This microcontroller project was design and implemented by Wichit Sirichote from thailand. the device that controls home's night light, air-conditioner,etc. The device is a Miniature Real-time Controller. The circuit uses only three chips, a 89C2051, DS275(or MAX232), and 74LS07 open collector driver. The scheduler for time on/off of 6-channel output can be made by downloading from PC and saved into onchip RAM. Each output provides a 20mA sinking suitable for driving a homemade opto-triac or big solid-state relay for heavy load.
Hardware
A Microcontroller AT89C2051 with a low-cost X-tal 3.579MHz runs timer6.hex. The 6-channel output is P1.2 to P1.7 driving with sink current. A 74LS07 open collector provides approx. max 20mA @12V suitable for driving a homemade opto-triac shown in Figure 2. Two signal diodes, 1N914, provide simple backing up supply for the AT89C2051. Since RST uses simple RC circuit, there is no brownout protection and reset switch thus when the controller operated with battery for long time, the chip may knock. Simply take the battery out and put them again. The RS232 level converter, instead of DS275, any converter may use, or simple circuit using two transistors.
Link: source
Free Magazines
Download this guide to learn and understanding everything you need to know about the Raspberry Pi computer, system specs, the software it runs and the amazing project based on this little PC.
PEI is the leading magazine for the global electric power generation and transmission industry. PEI provides articles on new technologies and installations and analysis.
Subscribe Fof Free!
EDN magazine provides how-to solutions for design engineers in the electronics industry. Engineers turn to EDN because they know they will always find valuable design techniques that they can use to do their jobs faster.
Subscribe Fof Free!
More Free Engineering Magazine
Headlines
1 Comentar:
Post a Comment