Repo for designing a custom pcb that controlls the electrical components of an IHC-Tractor.

Links
Overview
Open Schematic and Layout
Connector Pin-assignment
- New Connectors
- Old Connectors
I/O List
- Switches
- Relays
Instructions (milling process)
Notes for next version (pcb design)
Notes for next pcb (milling)
- CNC-Control (WinPC-NC)
  - Parameters
  - Occurred problems
- G-code generation (pcb2gcode)
  - Notes for next time
  - Gerber export (kicad)

Overview

Schematic

pcb-ihc_schem_v4-milled-v1.1.pdf

PCB-layout

Open Schematic and Layout

Install kicad and open /kicad/pcb-ihc_kicad.kicad_pro

For quickly viewing the current schematic and layout without installing kicad see exported files in kicad/export or complete documentation at https://pfusch.zone

Connector Pin-assignment

New Connectors

See plan in firmware repo: https://github.com/Jonny999999/ihc-control_fw/blob/master/connection-plan.pdf

Old Connectors

2 Pole connector 6mm2:

1: Starter motor (9)
2: Glowplug

6 Pole PC (3)

1: empty
2: Front light right, left (top right)
2a: Switch brakelight LS 1/2
3: Horn 1/2
3a Switch brakelight LS 2/2
4: Light left AL, right AR (bottom right)

6 Pole PB (2)

1: (20) Starter motor (relay) (top left)
2: (22) Fuel sensord
3: (24) Horn 2/2
4: (26) Oil pressure (switch to gnd)
5: (28) Temperature sensor
6: (30) Voltage regulator alternator (?)

6 Pole PA (1)

1: (31,32) FD sidelight -> trailer connector
2: (37) LB LB Light left -> trailer connector
3: (90) Side light BR
4: (88) Side light BL
5: (43, 42) FA -> trailer connector
6: (48) LA light left -> trailer connector

I/O List

List of required I/O pins for planning the board

Switches

Switch to GND (pullup input)

S_Warning Lights
S_TurnLeft toggle
S_TurnRight toggle
S_HighBeam momentary
S_Warning Lights toggle
S_Horn

Switch to 12V (pulldown input)

S_ParkingLight
S_LowBeam
S_Brake

Notes

S_worklight !!! no input left?!

Relays

K_BlinkLeft
K_BlinkRight
K_ParkingLight
K_LowBeam
K_HighBeam
K_Horn

Instructions (milling process)

Machine used: Stepcraft 420

Step 1: export files

Kicad: Export/plot pcb to gerber files Note: Also export User1 layer (includes text for engraving)
Kicad: Generate drill file

back=./in/pcb-ihc_kicad-B_Cu.gbr
front=./in/pcb-ihc_kicad-F_Cu.gbr
outline=./in/pcb-ihc_kicad-Edge_Cuts.gbr
drill=./in/pcb-ihc_kicad-PTH.drl
see config file: pcb2gcode/millproject

Step 2: generate gcode (holes, traces, outline)

run pcb2gcode: ihc-control_pcb/pcb2gcode> pcb2gcode
will use millproject file for parameters as default config

Step 3: generate gcode (engraving text)

Kicad: moved text to be engraved into pcb on separate layer (User1)
Also export/plot User1 layer with other gerber files
Use separate millproject_text parameter file with pcb2gcode pcb2gcode --config millproject_text NOTE: also include outline and maybe front in that millproject, even though that output is not used. It is necessary that the origin fits, otherwise there will be an offset!
The trick was to use a negative offest (almost half the line width) to get more or less clean characters
Generates pcb2gcode/out/text/back.ngc Note: check if there is an offset/scaling issue to other files (back, drill). last time text got engraved into traces even though it matched on the other side

Step 4: mill outline

Was not necessary in this case because size already matched

Step 5: post processing

Slightly smooth copper layer of pcb using grinding wool
Drill holes for big 4mm2 2-pin terminals to 1.5mm if drilled with just 1mm on cnc

Notes for next version (pcb design)

Add resistor and diode for slowly charging the input capacitor (limit charging current)
Add diode and/or jumper for isp programmer. Noticed that current is flowing from board 5v to programmer (input resistor got hot - only when programme connected) (alternatively jumper on programmer can be used for this...)
ADD FUSES
- Add fuse for 12v supply to 5v regulator
- Fuses for mosfets?
- Fuses for relay?
Add mounting holes / at least make some space for third hole
Slightly smaller size for easier cnc-milling

Notes for next pcb milling

CNC-Control (WinPC-NC)

Parameters

WinPC-NC has weird default z coorinates direction => Z coordinates have to be inverted (!!!!!) (otherwise will crash) -> parameters -> dateiformat -> z-koordinaten invertieren
Change units to mm/min instead of default mm/s

Occurred problems

Problem Stepper not moving, only producing noise, but winpc-nc actually thinks that it moved coordinates - especially happened for Z-Axis
- Solution 1: remove top section of gcode (simple G1 commands worked - see gcode generated with estlcam that is compatible)
- Solution 2: switch from windows in Virtualbox to native windows

G-code generation (pcb2gcode)

notes for next time:

TODO: merge this section with milling instructions?

Text engraving: slightly reduce Z depth
Zero Z-axis on multiple places: At 2 edges pcb material was apparently lower, thus only scratched the surface -> had to mill again
Zero-XY NOT at file origin! (the offset is caused by outline cutter diameter)
- 1. Load outline gcode, zero x,y next to border (note offset)
- 1. Confirm with moving on other side of pcb
Make screenshot of absolute coordinates of origin (in case of accidential shift / position loss)
Check position before drilling holes
Fixing the pcb: Screws around the pcb are probably enough (check bend)
When generating gcode for text separately, also include at least outline, otherwise there is an offset (origin makes no sense)

Gerber export (kicad)

design pcb slightly smaller for more tolerance...
define custom origin => tried this, setting "drill/place file origin" and tick the checkbox at plot, but had no effect to pcb2gcode in any way
check if origin is the same in every gerber/gcode file (verify with gcode viewer?)

jonny999999 / ihc-control_pcb Goto Github PK

ihc-control_pcb's Introduction

TOC

Links