The full GSM thermostat is managed by a Microchip PIC18F46K20-I/PT microcontroller, programmed with a firmware that controls the temperature and takes care of the communication with the GSM module which is the component named GSM; this is, in fact the small board hosting the cell, so the pins’ numbers refer to the used pin-strips’ contacts….
Excellent to remotely control via GSM the activation of engines, lightening or watering systems and alarm systems. It sends commands through SMS as well as with DTMF dual tones and allows you to check if they were successful. In this post we present the last application created from the development of the modular remote control…
For the GSM temperature controller we have provided a double-sided PCB with plated holes, made by photoengraving; once you have the board you can start the assembly with SMD components.
The thermal probe can also be mounted out of the PCB, connecting it somewhere else by means of a three-conductor cable, at least 20 meters long.
Let’s now look into the schematic diagram; in it you can note the usual Microchip microcontroller governing the GSM/GPRS module activity, controlling the logical condition of the two opto-isolated inputs and managing the two relays. Moreover, the PIC interacts with the DTMF decoder in order to recognize the dual tones used for the phone selection…
On the construction perspective, the remote control does not present many difficulties, just the obvious ones that appear when working with circuits requiring superficial assembly components. As usual, there is a PCB with double plating where to mount all components.
The set of commands of this remote is divided into two categories: the SMS ones and the DTMF tones. The former are simply summarized in the corresponding table, since they are the same as the ones described for remote 2 IN/2 OUT. Here we will only describe in detail the DTMF commands, first stating that…
Commands can be given in two different ways: the first one is to send the SMS according to required syntax and with the password (if required), needful to avoid strangers to operate the configuration; the second one is to introduce, through Easy Setup, the number of the mobile enabled to make the following settings via…
Up to 200 numbers can be stored and enabled to control the relay, which allows people to use the gate opener not only in big condos and residences, but also in companies and all those other contexts in which many users are likely to need to have access. In order to avoid using SMSs, which…
Commands and settings can be sent by any cell phone via SMSs, as long as the message in question contains a password. Some of the commands can be composed without the use of a password (just so that they can be composed faster), provided that they are sent from one of the first eight numbers…
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