This paper presents a home automation module with programmable control instructions (PCIs). Although it is implemented by using a low-cost 8-bit microcontroller with only 8 Kbytes of ROM spaces, a time-sharing task scheduler and 10 PCIs are included in the firmware. Timer and counter control, logic functions, and temperature control are examples of PCIs. Thanks to the design of pseudo nodes, these PCIs can also be combined to implement more complex functions that home automation needs. These modules, up to 65536 theoretically, share the same IP address, and can be found over the network via different port numbers. No dedicated home server is necessary because the network communication (TCP/IP) is handled by the module. A remote control and monitoring software is also developed to let users control the home automation modules on the Internet. The programmable home automation module has a lower cost and better cost/performance ratio than current home automation modules