able to reach the web through the WebApi classes.

It is correct that I did not understand the options when I ordered the hydra, and I’ve probably not made it clear enough to ghi when asking about the devices and internet connectivity - which resulted in me ordering the wrong stuff

  • I do not blame anyone but myself for this, even thoguh I do believe that the component listing should have a clearer marking of what pieces that can communicate with eachother. There should, for example, be a very clear NOTE section on the hydra, explaining that this is a limited device that will not work with some of the modules in the store.

For part 2 - where should I look up valves?
It is my understanding that I need some generic module for the spider that I can use to output voltage to operate the valve with. Additionally, I’ll need the valves themselves - I need advice on both

But not sure how to control it from spider

@ digitaldias - I just started playing with the WiFI RN171 ( module, which is what I believe @ Brett is referring to. It is full blown wireless module which can be run as an Access Point or it can run in infrastructure mode and join your existing wireless network. Form a software perspective you see it as a UART device, but on the air is standard wireless 802.11b/g.

The module ships by default from GHI configured as an Access Point and that is what the driver supports so it requires some work currently to join an existing network, but I have my module configured to join my home network using WPA2 with no issues at all. I use Putty to telnet wirelessly to the device’s management interface and everything works very smoothly at least from my experience so far.

I am currently using it on the Cerberus, but I see no reason it will not work on the Hydra as the interface is simple UART. But If you like I will gladly test to be 100% sure since I have a Hydra handy.

Take a look at the data sheet and user manual for the device

The WiFly was what I mentioned and what I intended to talk about - as a “drop in” to an xbee adapter module. The RN171 is another different but possibly more expensive option, but I think the only supported method of using it is as an access point, not in infrastructure mode - if GHI support is important then it’s unlikely that it’ll do what you need in the short term.

As for valves and watering automation, you’ll have to look. is a good place to start :wink: You will find lots of people automating this, but your specific requirement (measured dosing of a volume of water via something that isn’t a “flow meter”) is not something you’ll get the right advice from here. Then once you get some guidance and options from that, you can figure out how you’ll need to interface it, don’t assume it’ll need relays, or that relays are the solution to a problem that can be solved with relays (for example, they draw current when actuated, is that a consideration?)

@ Brett - Sorry for the confusion, I thought you might be referring to the RN171 module because as I am sure you are aware the WiFly is actually based on a RN171. Other than connectivity options they are really the same thing.

Nope, wasn’t explicitly aware that the wifly was based on the RN171 - thanks! There’s my “one thing I learnt” for the day :slight_smile: :slight_smile: I could go back to bed now and be happy.