The ATmega168 project is a continuation of devices with DMX interface designed for set designers, people involved in the setting of events, musicians, etc. Our controller is able to control four servos, with which you can, for example, control lighting or animated elements of the scenery. After the transmission decay, the servos may be in their last state or assume the previously programmed default position. Recommendations: the cheesecake will be useful for moving objects on stage, switching filters or shutters in spotlights, controlling them or controlling valves.

It can also supply servomechanisms (JP5 jumper installed), but you must be aware that depending on the type and load, servomotors can draw a current greater than 1 A. In this case, provide the appropriate supply voltage, for example in the range of 4 … 6 V, with appropriate current capacity to J8 connector and remove the JP5 jumper. DMX data is converted to TTL levels using the U4 chip. The JP6 jumper enables attachment of line terminators.

JP1 sets the DMX address. Please note that the driver occupies four consecutive addresses. U3 decodes DMX data and generates impulses for servos. Pulses are generated in Timer 1 interrupts. The most important fragment of the initialization procedure is shown in Listing 1. Listing 2 contains the procedure for generating pulses for servos and a synchronization break.

ATmega168 The program uses Timer 0 to count the timeout of no transmission. If the commands do not reach for more than 1 second, the servos are set to the last position or will take the default position, stored in EEPROM.

DMX servo driver circuit schematic diagram

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