5.Specification

The_​​idea_​​and_​​requirements_​​generated_​​in_​​chapter_​​4_​​are_​​further_​specified,_{​ ​​}and_​​low(er)_​​level decisions_​​are_​​made_​​to_​​create_​​a_​​clear_​​definition_​​of_​​the_​​project_​​to_​​be_​​realised._​​This_​​chapter

includes_​​a_​​specification_​​of_​​the_​​system_​​and_​its_{​ ​​}functionalities,_​​followed_​​by_​​a_​​further_​​specified_​​light plan_​​and_​​addressing_​​of_​​light_​​fixtures.

5.1_​​System_​​specification

The_​​hardware_​​used_​​by_​​the_​​existing_​​lighting_​​system_​​in_​​the_​​SmartXp_​​and_​​the_​​operation_​​thereof_​​is explained_​​and_​​supplemented_​​with_​​descriptions_​​of_​​the_​requirements_{​ ​​}that_​​will_​​need_​​to_​​be_​​met_​​in the_​​realisation_​​phase_​​in_​​order_​​to_​​overcome_​its_{​ ​​}challenges._​​Next,_​​the_​​functions_​​the_​​system_​​will have_​​are_​​described_​​and_​​explained_​​through_​​schematic_​​drawings.

5.1.1_​​DMX_​​light_​​system

The_​​(spot)_​​lights_​​that_​​were_​​already_​​installed_​in_{​ ​​}the_​​SmartXp_​​use_​​the_​​DMX512_​​[16]_​​(digital multiplexing)_​​protocol_​​to_​​set_​​lighting_​​parameters._​​This_​​protocol_​​makes_​​use_​of_{​ ​​}a_​​single_​​signal string_​​for_​​all_​​lights,_​​which_​​are_​​daisy_​​chained_​​to_​​each_​​other_​​so_​​that_​the_{​ ​​}single_​​signal_​​reaches_​​each fixture._​​The_​​signal_​​is_​​composed_​​of_​​channel_​​signals,_​​each_​​light_​​fixture_​​is_​​set_​to_{​ ​​}an_​​adress,_​​which_​​is its_​​starting_​​channel._​​For_​​example,_​​a_​​4-channel_​light_{​ ​​}(usually_​​red,_​​green,_​​blue,_​​bright)_​​set_​​to address_​​100_​​will_​​use_​​the_​​values_​​of_​​channels_​100-103_{​ ​​}and_​​sets_​​its_​own_{​ ​​}parameters_​​to_​​the_​​values of_​​those_​​respective_​​channels._​​In_​​order_​​to_​make_{​ ​​}use_​​of_​​the_​​existing_​​lights_​​and_​​implement

additional_​​fixtures_​​it_​​is_​​required_​​for_​​the_​​system_​to_{​ ​​}be_​​developed_​​so_​that_{​ ​​}it_​​controls_​​lights_​​through DMX512.

5.1.2_​​System_​​control

In_​​order_​​to_​​control_​​the_​​lighting_​​hardware,_​​a_​​programmable_​​device_​​that_​​is_​​able_​​to_​​receive_​​context input_​​and_​​process_​​it_​​to_​​output_​​signals_​​to_​hardware_{​ ​​}is_​​required._​​After_​the_{​ ​​}control_​​device_​​has_​​been connected_​​to_​​the_​​lighting_​​system,_​​use_​​cases_​​can_​​be_​​programmed_​according_{​ ​​}to_​​lighting_​​conditions that_​​are_​​precisely_​​determined_​​by_​​Heleen_​​Kok,_​converted_{​ ​​}into_​​values_​​that_​​match_​​the_​​channel_​​and address_​​settings_​​of_​​the_​​fixtures._​​Each_​​use_​​case_​​will_​​consist_​​of_​​a_​​set_​of_{​ ​​}DMX_​​controls_​​that_​​are wrapped_​​into_​​functions_​​so_​​that_​​each_​​use_​case_{​ ​​}can_​​be_​​called_​​individually._​​Even_​​though_​​this system_​​will_​​not_​​be_​​fully_​​developed_​​within_​​the_​scope_{​ ​​}of_​​this_​​project,_​it_{​ ​​}is_​​necessary_​​for_​​Heleen Kok’s_​​testing_​​purposes,_​​and_​​desirable_​​for_​​the_​usability_{​ ​​}of_​​the_​​system,_​​that_​​all_​​determined_​​use cases_​​are_​​programmed_​​and_​​executable_​​by_​​the_​​program.

The_​​accuracy_​​with_​​which_​​the_​​system_​​is_​​able_​to_{​ ​​}determine_​​use_​​cases_​is_{​ ​​}dependent_​​on_​​the_​​right use_​​of_​​context_​​sources._​​In_​​order_​​to_​​make_​​use_​​of_​​the_​​system_​​as_​soon_{​ ​​}as_​​possible_​​and_​​during development_​​there_​​are_​​two_​​context_​​determinants_​that_{​ ​​}must_​​be_​implemented_{​ ​​}first._​​The_​​two

context_​​sources_​​chosen_​​are_​​the_​​SmartXp’s_​​schedule_​​and_​​user_​​input,_​because_{​ ​​}of_​​their_​​respective accuracy_​​and_​​flexibility._​​The_​​schedule_​​enables_​​the_​system_{​ ​​}to_​​interpret_​​what_​​general_​​use_​​case_​​is going_​​on_​​with_​​high_​​accuracy,_​​since_​​it_​​is_​​solely_​​dependent_​​on_​​the_​​events_​that_{​ ​​}are_​​put_​​in_​​the schedule._​​If_​​a_​​use_​​case_​​occurs_​​that_​​is_​​not_​​scheduled,_​​or_​​if_​​a_​​new_​​type_​​of_​​use_​​case_​​that_​​was previously_​​unthought_​​of_​​occurs,_​​lighting_​​conditions_​​can_​​be_​​set_​​manually,_​hence_{​ ​​}the_​​choice_​​of

user_​​input,_​​or_​​manual_​​override,_​​as_​​a_​​second_​​context_​​source.

5.1.3_​​System_​​functionalities

The_​​system_​​to_​​be_​developed_{​ ​​}must_​​be_​​able_​​to:

- Use_​​a_​​control_​​unit_​​that_​​is_​​able_​​to_​process_{​ ​​}data_​​from_​​context_​sources_{​ ​​}to_​​control_​​the_​​lights through_​​DMX.

- Alter_​​lighting_​​conditions_​​according_​​to_​​a_​set_{​ ​​}of_​​output_​values_{​ ​​}per_​​use_​​case. - Switch_​​between_​​use_​​cases_​​by_​​autonomously_​​checking_​​the_​​SmartXp’s_​​schedule. - Allow_​​the_​​user_​​to_​​manually_​​set_​lighting_{​ ​​}conditions_​​through_​a_{​ ​​}user_​​interface,_​​preferably

online.

The_​​diagram_​​in_​​​Figure_​​5_​​​shows_​​the_​relations_{​ ​​}between_​​different_​​components_​​of_​​the_​​system_​​and how_​​they_​​relate_​​to_​​the_​​user.

5.2_​​Light_​​plan_​​specification

The_​​light_​​plan_​​as_​​conceptualised_​​in_​​chapter_​​4.5_​​is_​​further_​​specified,_​​after_​​which_​​all_​​light_​​fixtures are_​​addressed_​​in_​​the_​​DMX_​​universe.

5.2.1_​​General_​​light_​​plan_​​second_​​iteration

After_​​discussing_​​the_​​concept_​​light_​​plan_​with_{​ ​​}client/supervisor_​​and_​project_{​ ​​}partner,_​​a_​​few

alterations_​​were_​​made,_​​see_​​​Figure_​​6_​._​​Further_​​specifications_​​are;_​​the_​​RGB_​​spots_​​in_​​sections_​​1-3 are_​​directed_​​downwards_​​on_​​the_​​tables,_​​the_​​white_​spot_{​ ​​}lights_​​in_​​section_​1-2_{​ ​​}are_​​directed_​​at_​​the white_​​wall_​​panels_​​(on_​​the_​​upper_​​side_​​of_​​the_​image),_{​ ​​}the_​​white_​​spot_​​lights_​​in_​​section_​​3_​​are_​​directed downwards_​​to_​​the_​​lecturer,_​​the_​​moving_​​heads_​are_{​ ​​}both_​​directed_​​downwards,_​​the_​​RGB_​​spots_​​at both_​​entrances_​​should_​​be_​​directed_​​into_​​the_​​hallways_​​so_​​that_​​their_​​colour_​​may_​​be_​​noticed,_​​without being_​​bothersome._​​Furthermore,_​​an_​​LED-strip_​​is_​​added_​​on_​​the_​​upper_​side_{​ ​​}of_​​section_​​four, mounted_​​on_​​the_​​handrail,_​​meant_​​to_​​use_​​colours_​​which_​​indicate_​​whether_​​the_​​area_​​may_​​be_​​used and_​​what_​​level_​​of_​​audio_​​is_​​allowed_​​to_​be_{​ ​​}produced_​​(see_​​Heleen_​Kok’s_{​ ​​}project_​​report_​​for_​​further details).

5.2.2_​​Addressing_​​light_​​fixtures

DMX_​​lighting_​​systems_​​work_​​with_​​so-called_​​‘universes’_​​that_​​can_​​control_​a_{​ ​​}maximum_​​of_​​512 channels._​​This_​​does_​​not_​​mean_​​that_​​512_​​light_​​fixtures_​​can_​​be_​​installed,_​​as_​each_{​ ​​}light_​​takes_​​up_​​a couple_​​of_​​channels,_​​for_​​example_​​for_​​its_​​red,_​​green,_​​blue_​​and_​​brightness_​​values_​​(see_​​chapter_​​5.1). Counting_​​the_​​amount_​​of_​​light_​​fixtures,_​​including_​​two_​​LED_​​strips,_​​the_​​number_​​is_​​over_​​40._​​Assuming at_​​least_​​four_​​channels_​​are_​​used_​​per_​fixture,_{​ ​​}40_​​fixtures_​​individually_​​addressed_​​would_​​take_​​up more_​​than_​​160_​​channels._​​Even_​​though_​​this_​​does_​​fall_​​within_​​the_​​limits_​​of_​a_{​ ​​}single_​​DMX_​​universe,_​​it is_​​too_​​extenstive_​​to_​​manage_​​this_​​in_​​software_​​programming,_​​at_​​least_​​within_​​the_​​scope_​​of_​​this project.

The_​​solution_​​is_​​the_​​design_​​as_​​seen_​​in_​​​Figure_​​74_​​below,_​​where_​​a_​​large_​​amount_​​of_​​fixtures_​​are grouped,_​​the_​​addresses_​​008,_​​001,_​​015,_​​022,_​​029,_​370,_{​ ​​}360_​​and_​​350_​are_{​ ​​}applied_​​to_​​four_​​fixtures each._​​For_​​clarification,_​​this_​​does_​​not_​​mean_​that_{​ ​​}they_​​are_​​individual_​​DMX_​​universes,_​​they_​​are groups_​​of_​​fixtures_​​set_​​to_​​the_​​same_​​address,_​​all_​​within_​​one_​​universe._​​This_​​means_​​that_​​several lights_​​take_​​the_​​same_​​channels_​​of_​​the_​​DMX_​​string_​​as_​​their_​​input,_​​as_​their_{​ ​​}starting_​​adress_​​is_​​shared. Important_​​to_​​note_​​is_​​that_​​grouping_​​fixtures_​​by_​address_{​ ​​}only_​​works_​​if_​all_{​ ​​}light_​​fixtures_​​within_​​the group_​​are_​​of_​​the_​​same_​​brand_​​and_​​use_​​the_​​same_​​channel_​​settings._​​The_​choice_{​ ​​}of_​​which_​​lights_​​to group_​​was_​​made_​​in_​​consultation_​​with_​​Heleen_​​Kok.