I want to create a project, where I can control the speed of a fan remotely (similar to what we did in project 8 of the Bolt IoT training : LED Intensity Control).
According to the above link, is a relay enough to help connect the fan to the bolt wi-fi module?
I’d like to know of what voltage of fan should i purchase for this project? Should I use a 5V DC fan or a 12V fan etc such as this one:amazon.in/CentIoT®-Brusless-Cooling-Suitable-Raspberry/dp/B07RZM3Z8J/ref=sr_1_6?keywords=5v+dc+fan&qid=1571239573&sr=8-6
I’d be grateful if someone could help me in answering the following questions:
a) Should I purchase a 5V or a 12V etc fan? what voltage would you recommend or does the voltage of fan matter if we use a relay?
b) How to connect a fan to bolt wi-fi module? what would be the connections.
c) What necessary additional equipment should be used? such as a relay or driver etc.
Usually a relay module won’t work for any intensity control application, as a relay understands only two values high or low. It can be off or on at a particular time . As in speed control setup a range of voltage is used from 0v to 3.3v , and relay works on either 0v or 3.3v.
One possibility is that you can use a 5v fan (as 3.3v fans are not easily found ) directly with the bolt module , but i won’t suggest you to do that. As fan can draw much more current than the capacity of bolt module and can burn it.
You can use a “dimmer circuit” for this project which has a relay module along with some other electronic components.You can connect the fan with relay and the dimmer circuit with the bolt module. You can buy either a 5v fan or a 12v fan for this project, both will do their jobs. Make sure to use the proper power source also.
The right way of going about this is to use a motor driver circuit with pwm control input.
An example of the same is given in the link below
For the circuit in the example, you can use a any motor with a voltage range of 5 to 20V.
You can do the connections as follows
Pins of the motor connected to 1 and 2 terminals (Green with screw) of the motor driver for the same motor. I would suggest connecting to terminals with 1 and 2 written infront of them, with MA written between 1 and 2. (MA stands for Motor A).
Your power supply for the motor should be connected to the + and - terminals. Ensure that the positive of your supply goes to + terminal and gnd goes to -ve terminal.
Gnd of the Bolt WiFi module should be connected to Gnd pin (bent pins) of the motor driver circuit.
3.3v of the Bolt WiFi module should be connected to VCC pin of the motor driver circuit.
You will need to connect 1 digital IO pin of the Bolt WiFi module to each of the pins A1, A2 and EN-A of the motor driver circuit, if you want to control both the speed and the direction of the motor.
You will have to use the pins connected to A1, and A2 as and set them to HIGH or LOW, using the remote api, (or the digital LED control code) to set the direction of the motor.
You will have to use the pin connected to EN-A as Analog output, and set it to the required PWM value to match the speed that you want the motor to run at.
Most motor driver circuits have similar pins. You could go for a different motor driver circuit if you want, but do look into which of their pins functions as mentioned above.