![]() However, it is more convenient if you open the 'Instructions.docx' document and copy and paste the commands from the document into the terminal window. Next, we do some updates by typing certain commands in the terminal window. However, once we reboot the system we have to type sudo –i once again. With the root privileges we don’t have to type sudo any more at the beginning of each command in the terminal window. Before we move on we give the user root privileges for the whole session with the command sudo –i The shortcut for this is on the Desktop (WiFi Config). Raspbian Wheezy offers a WiFi configuration utility. If you are using an USB WiFi dongle set up your WiFi connection. You will end up in the configuration menu to do some settings such as choosing the language, local time, keyboard layout, etc. Insert the SD-card into the Raspberry Pi and start up. Windows users can do that easily with the Win32DiskImager. When starting from scratch, download the Raspbian Wheezy operating system from the Raspberry Pi Foundation and transfer it onto the SD-card. Check the correct position first! The wires can be soldered to the top end of the required GPIO pins and passed through holes on the Adafruit PCB (printed circuit board), see fig. The stripboard is glued to the LCD plate with a hot melt glue gun (fig. It fits nicely on the backside of the LCD plate without causing problems placing the LCD plate onto the GPIO pins of the RasRi. Using a stripboard allows you to assemble tightly the few parts of electronics (resistors and wires) as a kind of prototyping circuit board. If they are of same kind the script has to be adjusted for either GPIO pin 11 or 12 depending of the type of sensor. If two sensors are used in total (yes, that is also possible) it is more convenient if they are of different kind. That gives more flexibility in using any water sensor unit and the corresponding GPIO pin can be selected in the script and hence indirectly the kind of sensor. However, the meaning of high and low is here vice versa, i.e. Alternatively, a sensor can be connected to GPIO 18 (pin 12) accordingly. When water is detected, the relay closes and pulls GPIO 17 from 3.3 V (high) down to GND. 3 allows reading high or low on GRIO 17 (pin 11) according to the status of the water sensor. The water sensor has to be connected to the GPIO pins. 2 Resistors (1 kΩ and 10 kΩ) per sensor unit, stripboard, wires.12V power supply for water sensor unit (e.g.1 or 2 water sensor units, for example from Pollin.Enclosure which suits the LCD Display, eg.Adafruit RGB Positive 16x2 LCD+Keypad Kit for Raspberry Pi or Adafruit monochrome Positive 16x2 LCD+Keypad Kit for Raspberry Pi.Internet connection either via LAN cable or USB WiFi dongle.The following hardware is required for this project: The video shows the RasPi in operation with many of its features. That might be helpful for any kind of maintenance on the hardware. ![]() The email-addresses and phone numbers will be listed allowing comfortably checking whether they are still up to date.īy pushing any of the buttons on the display board a query for shutting down or rebooting the system is prompted. On the first day of every third month an email is sent to the first email-recipient reminding that the RasPi is still alive despite the activated built-in hardware watchdog. In contrast is the arrangement in figure 2 with a monochrome display and everything kept tidy in a waterproof enclosure. That emphasises the beauty and production quality of the RasPi but also allows a good access to the buttons on the LCD display. The arrangement in figure 1 houses the RasPi with the LCD display in a Perspex enclosure, and the power supplies and the water sensor unit (without the probes) are protected in a waterproof box. Alternatively, a corresponding monochrome display can be used as well, see figure 2. The setup uses the Adafruit RGB Positive 16x2 LCD+Keypad Kit for Raspberry Pi allowing a red or green backlight indicating visually the status of the water sensor(s), see fig. That allows comfortably updating remotely the data on the RasPi via SSH without affecting the running system. The data will be read in by the main python script on demand. The phone and email list is kept in a separate simple txt-file. If the running system hangs up for some reason, an activated built-in watchdog would automatically start up the system again running the required scripts for the water alarm system. When water is detected the Raspberry Pi emails out an alert to a recipient group and calls a phone number list via VoIP playing a stored wave file with a spoken alert phrase. The Raspberry Pi reads the status of one or two water sensor device(s) on one or two of its GPIO pins. ![]() Instructions for employing a Raspberry PI as a water alarm system
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