Panic Button DIY
It so happened that one grandmother for over 90 years remains at our home for a long time - my wife and I work, adult children live separately and, of course, also work. It happens that grandmother feels so unimportant that getting up, answering the phone and calling her is very difficult. A cell phone may also be useless, it requires some attention and relatively precise actions with its hands. Neither one nor the other if you feel unwell may not be enough. It should also be borne in mind that you can not get through the first time, that a cell phone may not be at hand, that it may have a battery, etc.
In this regard, I attended to finding a solution for the immediate alarm signal in the most accessible way for an elderly person with the maximum possible coverage of the alert. The scenario is as follows: the grandmother presses the buttons noticeable to her, located in the most likely places of her presence and a call and an SMS from the “Panic Button” subscriber comes to the cell phones of all the relatives involved in the script. Everything should be as simple and reliable as possible and require a minimum of maintenance. On the Internet, you can find devices and even tariffs for such solutions, but, frankly, the prices are such that they discourage any desire to use them. So it would be nice to optimize costs.
And then, what can be compared with the joy of independent creativity in the field of electronics! So, spitting on my hands and a soldering iron, I got down to business! The result was this solution:
')
For the material part, Master Keith modules were taken.
As buttons, we will select MP910 key chains operating at a frequency of 433 MHz - I took 3 pieces.
For these transmitters, you need an appropriate receiver. Since only one channel is needed to react to pressing the button, let's use the MP911 - a 433 MHz receiver for the remote control operating in the “button” mode.
And to send messages and calls using the module MA3401 - Autonomous GSM-SMS alarm system . This module is still good because it has a memory for 6 numbers, it can report power loss in the house and the temperature in it, and also has some other useful functions that we will not use yet, but remember for the future!
Having bought all these devices, I rummaged in the stocks and found the suitable case.
Since the GSM module is powered by a lithium-ion battery that charges from 5V supplied to it via a mini-USB connector, I decided to use the MP911 receiver module (it is powered by 12V) to remake a bit to power it from 5V. To do this, it is enough to replace the 12 volt relay installed on it with a 5 volt relay and feed 5V from the MA3401 directly to the receiver decoder chip.
A normally closed (so that there was no interference) connect the relay contacts of the receiver with the input of the Button MA3401. Then, when the relay contacts open, an event will occur that the GSM module reacts to.
The following photo shows how to apply 5V power to a receiver with a decoder.
To accommodate the modules in the case, as well as to replace the regular buttons in the key chains with more noticeable red and rough ones, I used the DIY's best friend - a 3D printer. I have a printer designer from Master Kit MC2 with its own modifications. I wrote about them in materials 1 and 2 . Drew and printed small stands for the body, and buttons. Got both pleasure and practical use!
Here is the device turned out when everything gathered:
The remote control on the next photo in the center was specially left unchanged, as it was, so that the difference could be seen.
Grandmother was strictly ordered one button to be hung on the neck and not removed, the other two were glued on a double-sided tape in the apartment.
Check the performance of the system:
Adding a decision from the author on issues in the comments:
1. The unit is powered by a USB connector on the computer (thin client with low power consumption), which is always on and itself, in turn, is connected to the UPS. The unit has a lithium-ion battery, which is charged when an external power supply is connected. This process is indicated by a flashing LED. In the device itself, you can turn on the SMS notification mode about the loss of external power.
2. No problems with noise immunity. Between the remote control and the receiver is a poll "friend or foe". The receiver should not react to third-party signals. But, if it accidentally works, an extra bell will hurt. The system of the alarm button is not the only way to monitor - there is video surveillance with a motion sensor, for which the Hikvision DS-2CD2412F-IW camera is used.
In this regard, I attended to finding a solution for the immediate alarm signal in the most accessible way for an elderly person with the maximum possible coverage of the alert. The scenario is as follows: the grandmother presses the buttons noticeable to her, located in the most likely places of her presence and a call and an SMS from the “Panic Button” subscriber comes to the cell phones of all the relatives involved in the script. Everything should be as simple and reliable as possible and require a minimum of maintenance. On the Internet, you can find devices and even tariffs for such solutions, but, frankly, the prices are such that they discourage any desire to use them. So it would be nice to optimize costs.
And then, what can be compared with the joy of independent creativity in the field of electronics! So, spitting on my hands and a soldering iron, I got down to business! The result was this solution:
')
For the material part, Master Keith modules were taken.
As buttons, we will select MP910 key chains operating at a frequency of 433 MHz - I took 3 pieces.
For these transmitters, you need an appropriate receiver. Since only one channel is needed to react to pressing the button, let's use the MP911 - a 433 MHz receiver for the remote control operating in the “button” mode.
And to send messages and calls using the module MA3401 - Autonomous GSM-SMS alarm system . This module is still good because it has a memory for 6 numbers, it can report power loss in the house and the temperature in it, and also has some other useful functions that we will not use yet, but remember for the future!
Having bought all these devices, I rummaged in the stocks and found the suitable case.
Since the GSM module is powered by a lithium-ion battery that charges from 5V supplied to it via a mini-USB connector, I decided to use the MP911 receiver module (it is powered by 12V) to remake a bit to power it from 5V. To do this, it is enough to replace the 12 volt relay installed on it with a 5 volt relay and feed 5V from the MA3401 directly to the receiver decoder chip.
A normally closed (so that there was no interference) connect the relay contacts of the receiver with the input of the Button MA3401. Then, when the relay contacts open, an event will occur that the GSM module reacts to.
The following photo shows how to apply 5V power to a receiver with a decoder.
To accommodate the modules in the case, as well as to replace the regular buttons in the key chains with more noticeable red and rough ones, I used the DIY's best friend - a 3D printer. I have a printer designer from Master Kit MC2 with its own modifications. I wrote about them in materials 1 and 2 . Drew and printed small stands for the body, and buttons. Got both pleasure and practical use!
Here is the device turned out when everything gathered:
The remote control on the next photo in the center was specially left unchanged, as it was, so that the difference could be seen.
Grandmother was strictly ordered one button to be hung on the neck and not removed, the other two were glued on a double-sided tape in the apartment.
Check the performance of the system:
Adding a decision from the author on issues in the comments:
1. The unit is powered by a USB connector on the computer (thin client with low power consumption), which is always on and itself, in turn, is connected to the UPS. The unit has a lithium-ion battery, which is charged when an external power supply is connected. This process is indicated by a flashing LED. In the device itself, you can turn on the SMS notification mode about the loss of external power.
2. No problems with noise immunity. Between the remote control and the receiver is a poll "friend or foe". The receiver should not react to third-party signals. But, if it accidentally works, an extra bell will hurt. The system of the alarm button is not the only way to monitor - there is video surveillance with a motion sensor, for which the Hikvision DS-2CD2412F-IW camera is used.
Source: https://habr.com/ru/post/371981/
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