You cannot make your own and must be purchsed from Curtis as a kit. Also the software floating around on the web will not work with the 1238. It must be the latest version. Best bet is to buy the 1311-4401 OEM version of the hand held programmer which works real good with 1238 available here firstname.lastname@example.org
. You will not believe how much better you can program the 1238 to control a AC motor. Probably the most requested feature is setting up brake regen or brake current. There is a differant need in the programming of the regen/brake depending if you are clutch or clutchless. Both work real good.