For NiCd the constant current algorithm works well. If there is a thermistor on the battery you can use high charging rates, while monitoring the temperature. Otherwise, you will have to use a slow charging method.
Take a look at these two projects:
NiCad AA automatic charger **broken link removed**
NiCad 87C751 charger **broken link removed**
The second one is probably a little bit overdone ..
The mcu 87C751 can be replaced with any microcontroller of 8051 core, and software in C is included ..
Regards,
IanP
Thank you all.the pages were very helpful.I am studying them now. This is for my final year project.Im supposed to build a usb interfaced battery charger for Ni Cd and Ni Mh batteries,controlled by philips lpc 2148 which is an arm 7 micro controller with usb 2.0.The charger is supposed to draw power from the usb port,can anyone help me with the design of the charging device.