Hi, this is Wayne again with a topic “Didn’t Wash Hands Alarm”.
This week we’re making an alarm that goes off whenever someone forgets to wash their hands in the restroom. Here’S how the overall system works. One sensor is attached to the pipes of the toilet and detects when the toilet is flushed. Two more sensors are attached to the pipes of the sink and detect when the sink is used. One last sensor is attached to the door and detects when someone opens the door to leave the restroom. All these sensors are monitored by an arduino microcontroller. If someone uses the toilet and leaves without washing their hands, it activates an alarm.
So the first step is making a sensor that can detect when water is moving through a pipe. I chose to use a piezo sensor. These sensors convert pressure and vibrations into a small electrical signal, start by removing the piezo element from the plastic housing and disconnect any attached circuitry to make it easier for the arduino to monitor the piezo element. I added small amplifiers to each one.
I based this circuit on a similar project by instructables user stacy k to sense when the door is opened. I used a magnetic reed switch. These are commonly used in security systems to monitor doors and windows. When the door is closed, the magnet pulls the contacts of the switch together, but when you open the door, this connection is broken. Next, you need to set up the arduino code.
I started by testing the code using an array of switches once that was working. I hooked up the actual sensors. Then i attached the sensors to the pipes with hot glue.
You’Ll probably need to make some adjustments. For instance, you can change the sensitivity factor in the code to calibrate your sensors. You can also experiment with different resistor values on the amplifier or you can try moving the sensors to a different location on the pipe.
In some cases, the pipes just don’t make enough vibrations to be easily distinguished from background noise. If this is the case, you can just replace the piezo sensors with a pair of electrodes that sense, the presence of water. You can mount them inside the tank of the toilet just below the water level, connect one wire to ground and connect the other wire to an input.
Pin then also connect the input pin to 5 volts with a high value resistor. When the wires are submerged, the input pin will read a low value, but when the toilet is flushed and the water level drops, the electrodes will no longer be in contact and the input pin will register a high value. Once your circuit is working to your satisfaction. You’Re ready to add the alarm, this can be anything that you can dream up.
I just went with a buzzer and a bunch of leds around a sign. First, i printed out a simple, didn’t, wash hand sign. Then i attached it to a couple of pieces of cardboard around the outside of the sign i poked holes for the leads of the leds. Then i inserted the leds at each location and wired them together. I connected them in groups of three leds in series that way i could power them directly from the nine volt battery that also powers, the arduino, the leds and the buzzer are activated by a single power. Transistor, that’s controlled by an output pin once the alarm is finished, mount it next to the restroom door and connect it to the arduino. The next time that someone uses the toilet and doesn’t use the sink.
The alarm will go off when they open the door to leave. Well, that’s how you can make a simple alarm that goes off whenever someone forgets to wash their hands thanks for watching and check back soon for more diy hacks and how to’s .