A.M.
Have you been diagnosed with PCOS? How irregular is you cycle? If you are much greater then 30 days there is a high chance you are not ovulating at all and most of the preditor will never show a high, been there. The monitor is the electronic one but it is about $100 or so, it is the Clear Blue easy. However if you are not ovulating or you have PCOS, you will most likely not show a peak on the monitor.
Have you considered talking to your OB and maybe doind some additional work to help you. There is some very simple steps that your OB can do. i.e. an HSG to make sure your tubes are open, Clomid, etc.
I have PCOS, take 1500mg of metformin. I have a 4 year old boy, my mircle and have been TTC #2 for 3 years with 2 MC's during the process.