PCB Design for Hothouse Project
0:15
Thought for a moment
You usually don’t need to know “old” by age. In this case, “old traces” means any routed copper trace that is currently causing errors after we resized/replaced the board.
Easiest way to identify them:
- Open the Review / Issues panel.
- Look for these issue types:
- Dangling Traces
- Floating Copper
- Overlapping Copper
- Airwires
- Click one issue, for example
Trace 147borTrace 321b. - Flux should highlight that trace on the PCB.
- That highlighted trace is one of the problem traces to unlock/delete.
- Repeat for each listed trace issue.
Do not delete:
- component footprints
- pads
- board outline
- schematic parts
- net labels
Do delete/unlock:
- highlighted copper routes/traces/vias associated with those review errors.
A shortcut: if there’s an option like delete all routing, rip up traces, or clear routed copper, use that. That is safer than trying to identify individual old traces one by one, because the schematic connections remain intact and the board will simply show airwires again for rerouting.
List trace issues
Rip-up guidance
Check USB2_D_P
Highlight DRC issues
Refine this doc
Ask about this doc
Hothouse Desktop Chain DSP — Project Specification
Product Summary
Hothouse is a desktop three-stage stereo DSP effects processor using three Electrosmith Daisy Seed modules. Audio flows in series:
Stereo In -> Unit 1 Filter/Gain -> Unit 2 Tensor -> Unit 3 Delay/Reverb -> Stereo Out
Each Daisy Seed runs independent firmware and exposes its own USB Micro-B connection for DFU flashing and USB MIDI.
Intended PCB Architecture
The supplied prompt requests four physical boards:
- Unit PCB A — Filter/Gain Daisy Seed controls and audio I/O interface
- Unit PCB B — Tensor Daisy Seed controls and internal audio chain
- Unit PCB C — Delay/Reverb Daisy Seed controls and audio output interface
- Power/Interconnect PCB — 9 V input, protection, 5 V regulator, USB panel jacks, and inter-unit stereo audio routing
Important implementation note: this Flux project currently represents one schematic/layout project. The cleanest execution path is to start with the shared power/interconnect PCB or one reusable unit PCB, then clone/fork for the remaining board variants as needed.
Enclosure and Mechanical Requirements
- Enclosure: Hammond 1455Q2201 or close 1455-series equivalent, about 220 mm x 120 mm x 51 mm.
- Unit PCB size: 90 mm x 70 mm, three boards side-by-side.
- Power/interconnect PCB size: 90 mm x 40 mm.
- Mounting holes: 4x M3, 3.2 mm diameter, copper-free keepout.
- Board edge keepout: 5 mm.
- Layer count: 2 layers, FR4, 1.6 mm, 1 oz copper.
- Signal trace minimum: 0.3 mm.
- Power trace minimum: 0.8 mm.
- Bottom copper should act as ground plane.
- Input: 9 V DC barrel jack, center-positive, 2.1 mm inner / 5.5 mm outer.
- Supply rating: 500 mA minimum at 9 V.
- Protection: 500 mA polyfuse on 9 V input.
- Reverse-polarity protection: 1N5817 Schottky diode in series before regulator.
- Regulator: LM2940CT-5.0 preferred over LM7805, TO-220.
- Regulator support capacitors requested: 10 uF electrolytic + 100 nF ceramic on input and output.
- 5 V bus powers all Daisy Seeds via VEXT.
- Per-unit bulk capacitance: 470 uF / 16 V on 5 V rail.
- Chassis coupling: PCB GND to chassis through 1 Mohm resistor in parallel with 10 nF capacitor.
Power Budget
- Estimated load: 150 mA per Daisy Seed at 5 V.
- Total 5 V load: 450 mA.
- 5 V output power: 2.25 W.
- Approximate 9 V input current ignoring regulator losses: 250 mA.
- Linear regulator dissipation at 9 V input: (9 V - 5 V) x 0.45 A = 1.8 W before diode/fuse losses.
- Thermal note: 1.8 W in TO-220 needs deliberate copper/heatsink area and may run hot in an enclosed aluminum case. A buck regulator is strongly recommended if thermal margin is poor, even though the source prompt calls for LM2940/LM7805.
Per-Unit Daisy Seed Mounting
- Daisy Seed module: 33 mm x 59.4 mm.
- Mounting: two 1x15 female headers, 2.54 mm pitch.
- Header row spacing: 27.94 mm center-to-center.
- VEXT powered from regulated 5 V.
- Daisy Seed 3V3 output used as reference for potentiometer top pins and switch logic.
- USB end must remain accessible or route to panel jack by short extension cable.
Per-Unit Controls
Each unit has:
- 6x Alpha 9 mm vertical B10K linear potentiometers.
- Pot layout: two rows of three; 19 mm horizontal spacing; 25 mm vertical row spacing.
- Pot wiring: top pin to Daisy Seed 3V3, bottom pin to GND, wiper to analog input.
- ADC filter: 100 nF from each wiper to GND.
- 3x SPDT ON-ON toggle switches.
- Preferred switch wiring: center to Daisy Seed GPIO, one outer to GND, other outer no-connect, using internal pull-up in firmware.
- Switch debounce/filter: 100 nF from GPIO to GND.
- 1x status LED per unit, preferably visible through panel. Alternative is to rely on Daisy Seed onboard LED/light pipe.
Daisy Seed Control Pin Assignments
Analog knobs:
- K1 -> A0, Seed pin 15
- K2 -> A1, Seed pin 16
- K3 -> A2, Seed pin 17
- K4 -> A3, Seed pin 18
- K5 -> A4, Seed pin 19
- K6 -> A5, Seed pin 20
Switches:
- SW1 -> D0, Seed pin 0
- SW2 -> D1, Seed pin 1
- SW3 -> D2, Seed pin 2
LED:
- Panel LED option: D13 -> 470 ohm resistor -> LED anode; LED cathode -> GND.
Audio Requirements
External input on Unit 1/right side panel:
- 2x Neutrik NJ3FP6C 1/4 inch TS mono jacks: IN L, IN R.
- Tip to Daisy Seed audio input through 4.7 uF / 16 V electrolytic DC-blocking capacitor.
- Sleeve to GND.
External output on Unit 3/left side panel:
- 2x Neutrik NJ3FP6C 1/4 inch TS mono jacks: OUT L, OUT R.
- Daisy Seed audio output to jack tip through 4.7 uF / 16 V electrolytic DC-blocking capacitor.
- Sleeve to GND.
Internal chain:
- Unit 1 OUT L/R -> Unit 2 IN L/R.
- Unit 2 OUT L/R -> Unit 3 IN L/R.
- Inter-unit wiring through JST-PH style connectors on the power/interconnect board.
- Each inter-unit signal line includes 4.7 uF / 16 V electrolytic DC-blocking capacitor.
USB and MIDI
- 3x USB Micro-B panel jacks on top panel, labeled USB 1, USB 2, USB 3.
- Each routes by short internal cable to the corresponding Daisy Seed USB Micro-B port.
- MIDI over USB, omni channel.
- CC 20-25: knobs 1-6.
- CC 26-28: switches 1-3.
- CC 29: bypass.
- CC 30: output level.
- Unit 3 responds to MIDI clock for tempo-synced delay.
Functional Identity by Unit
Unit 1 — Filter/Gain:
- Knobs: Filter, Resonance, Threshold, Ratio, Gain 1, Gain 2.
- Switches: Filter Q Wide/Peak, Compressor Optical/VCA, Drive Tape/Hard Clip.
Unit 2 — Tensor:
- Knobs: Speed, Pitch, Window, Feedback, Blend, Texture.
- Switches: Speed Continuous/Quantized, Transport Forward/Reverse, Gesture Smooth/Clock-slice.
Unit 3 — Delay/Reverb:
- Knobs: Delay Time, Delay Feedback, Reverb Size, Reverb Tone, D/R Balance, Wet Mix.
- Switches: Delay Tape/Ping-pong, Reverb Plate/Cloud, Mod Light/Wide.
Open Engineering Decisions Before Schematic Capture
- Which physical PCB should this Flux project implement first: reusable unit PCB, power/interconnect PCB, or a combined single-board prototype?
- Should I follow the requested linear regulator exactly, or upgrade to a buck regulator for lower heat? The 7805/LM2940 option dissipates roughly 1.8 W at full load.
- Should the panel LEDs be separate through-hole LEDs driven from D13, or should the Daisy Seed onboard LEDs be exposed with light pipes?
- Confirm the exact Electrosmith Daisy Seed pin names/part in the Flux library and whether its audio codec pins are represented as module pins.
- Confirm whether the audio jacks are mounted directly on unit PCBs or connected by panel wiring to board headers.
- Confirm whether separate AGND/DGND is truly desired on 2-layer audio boards; a continuous ground plane with careful partitioning may be safer than split planes if signal return paths cross the split.
Recommended Next Step
Start with the power/interconnect PCB if the goal is system integration and power safety. Start with one reusable unit PCB if the goal is the control/audio interface board that gets replicated three times.
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