I'm trying to control the speed of a computer fan using the radio input from an RC transmitter/ reciever. The PWM output of the reciever is 1ms to 2ms high and 20ms low, so 10%-20% duty cycle. The computer fan requires a 30% to 100% duty cycle, at 25khz (about a 40uS pulse) I was thinking of using a 555 timer (astable, monostable wouldn't work) but that's a minimum of 50% duty cycle. Control this with a potentiometer turned by a servo. Are there any other ways to do this? I wouldn't mind getting into micros because I want to learn that at some point but I need to learn how to code. I can write computer code so the concepts are sorta there but language is an issue. Nothing impossible please, I'm only 16, I have most of the knowledge but not all of what a fully aged person would. Thanks in advance.