Realtime filtering on a microcontroller, with dynamic cut off frequencies Is it possible to dynamically filter a signal in realtime on a microcontroller? 

What I mean by dynamically is to change the cut off frequency of the filter on the fly. 

I have some DSP knowledge and realize that I probably do not have the computational power to do an FFT on the fly. Instead I should be looking at creating an IIR or FIR filter that I can continually convolve with my signal. 

The issue is now whether or not I have enough computational power to generate the filter coeffecients quickly and then convolve with the signal. I'm guessing that because of this I'm going to have to be very lenient on the response of the filter which is ok for my application. 

I have looked at algorithms such as the Remez Exchange algorithm and believe this may be able to work but am not sure. I wanted to check before I start the lengthy process of implementing whether or not I am on the right track.
You can pre-compute the coefficients for a bunch (say $N=1024$) different cutoff frequencies. If your application doesn't need to provide fine control over the cutoff frequency, just read from your table and you're done. This works best if you have a lot of ROM and/or you use short FIR or IIR filters.
If you need finer control than those $N$ values, and if the relationship between your coefficients and cutoff frequency is well-behaved (ideally, monotonic), you can use linear interpolation within the pre-computed table of coefficients. This works best with well-behaved structures like state-variable filters - for which the coefficients are monotonic functions of the cutoff frequencies, and which do not get unstable when modulating them at fast rates. This is a very common problem in musical audio applications (equalizers, synthesizer analog filter emulation...). If you use other filter topologies, make sure that they cannot get unstable when their coefficients are changed "in mid-flight" - to me, this is a harder problem than actually computing them.