In this post I have explained how to use Bluetooth technology for transmitting PWM wirelessly, the circuit application could be used for controlling various appliances such as motors, lights, RC gadgets etc using your Android phone.
The Bluetooth PWM Transmitter
In one of my earlier posts I explained how to hack and modify a Bluetooth headset for making a Bluetooth Home-theater system, the same concept can be employed here for controlling a preferred appliance such as a motor using Bluetooth PWM.
There are actually two options to transmit Bluetooth PWM, one is by using a specialized Bluetooth transmitter module and a function generator circuit, or a much simpler modified Bluetooth headset gadget.
In this article I have explained how the second option could be used for implementing the proposed Bluetooth PWM motor controller circuit.
The idea is actually as simple as integrating the Bluetooth headset speaker wires with a mosfet or BJT motor driver stage, that's all.
The details can be seen in the following figure.
The above set up shows an external PWM motor driver simply configured using some diodes, an opto-coupler and a BJT stage.
The PWM from the Bluetooth Headset is passed through a bridge diode network and then applied at the input of an opto coupler.
The output from the opto coupler is finally fed to a motor driver stage.
Now as the PWM from Bluetooth headset is changed, the motor responds to the PWM and correspondingly changes its speed.
How to Obtain the PWM Transmission for the Bluetooth Headset
The PWM transmission for the Bluetooth headset can be obtained from your Android phone.
For this you may have to install any standard PWM generator application and then "pair" it up with your Bluetooth headset.
Next, you would be prompted to adjust the duty cycle, PWM, frequency etc within the application, which you can fix as per your preferences.
Once all these initial set ups are completed, the PWM transmission for the Buetooth headset could be initiated for executing the motor control operations.
The PWM or the frequency could be changed as per your wish and will, from your android phone application whenever the speed of the motor is required to be altered.
This concludes our tutorial on Bluetooth PWM motor controller circuit, which looks extremely simple and useful, thanks to the all latest technology like android applications and Bluetooth features.