Motorized blind opener

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  overall circuit

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  closeup of the h bridge

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  the code

In this project, I aimed to create a device which would automatically open the blinds when it is bright outside and close them when it’s dark. This system provides sunlight during the day while also maintaining your privacy at night which is something that I would find useful in everyday life. Since all building was virtual, it wasn’t difficult to complete this project and it worked nearly from the first prototype. I decided to use a simple DC motor paired with an H-bridge MOSFET configuration in order to drive it forwards and backwards. Each MOSFET was connected to a digital pin on the Arduino Uno which I was using. To measure the light intensity, I simply used a LDR with a pulldown resistor on the analogue measurement pin. To detect when the blinds are in the up/down position and stop the movement, I used two pushbuttons. Similarly, I placed pulldowns on the buttons as well. The software essentially detects when the device is in one of three states; dark but open blinds, light but closed blinds, and when the blinds are in the correct position for the time being. Depending on the state, it acts accordingly by activating each MOSFET at the correct time to move the blinds up, down or stop the movement entirely. A 4 AA cell battery pack provided the extra current necessary for the motor to operate. The most difficult part of this project was dealing with how incredibly laggy tinkercad got after I placed more than 2 MOSFETS into the circuit. On some occasions, I would have to a few minutes before the simulation would start. This made the process far more difficult. This may be due to my computer. If I was building this in person, I would make a small 3D printed case to house the electronics and make it neater. I would also consider creating a separate housing to mount outdoors so that a more accurate light intensity measurement could be achieved. This extra station could then be connected via bluetooth or a long wire to the main hub that contains the motor.

Built With

• arduino
• ldr
• mosfet
• motor