I am looking at using a MOSFET Module to switch a load from a Radio controller; transmitter. The signal from the Transmitter is PWM, Can I connect the signal pin directly to the Receiver or do I need to use an Arduino. Any help would be much appreciated.
The module is shown below:
What type of PWM? Radio controllers often output a particular type of PWM intended to control servo motors. This will work with MOSFET modules, but will only give a small range of control, like 10% to 20%. You may need the full 0% to 100% for your MOSFET module.
The Radio Control signal consists of a pulse every 20ms.
In the Arduino Servo library the example 'Sweep' goes from a 0.54ms pulse every 20ms (2.7% duty cycle), up to a 2.4ms pulse every 20ms (12% duty cycle).
The following traces are taken from the Arduino IDE examples 'Sweep' from the Servo library, and 'Fading' for the PWM signal.
The same time base is used in both cases.
'Sweep':
'Fading':
See the difference?
Which of these do you want?
Yes, you will need an Arduino to do what you want.
An UNO or Nano would do
You haven't told us what the load is.
If the load was an LED for example,
using the radio control signal alone, you could alter the brightness between 'dim' and 'very dim'. Not very useful.
Using the Arduino PWM signal you could alter the LED brightness from 'off' all the way up to 'full brightness'. More useful.
Using an Arduino, you can read the Radio Control signal, and generate a PWM signal based on the RC signal's pulse width.
You can use the function pulseIn() to measure the RC pulse width, and the use the map() function to get the PWM signal to go from 0% to 100% duty cycle.
Many thanks for your speedy reply, not sure what type of PWM signal, and I have tried to find out but no joy as yet. All I know is that the pulse has a minimum of 1000 microseconds and a maximum of 2000 microseconds. My initial thought was to use an ATTiny 85 to process the PWM pulse and dependant on the length of the signal, switch on or switch of the load, but when I saw that the module could handle a PWM signal, I thought I could do away with the ATTiny 85.
No you still need the ATTiny85
To be honest, I'm not really sure, I just want to switch a load on and off. From what others have said, I do need and Arduino/ATTiny 85 and I am happy that I know what I am doing with that. Many thanks for taking the time to upload the videos.
Many thanks, for confirming that. I know what I need to do now.
Thank you for your reply, I will be using an ATTiny 85 and will use the pulseIn() function. I won't need the map() function in this instance but it is handy know for future projects.
That is easy to do.
I think you knew that from the very beginning.
I kind of guessed that would be the case but thought the module might have accepted the PWM signal from the R/C Transmitter.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.
