Curry powders vary greatly from region to region as the local population tends to add or subtract spices not to their liking or even available. That said there is often some commonality between recipes in their base flavours and you can make a very good, simple curry powder with spices that you may well have at your disposal on the spice rack. The dried chillies add enough heat to this curry powder for most peoples appetites but if you do want to go hotter then I recommend a teaspoon or two of good quality chilli powder to liven things up.
This recipe will make between 5 and 6 tablespoons, enough for 10 meals or so depending on your recipe. Use within 3 months.