SIM800L GSM Module and Arduino Nano: Automate Yard Hydration via SMS, Solenoid Valves, and Relays

Hello, I have a GSM SIM 800L module and I would like to use it to turn on the hydration in the yard. I also have an Arduino nano but I don't know how to do it. It would work like this: I send an SMS to 800L, and this one activates the solenoid valves via relays and after some time 5-15 minutes it disconnects the solenoid valves. Module photo:

Hello,

I am currently working with this module.
I will not implement the service of incoming text messages until the coming month.

Overall, the matter is quite simple:
- You connect to the module via UART with arduino with parameters 9600/8 / n / 1
- You communicate with the module using AT commands (you can find documentation on the Internet)
- The module is quite demanding in terms of power supply and how many GSM modules generate a lot of EMC / EMI / AUDIO interference around them. It requires a power supply in the range of 3.7-4.2V and an instantaneous current efficiency of 2A.

If you needed a printed circuit board to solder this system, the STM32 microcontroller would not hang on the wires, we will get along somehow. I have several laminates on sale ...

Below I present a partial diagram of my implementation and the source code as such ... I am programming the STM32L152RE microcontroller.

Ok thanks for your help, I have a logic level converter and I would like to know if it is needed here.

The module works for me without any problems with the 3V3 logic.

Added after 3 [minutes]:

czareqpl wrote:

Hello,


If you needed a printed circuit board to solder this system, the STM32 microcontroller would not hang on the wires, we will get along somehow.

Do you have etched tiles ready for sale?

Can you see what this tile looks like?

The tiles I use for this are fully professional.
4 layers, gold plating, double-sided solder mask and description. The dimension is 138x83mm I guess.

This is what an already assembled module looks like:




If necessary, I can also take a photo of the laminate itself, but this is a little later.

I don't know if I will be able to do anything about it without the code.

I can share the code. Same with the diagram and assembly drawing. There is an STM32L152RE microcontroller on the board or another STM32LXXX family can be soldered.

czasnagli wrote:

Do you have etched tiles ready for sale?

Yes, I still have 3 pieces of what is shown in the pictures and 1-3 pieces of an older generation PCB with minor errors in the audio track (which can be shown.)

Thanks for the info, but your board is too complex for me.

Cool. You don't have to use everything on it. Basically, for STM and GSM to work, you need a small LI-ion battery, one LMZ10501SILT inverter, TP4056 charger + protections and some capacitors.

Maybe I have an inverter somewhere on another album that I could translate.
What you can see in the pictures is a complex prototype that also includes a gyroscope, accelerometer, compass, bluetooth, raspberry pi, GPS and a GSM module. Each of these components is optional and the microcontroller will go without them.

I used this module in audio and SMS communication. It works very simply through AT commands. This means that when the SMS arrives, its content will be sent to the UART. Now you need any uP (or uP module) with UART that will read the SMS, turn on irrigation and turn it off after a certain time. I recommend to connect this module to the computer via UART and UART USB converter. You can then play with AT commands from the terminal, see what comes, how it behaves after the reset, etc. This knowledge will be very useful when creating a program on uP. Watch out for power! I put this module in the Chinese breadboard and it wouldn't work. It took a long time to realize that the contacts at close range had 2ohm of resistance!