In my vegetable garden (no WIFI) i've installed a sprinkler system, which i would like to control remotely from my house (12 km away). I had in mind to use a Arduino Mega in combination with SIM900 mini v3.8.3 module to send text messages from my phone and thereby changing settings of the sprinkler system (like the amount of water to distribute, which day of the week to turn on, which sector to water, which timepoint to water and many more)
This is what my sprinkler system looks like in action:
In the past years i've been using an Arduino Uno chip to circulate the water in my greenhouse and therefore i am aware that it will drain a relatively large amount of energy from my 12volt batteries that i have been using. Therefore this chip needs to be saving as much energy when it can and therefore i had in mind to only turn the GSM module on, once a day for a few minutes, to receive potential text messages and next run the normal scripts.
I did manage to setup the GSM module by connecting it to serial 1 and i am stably receiving and sending text messages when the GSM module is turned on and connected to the network. Generally the chip needs like 80 seconds to connect to the Vodafone network and generally i leave it on for another 4 minutes to retrieve whatever is available. Unfortunately i just found out that like 80% of the text messages that i send with my phone, when the GSM module is turned off, are never retrieved by the GSM module. When i insert the SIM into my iphone it does retrieve all text messages that have not been received in the past 2 days. So i am pretty confident that both the network is working properly. Also when the GSM module is turned on, i do receive 100% of the messages that i send in the timeslot of 4 minutes.
Any suggestions what i can do to make sure that the GSM module is receiving all floating text messages as well?
Battery that i am using: 12v 26Ah battery (of like 2 years old)
Going to solid state relays will help with battery life they pull much less current to operate. How long does the battery last now and how long did it last when new?
The idea of this system is that year-round it should function. If i take an Arduino Uno with sleep modes programmed and a relay that turns on a 12v pump 2 times 1 minute every hour the battery last around 1 week. I charge the battery at the same time with a 55W 12V solar panel. This works really well from april - sept when solar energy is abundant, that way, i never run out of power. But during the other months i need to be more careful preserving energy. Therefore my setup with sleep modes of the Arduino Mega.
I am pretty sure that if the GSM module would be on 12 or 24 hours a day it would drain my battery extremely fast, faster than i can charge back with the solar panels. Therefore i am committed to stick to the energy saving setting of only turning the GSM module on 5 minutes a day.
I did not explain all other more complex components but you can imagine that the sprinkler system itself is NOT running on the 12v 26Ah battery. Here i use a 140Ah 12v battery and a transformer which turns it into a max 2000W 220v current that is used by a 1700W rainpump. To water the vegetable garden this turns on approx 5x 1.5 minute to dispense like 1000 liters of water in that time.
In my plan the rainpump is on a independent network from the control system.
The control system uses for example motorised 12v valves to distribute the water in different sections (also minimally consuming power), to work hand in hand with the energy draining relais! Good tip of using solid state relais in the future, but luckily this is not the component that is draining a lot of energy!
My simple question: any tips to make sure that the GSM module will more actively retrieve textmessages circling in the Vodafone network? Could a longer Antenna or a higher Current supplied to the GSM module make a difference?
(I also have a Arduino Uno GSM/GPRS shield brand new lying around but haven't tested it and i am not sure whether this will make a difference for my issue?)
