Fridge tuning

      I have an old fashion Romanian fridge. This is how it looks like:

     The idea is to add some new functionalites to it. I am thinking of led lights and some measurement device to measure temperature and maybe some thing else in the future.

Reed switch for detecting opened door:

Unlocked door notification

Some time people forget things. It's normal, but some time it is not good. Here i mean doors. If you leave door unlocked, someone can come in or your cat can get out. So the basic idea is to make a system that will announce(with buzzer) you that the door is unlocked.

The simplest way to do it, is to put a micro switch in your door lock. Something like this:

So when door is locked the switch is ON otherwise it is OFF.

Wireless water flow meter

In Romania (may be in other countries is the same) you have to give you water consumption to the administrator. This have to be done every month. By my experience, you always forget to do that. So let's help us.

So in this project i will try to build a system that sends your water consumption wireless. I will try to modify an ordinary water flow meter to fit my requirements. I found this on:

I liked it, because it has a compartment where i can put all electronics(including battery). Another advantage: it hase a magnet on one of it's weel, so i can integrate easily a magnetic sensor to measure water flow. This is where the magnet is placed:

and onother one:

Interfacing with TL-WR740N

     
In this post i will try to explain how to interface with a router. By interfacing i mean connecting another embedded devices to router. For example:

• tmperature sensor
• port expander
• external ADC(analog to digital converter)
• a radio module
• motors (servo, stepper)

Any router has GPIO. Actually all led's and buttons are connected to GPIO. We can use them. But there is a problem controlling them. You can't control the GPIO in a router the way you can control them in a microcontroller. You don't have precise timers to measure time between edges. Or you can, but i don't know how :D. So i will need to use a microcontroller, so i can do all the above thinks. It will not add big cost to ower system, because you can get a microcontroller for under 1$.  I will use PIC24 microcontroller, PIC24F04KA201. I am already familiar with ATMEL 8 bit microcontrollers. For a while i wanted to learn a 16 bit family from the microchip. So this will be a good start.

I will use TL-wr740N, because it's chip :) .This is how it looks like inside:

        

Metro alarm

The ideea of metro alarm is to notify the user about his metro station, when he is sleeping or hardly thinkink. Actually this is a phone based application, that countes stations. The main problem here is: how can we count station? How does the phone know when you arrive to the station. Well there are a few posibilities that have been explored by the people.
   -  You can do voice recognition, so the phone can listen using the microphone and to process the voice captured. I see here 2 problems. First one is that you have to make some powerful calculations, that will consume your battery. Second is the background noise.
    -  My ideea (i am sure not only mine), is to use accelerometer. So when the train accelerates/decelerates you will see some changes on one of the axis. The problem here is that the phone have to be in the same position, or you can make adaptive algoritm, to automatically adjust the settings when you move the phone, but i think it is to complicated.