portable-line-mixer

portable-line-mixer

A compact line level audio mixer.

Volume control via Digipots.

TODO

• Export BOM and price out parts
• CODE

Extra parts

• 772-E25-103RYY1 norcomp db25 IP67 connector male
• 772-E25-203RYY1 norcomp db25 IP67 connector female (for panelmount)
• 967-025-010R011 norcomp db25 IP67 backshell for cable
• SFP6725 norcomp adhesive seal db25 size
• 967-025-CAP norcomp ip67 sealing cap
• 160-067-004R034 norcomp db25 hardware kit
• 767KS1(X) 0.084 [2.1] id/od sealed locking power plug switchcraft
• L722AS 0.08 [2.0] id/od sealed locking power jack switchcraft (these sizes are compatible with high amperage version)
• JCAP power jack cover
• 35FM3AULS - Sealed locking 3.5mm panel mount jack switchcraft
• 35HDLBAU(S) 3.5mm sealed locking plug switchcraft (S=0.175 diameter cable, no S=0.29 diameter cable)
• NE8FDX-P6-W IP rated ethercon connector Cat6A shielded neutrik
• NE8MX6 Cat6A ethercon cable connector neutrik

Max Power Consumption figures

Component	Quantity	Current	Voltage	Total Watts
4x Op Amp	1	2.8mA	±12V	67.2mW
digipots	8	2uA, 5uA	+5VD, ±5VA	0.48mW -> 0.5mW
microproc	1	27mA	5V	135mW
Total				202.68mW
ref total				500mW

References / sources

Code

• http://playground.arduino.cc/Main/RotaryEncoders#Example1
• https://www.arduino.cc/en/Reference/Wire
• http://gammon.com.au/interrupts
• https://www.arduino.cc/en/Reference/AttachInterrupt

Physical Design

• https://m.reddit.com/r/arduino/comments/1tr7in/question_i_burned_out_this_small_smd_component_on/
• https://www.arduino.cc/en/Hacking/PinMapping32u4
• https://www.arduino.cc/en/Main/ArduinoBoardMicro
• http://www.atmel.com/Images/Atmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf
• http://sound.whsites.net/articles/capacitors.htm
• http://electronics.stackexchange.com/questions/210376/details-on-pcb-layout-for-microcontroller
• http://electronics.stackexchange.com/questions/210580/pcb-microcontroller-layout-in-a-mixed-signal-system
• http://electronics.stackexchange.com/questions/7535/what-precautions-should-i-take-when-mixing-analog-audio-and-digital-on-the-same
• https://wiki.xtronics.com/index.php/Eeschema#Printing_to_a_web_viewable_file
• http://www.all-electric.com/schematic/simp_mix.htm
• http://sound.whsites.net/articles/audio-mixing.htm
• http://www.hobbyprojects.com/A/mixers.html
• https://www.maximintegrated.com/en/app-notes/index.mvp/id/1133
• https://books.google.com/books?id=rZDbnQ0siCYC&pg=PA65&lpg=PA65&dq=max6820+capacitor+value&source=bl&ots=sMOHEXxgaR&sig=d1sH1XYZMVvH4Y1nVS2bvKtejF0&hl=en&sa=X&ved=0ahUKEwic_NTY_e3PAhXBx4MKHRdlA-UQ6AEIRTAH#v=onepage&q=max6820%20capacitor%20value&f=false
• http://electronics.stackexchange.com/questions/5403/standard-pcb-trace-widths
• http://electronics.stackexchange.com/questions/185212/i2c-pcb-layout-considerations
• http://electronics.stackexchange.com/questions/39136/competing-pcb-crystal-layout-recommendations
• http://electronics.stackexchange.com/questions/41851/how-critical-is-the-layout-of-usb-data-lines-how-does-my-layout-look
• http://www.atmel.com/Images/Atmel-8128-Best-Practices-for-the-PCB-Layout-of-Oscillators_ApplicationNote_AVR186.pdf
• http://www.ti.com/lit/an/scaa082/scaa082.pdf
• http://electronics.stackexchange.com/questions/15135/decoupling-caps-pcb-layout/
• http://electronics.stackexchange.com/questions/117817/learning-pcb-layout-strategy
• http://electronics.stackexchange.com/questions/216410/pcb-layout-needs-improvement
• http://electronics.stackexchange.com/questions/28251/rules-and-guidelines-for-drawing-good-schematics
• http://electronics.stackexchange.com/questions/20180/pcb-layout-questions-for-mcu-breakout-board
• http://electronics.stackexchange.com/questions/19688/is-it-normal-to-have-a-rats-nest-of-vcc-gnd-traces-under-an-ic
• http://www.onmyphd.com/?p=pcb.design
• http://www.ti.com/lit/an/scaa048/scaa048.pdf
• http://www.hottconsultants.com/questions/mixed-signal_PCB_layout.html
• http://www.hottconsultants.com/questions/supplying_power_to_a_mixed-signal_PCB.html
• http://www.analog.com/en/analog-dialogue/articles/staying-well-grounded.html

Microphone references for future iterations of design

• http://electronics.stackexchange.com/questions/141499/5v-electret-microphone-to-pc-mute-switch-pop-help