Digital Thermometer using ARM Cortex M3

Digital Thermometer using ARM Cortex M3

Digital Thermometer using Temperature Sensor LM 35 is most accurate and precise up to 0.4 degree Celsius. LM 35 is the temperature sensor with 3 terminals seeing from flat end terminal 1 is Vcc which should be connected to 5 V or 3.3 V  and terminal 2 is V out which is the analog output which should be connected to ADC. Terminal 3 is ground.

       As ARM Cortex M3 operates at CMOS level Vcc should be 3.3 v (max) and Vout is the analog output pin which should be connected to Analog to Digital Converter  also 100 ohm resistor should be connected to Vout and Gnd.

Input should be taken from Vout and conversion formula is 10millivolts per degree.

Temperature in (Degree Celsius)=( (3.3*d/1023)*100);

As per Demo Initially glass with Ice water is placed near sensor and then it is removed to observe variation in surrounding temperature.

Speed Control of DC motor using ARM

Speed Control of DC motor using ARM 

DC Shunt Motor is the constant speed motor whose speed is directly proportional to the applied voltage. Resistor(Starter ) based speed control technique has few limitations like excess power dissipation. In the process of controlling speed  excess voltage is dropped across resistor which is not the efficient way of doing it. Alternate way to control speed of DC motor is by using Pulse width Modulation. Systick can be used to generate PWM. Bi-directional speed control of DC Motor is as shown.

  

Bi directional speed control of DC motor is possible based on state of GPIO 1, GPIO 2

Automatic Street Light control using ARM

Automatic Street Light control using ARM

Power is a non-renewable source which has to be conserved and utilized in an efficient way. Most of the time we observe that street lights has to turned on by someone during night  and it has to be turned off  on the following morning. If he forgets to turn them off Street lights will run even during day time which leads to huge power loss. This problem can be well addressed by this project.

Considering above mentioned aspects Automation in turning on/off of street lights can be done by using sensors like LDR, IR etc

1. Street Light has to be turned on automatically when it goes dark 

2. Only if someone comes in that vicinity it has to be turned on.

3. Street Light has to be turned off automatically when no one in that vicinity, when surrounding  visibility is good.  

    

LDR , IR can be used in conjunction to solve it.

Analog Input can be taken from A in

when Light falls on LDR- it offers low resistance of (10 -50 ohms) ideally zero so there will be low voltage drop across LDR. 

when no light falls on LDR it offers high Impedance of (10M ohms) ideally infinite impedance so it acts like open circuit and entire voltage appears across LDR.

IR - LDR can be used together(Logical AND) to control street light

For demo i used only LDR
Observer Led it will be off when External light is ON when light falls on LDR
Led will turrn on when External Light is OFF.

code- Download

Electronic Voting Machine Using ARM

Electronic Voting Machine Using ARM

Electronic Voting machine can be implemented using ARM  it involves Keyboard interface and a timer to reset keypad after casting vote and display unit to display vote status.

Keypad can be any input device here i have considered DTMF Decoder so that Mobile phone keypad can be used as input unit.Systick Timer to generate delay and Display unit to display vote status, voting percentage also polling results.