crop harvesting machine (mini combine harvester)

I want the idea of making a combine harvester .which can be Ox drawn  and can be used to harvest crops such as maize .wheat, soya beans and other  and it has to be cheap and affordable  I'm doing diploma in plant engineering

Considering the number of operations involved, it is unlikely that a workable machine that can be pulled by a couple of oxen can be developed. In the early days combines were pulled by teams of twenty horses or mules.

This is not exactly what you wanted @cuthbert tafirenyika , but may give some clues:

http://www.kscst.iisc.ernet.in/spp/41_series/40S_awarded_&_selected_projs_further_devpt/40S_BE_1364.pdf