801S Vibration sensor. 2015-10-01

I was asked to design a simple vibration sensor module for a vehicle. The module was intended to trig a gps tracker. The tracker has built in functions for this but the function is only enabled when the tracker is in normal mode. The current consumption of the tracker in normal mode is specified to ~65mA which is alot if the vehicle is not used every day. In standby mode the tracker consumes only a few mA and can be trigged/enabled by pulling an IO high. And here is where the 801S sensor module comes in.

It basically detects a shock or vibration and enables the tracker. It uses as mentioned the 801S sensor with the recomended application circuit. For the logical "intelligence" i used a PIC12F675 which monitors if for example ignition is ON/OFF. There is to mention also a "leave time" of around 5min when the vehicle is turned of,  the sensor module cannot trigger before this time has elapsed.

The only cons with this module is if the vehicle is lets say on a boat it will trig the tracker, This is solved by only having maximum two trigger events possible. To reset the module and get two new events the vehicles ignition must be toggled once.

By this solution the module and tracker together consumes around ~11mA.

With this project i tried out how it works to send gerber files to a PCB manufacturer and get a real PCB's done profesionally.

Security System. 2015-06-01

A friend rebuilt his existing carport to a fully closed garage. Of course he needed to secure it with proper security system that has both theft and fire surveillance. Also i connected this system to his already home surveillance system so that it vill be connected to a security company.

The main features are:

-Two separated NTC sensors mounted in the ceiling above each car for fire detection. Also there is a internal NTC that monitors the temperature of the alarm system itself.

If fire is detected it will activate main home security system by wire. If internal heat is detected there will be an audible tone from built in buzzer.

-Built in backup battery.

-Mains power is monitored and if it's disabled there will be an audible tone from built in buzzer.

-Different logical dependencies to determine if there is doors are forced open or it's a legal entry.

-7seg display for showing status.

-Output for external siren.

-Keylock for enable/disable.

NTC sensor used for fire detection mounted on ceiling. If temperature is above 55degC it will be considered as fire by the system

Setting timing and delays in the code was easiest to do with the real door hooked up to the PCB.

Micro switches determines if the garage door is fully open or closed