This is a project, made with EAGLE, of a generic control board that can read inputs, perform outputs switching and communicate with another device.
The license allows the use respecting certain requirements (see file license.txt included with the project), but the user takes full responsibility when using this information, related files or part(s) of them.
- It's highly recommended to use a fuse in the power input.
- Depending on the power input, the ground level may not match the ground of another device with which you want to connect a serial connection, the circuits must be checked.
The board features, as designed, are:
- 12VAC power input;
- Microcontroller AT89S51/52/53/8252/8253, operating at 11.0592 MHz. Each variant has different amounts of Flash, EEPROM (some models only) and RAM memories;
- 8 digital inputs, accept logic level 0 or 1 for input voltages of 0 V or 5V, respectively. the behavior is not defined for intermediate voltages;
- 2 adjustable detection level inputs. The reference voltage level is adjusted in hardware, between 0 V and 5 V, and the microcontroller can detect if the value of the input is higher or lower than the set level. Each entry has independent level adjustment and detection;
- 6 switched outputs with relays. Each output is a pair of contacts that can be closed (on) or opened (off), can switch a current of up to 0.5 A and voltage up to 12 V. Although higher voltages switching are possible, no study has been made of the maximum insulation voltage and load power should not exceed 10 W;
- RS232 serial communication;
- 5 V regulated output;
- Two voltage rectifiers, one exclusive for logic and communication part and another for the relays and the 5 V output.
Except where explicitly specified, all measures is for direct current (DC).