# Stripboard Layout Suggestion

This is a practical suggested layout for moving the current bench wiring onto stripboard. It is not a PCB netlist. It is a placement and routing plan intended to reduce wiring chaos while keeping the high-voltage VFD side separated from the low-voltage logic side.

Use this together with:

- [wiring.md](/home/adebaumann/development/arduino_gauge_controller/wiring.md:1)
- [Rewire_checklist.md](/home/adebaumann/development/arduino_gauge_controller/Rewire_checklist.md:1)

## Design Goals

- keep `5V logic` on one side
- keep `VFD high voltage` on the opposite side
- keep the `HV5812P` between those two domains
- bring all off-board wiring to clearly labeled edge connectors
- avoid crossing the gauge step/dir wiring through the VFD area
- make debugging possible with scope probes and a meter

## Recommended Board Strategy

Use one main stripboard for:

- Arduino Mega interface headers
- HV5812P and its support wiring
- connectors for the VFD tube
- connectors for the three gauge drivers
- connector for the WS2812 strip
- connector for the ESP32 UART link

Do not mount the Arduino Mega itself onto stripboard. Use pin headers or screw terminals so the Mega remains removable.

If possible, also do not mount the ESP32 directly unless you already have a reliable carrier board for it.

## Suggested Physical Zoning

Arrange the board in four zones from left to right:

1. `Mega / ESP32 low-voltage I/O zone`
2. `Gauge / LED connector zone`
3. `HV5812P driver zone`
4. `VFD high-voltage and tube connector zone`

That gives you a left-to-right flow like this:

```text
[ Mega / ESP32 ] [ Gauge + LED connectors ] [ HV5812P ] [ VFD + HV connectors ]
```

This is better than putting the HV5812 at the edge near the Mega, because the HV5812 is the boundary device between logic and high voltage.

## Board Orientation

Assume the stripboard copper tracks run horizontally.

Recommended use:

- horizontal tracks for local distribution
- vertical jumps made with insulated wire links

Cut tracks aggressively around the HV5812P so it does not accidentally join unrelated nets through the copper strips.

## Left Side: Mega / ESP32 Interface

Place a row of labeled pin headers or screw terminals for the signals coming from the Mega:

- `5V`
- `GND`
- `D22`
- `D46`
- `D47`
- `D48`
- `D49`
- `D50`
- `D51`
- `D52`
- `D53`
- `RX1`
- `TX1`

Place a second small header for the ESP32:

- `ESP32 TX`
- `ESP32 RX`
- `ESP32 GND`

Keep these headers near one board edge so you can unplug and rework them easily.

## Middle-Left: Gauge / LED Connectors

Place four connector groups near the Mega interface side:

1. `Gauge 0`
   - `DIR`
   - `STEP`
   - `GND`
2. `Gauge 1`
   - `DIR`
   - `STEP`
   - `GND`
3. `Gauge 2`
   - `DIR`
   - `STEP`
   - `GND`
4. `WS2812`
   - `DIN`
   - `5V`
   - `GND`

This keeps all low-voltage off-board connections together.

## Center: HV5812P Zone

Mount the `HV5812P` roughly in the center-right of the board.

Reason:

- logic-side control pins can approach from the left
- high-voltage outputs can leave to the right toward the VFD connector

Around the HV5812P:

- isolate each used pin with track cuts as needed
- keep short local links for `DATA`, `CLOCK`, `STROBE`, `BLANKING`
- keep `VDD` decoupling physically close to the chip

Recommended support parts close to the HV5812P:

- `100 nF` ceramic decoupling capacitor between `VDD` and `GND`
- one larger bulk capacitor on the `5V` rail nearby, for example `10 uF` to `47 uF`

If you already use any datasheet-recommended support parts for the HV side, place them in this same zone.

## Right Side: VFD Connector Zone

Put the VFD connectors on the far right side of the board, physically separated from the Mega headers.

Provide terminals or headers for:

- `HVOut1` -> `A`
- `HVOut2` -> `B`
- `HVOut3` -> `C`
- `HVOut4` -> `D`
- `HVOut5` -> `E`
- `HVOut6` -> `F`
- `HVOut7` -> `G`
- `HVOut8` -> `DP`
- `HVOut9` -> `BELL`
- `HVOut10` -> `GRID1`
- `HVOut11` -> `GRID2`
- `HVOut12` -> `GRID3`
- `HVOut13` -> `GRID4`
- `HVOut14` -> `GRID_IND`

Also provide separate terminals for:

- `VPP`
- `GND`
- filament connections

Keep the filament connections away from the logic-side headers.

## Suggested Power Buses

Use distinct buses and label them clearly:

- `5V LOGIC`
- `GND`
- `VPP`

Recommended physical arrangement:

- `5V` bus along the top-left area only
- `GND` bus available across the board
- `VPP` bus only on the far-right HV area

Do not run a long exposed `VPP` strip through the entire board. Keep the high-voltage distribution short and local to the HV5812 and VFD connector side.

## Suggested Routing

### Mega to HV5812

Route these as short direct runs:

- `D46` -> `DATA`
- `D47` -> `CLOCK`
- `D48` -> `STROBE`
- `D49` -> `BLANKING`

These should pass from the left interface zone into the HV5812 zone without crossing the VPP area.

### Mega to Gauges

Route these directly to the gauge connector blocks:

- `D50` -> gauge 0 `DIR`
- `D51` -> gauge 0 `STEP`
- `D8` and `D9`
  If you are bringing these through the stripboard too, add them to the Mega header group and route them directly to gauge 1.
- `D52` -> gauge 2 `DIR`
- `D53` -> gauge 2 `STEP`

If `D8` and `D9` come from separate fly wires to the stripboard, keep them in the same low-voltage connector area as the rest of the gauge lines.

### Mega to WS2812

Route:

- `D22` -> main backlight/status strip `DIN`
- `D36` -> indicator strip `DIN`
- `5V` -> both strip `5V` inputs
- `GND` -> both strip `GND` inputs

Keep the LED connector in the low-voltage area.

### ESP32 to Mega

If the stripboard is acting as the interconnect backplane:

- `ESP32 TX` -> `Mega RX1`
- `ESP32 RX` -> `Mega TX1`
- `ESP32 GND` -> `GND`

## Track Cuts and Links

Recommended stripboard discipline:

- every IC pin should be visually checked for unintended strip continuity
- cut under or near pins wherever two adjacent pins must not share the strip
- use insulated jumpers for crossings instead of relying on long exposed component leads
- use a continuity meter after every 5-10 wires added

For the HV5812P specifically:

- assume most adjacent pins must not be left on the same uninterrupted strip
- cut first, then add intentional links

## Physical Separation Rules

Keep these separations:

- logic and UART wiring away from `VPP`
- VFD output traces away from ESP32 and Mega headers
- gauge step/dir traces away from VFD high-voltage outputs where possible

If you can, leave at least one empty strip gap between low-voltage and high-voltage routing regions, and more where practical.

## Labeling

Label the board directly with marker or printed tape.

At minimum label:

- `5V`
- `GND`
- `VPP`
- `DIN`
- `CLK`
- `STR`
- `BLK`
- `G0 DIR`
- `G0 STEP`
- `G1 DIR`
- `G1 STEP`
- `G2 DIR`
- `G2 STEP`
- `LED DIN`
- `RX1`
- `TX1`
- `A B C D E F G DP BELL G1 G2 G3 G4 GI`

This matters more than aesthetics. A labeled board is much easier to repair later.

## Practical Build Order

1. Place and mark the four physical zones.
2. Mount the low-voltage connector headers.
3. Mount the HV5812P.
4. Cut all required strips around the HV5812P before adding wires.
5. Add `GND` and `5V` low-voltage distribution.
6. Add Mega-to-HV5812 logic lines.
7. Add gauge and LED connector routing.
8. Add `VPP` and the VFD output connector routing.
9. Add the VFD filament connector.
10. Verify continuity and shorts before any power is applied.

## Recommended First Continuity Checks

Before power:

- `5V` is not shorted to `GND`
- `VPP` is not shorted to `GND`
- `VPP` is not shorted to `5V`
- `D46/D47/D48/D49` are only connected to the intended HV5812 pins
- `D50/D51/D52/D53/D8/D9` are only connected to the intended gauge connectors
- `D22` only goes to the WS2812 connector
- `RX1/TX1` are not swapped at the stripboard labels

## Suggested Board Size

For comfort rather than minimum size, use a board large enough to avoid crowding:

- roughly `100 x 160 mm` or larger if you want good service access

Smaller is possible, but with mixed logic, UART, gauge control, LEDs, and VFD high voltage, cramped stripboard becomes harder to debug than a rat's nest.

## Recommendation

If you want the cleanest result:

- use the stripboard only as an interconnect backplane
- keep the Mega, ESP32, and possibly the gauge drivers off-board on removable connectors
- keep the HV5812 and VFD connector area on the stripboard itself

That gives you most of the neatness benefit without forcing the whole system into one dense board.

## ASCII Top View

This is a suggested top-view arrangement, not a strict scale drawing.

```text
Top edge

+--------------------------------------------------------------------------------------------------+
| [Mega Header Block]                [Gauge / LED Connectors]          [HV5812P Zone] [VFD Zone] |
|                                                                                                  |
|  5V  GND  D22  D46  D47  D48  D49  D50  D51  D52  D53  RX1  TX1                                 |
|  o    o    o    o    o    o    o    o    o    o    o    o    o                                  |
|                                                                                                  |
|  [ESP32 Header]                                                                                  |
|  TX   RX   GND                                                                                   |
|  o    o    o                                                                                     |
|                                                                                                  |
|                                [Gauge 0]   [Gauge 1]   [Gauge 2]   [WS2812]                     |
|                                DIR STEP G  DIR STEP G  DIR STEP G  DIN 5V G                     |
|                                 o   o   o   o   o   o   o   o   o   o  o  o                     |
|                                                                                                  |
|                                                            +----------------------+              |
|                                                            |      HV5812P         |              |
|                                                            |                      |              |
|  5V LOGIC BUS ============================================>| VDD                  |              |
|  GND BUS      ============================================>| GND                  |==============|
|                                                            | DIN  CLK STR BLK     |              |
|                                                            |  ^    ^   ^   ^      |              |
|                                                            +--|----|---|---|------+              |
|                                                               |    |   |   |                     |
|                                                               |    |   |   +---- D49             |
|                                                               |    |   +-------- D48             |
|                                                               |    +------------ D47             |
|                                                               +----------------- D46             |
|                                                                                                  |
|                                                                               VPP terminal       |
|                                                                               o                  |
|                                                                               |                  |
|  HV AREA                                                                     |                  |
|  kept to right side only                                                     |                  |
|                                                                               v                  |
|                                                         A  B  C  D  E  F  G  DP BELL G1 G2 G3 G4 GI
|                                                         o  o  o  o  o  o  o  o   o    o  o  o  o  o
|                                                         [VFD output connector block]             |
|                                                                                                  |
|                                                         FIL_A  FIL_B  GND/HVRET                  |
|                                                          o      o       o                        |
|                                                         [filament / HV return terminals]         |
|                                                                                                  |
+--------------------------------------------------------------------------------------------------+

Bottom edge
```

## Reading The Sketch

- left side:
  all low-voltage headers from the Mega and ESP32
- center-left:
  gauge and LED connector blocks
- center-right:
  HV5812P
- far right:
  VFD outputs, filament, and `VPP`

This keeps the dangerous and noisy wiring concentrated on one side of the board.

## Suggested Copper-Strip Use

If your strips run horizontally:

- use upper strips for low-voltage headers and distribution
- use middle strips for gauge and LED routing
- isolate the HV5812P pin rows heavily with track cuts
- use lower-right strips only for the VFD output area and `VPP`

## Suggested Connector Edge Placement

If you want the board to be easy to service:

- put Mega and ESP32 headers on the left edge
- put gauge and LED connectors on the bottom edge
- put VFD and high-voltage terminals on the right edge

That way:

- low-voltage control cables enter from the left and bottom
- high-voltage VFD wires leave only on the right

## Minimum Clearance Advice

On stripboard, do not pack the `VPP` and VFD output terminals tightly against the low-voltage headers.

Practical suggestion:

- leave at least several empty holes / one empty strip region between the HV5812 logic-side routing and the `VPP` / VFD connector zone
- if you have room, leave more than that

More separation is better than a dense layout here.