ive also found an imterestimg cmos ic. : the cd 4066 quad switch. basicly it 4 switches integrated into one small 14 pin dip ic. you ask how this may be useful? i ll explain.. say you have a row of triggers with physical switches. you have to drill holes for everyone and wire everyone and have faceplate realeastate for each one. thats all well and cool, but depending on how much money u want to spend.. can be costly and time consuming depending on style of switch.. so ive been thinking of this chip for a drum programmer unit. basicly a large trigger sequencer with a ton of rows for triggering drums and envs or whatever. say 4-8 rows depending. so i can have one row of 16 step switches (like the 808-909) and then selelct between the instrument rows for their use. the only issue im trying to solve is one of power to that row after selection is done..
the chip uses and the vdd volatge as the on status for the switch input and the vss voltage (or lack of) for the off. basicly system power and ground. mine would be +12 an ground in this case. i guess i can just switch the power from another source to "hold" the stauts of each switch after i remove the row from the programmer circuit. like a "lock" switch. another issue is that upon powering down all sequences will be lost. but it would enable me to put all of this into say 3 or 4 rack spaces then for 8 rows of gates and triggers. one row of programmer switches (reeeeeal nice ones) and then a 4-8 x 16 grid of leds that correspond to each rows triggering status and one row of counter "current step" leds. just an idea....
also this would involve me going one more step into all of this stuff and etching my own boards. it would only be wise to do this for such a large amount of ic wiring and repeating circuits. and size as well. im working on how to make each row independant lengths and modes as well. (bi directional, reverse, random etc) it would be a seriously ridiculous analog drum programmer unit, that would be super original.
Monday, November 8, 2010
so ive sort of take everything from the first sequencer on here and added all of it to the new one thats about 85% done. additional features : gate hold per sequencer to slur-tie your gates together for envelope holds. selectable per-step portamento (aka "slide" ) like on the tb-303/csq-600/sh-101 sequencers. and last nbut not least 3 sets of digital line inversions for cv channel A, B and Slides! ill have some new pics inthe next couple days.. its been quite a consuming wiring task along with simply figuring out how it needs to be done for all this to happen. im sure they'll be lots of bugs to work out . i never plan on it working right off the bat:) heres a pic of the control line wiring that needs to be done to make this happen.
the other image is the truth tables for cd4067 multi-de multiplexer ic. it is the translation of the 4 bit digital line and how its affected by the inversion of its pulse .. and what that means in reality to the sequencer running. basicly it does nested looping!!!! so it makes really sick variations of your pattern. 16 of them! when used in the "bi derectional" and "reset" modes, this does even weirder and cooler things. i havent been able to count the permutations yet.lets just say theres alot.