readme.md
VX Dash

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What is it ?

VX Dash is an attempt at proposing a modular, cheap and entirely open-source digital instrument cluster for the Vauxhall VX220 ( also known as the Opel Speedster ). 
It is based on an ESP32 MCU coupled over Serial with a Nextion screen and an inexpertly designed vehicle interface PCB.

What can it do ?

As this project is not yet in the prototype phase, the current base capabilities targeted are very similar to the original cluster :
 - Full coverage of all the original Active Hi and Active Low inputs in the VX instrument clusters ( MIL light, Parking brake light, indicator lights ... )
 - Fuel level display
 - Engine coolant temperature display 
 - RPM and Speed display

Some additional functionalities are planned :
 - Four 5V "ECU" sensor voltage inputs for things such as oil pressure sensors, MAP sensors, IAT/boost sensors...
 - Four additional "VDO-style" analog resistive inputs, for "low impedance" voltage divider sensors, such as the ubiquitous VDO oil pressure and temperature sensors (typically 0-250Ohm)
 - One "High Resistance" analog resistive input, for higher impedance sensors (typically 0-2K)
 - Modular design to allow some changes between the analog resistive inputs (as in less low-R and more high-R inputs) with simple soldering
 - User-personalizable sensor curves via simple code pages in Arduino IDE
 - Additional free pins can be used and reassigned for variants with CAN interfaces for other vehicles
 ## What makes it tick ?
 Currently the hardware design (under CERN OHL v2 Strongly Reciprocal license) features the following :
 - Opto-isolated readouts of the Active Hi and Active Low cluster inputs (SFH617 optos)
 - Cheap and easily flashable EPS32 dev kit C main MCU
 - TVS diode protection for the 12V input, as well as a Schottky barrier for accidental over voltages
 - 12V -> 5V power conversion stage built around the AP63200WU-7 converter, with a max 2A output
 - 5V -> 3V3 power conversion stage built around the MP2322GQH, mimicking the power stages of the amazing Arduino Giga Wifi
 - Speed and RPM pulses amplification and normalisation with an old-school C4050 non-inverting hex buffer CMOS
 - Multiplexed non-critical binary inputs (Oil alarm, airbag light, ABS light, Ignition signal, Full beams light, Low coolant alarm, Brakes alarm, Alternator light, Parking Brake light, Immobilizer and Door light through a C4067 MUX
 - JAE MX34036UF2 36 pin connector (unfortunately not native directly with the original harness, but adapters can be made
 - Backfeed protection on the analog resistive sensor inputs
 - ESD protection on the voltage sensor inputs
 - Regulated 5V output to feed 5V sensors
 - 3 to 4 ( in the current configuration ) direct interrupts from the binary inputs into the MCU for fast response.
 - Odometer and trip distance saved in the flash memory of the MCU
 - Serial communication towards a ]]>Nextion "Intelligent" 7in display (NX8048P070)]]>, with free user-customizable interface sets
 - Not-yet designed, 3D printable and wrappable mechanical interface that should fit under the original instruments binnacle

What is the timeline ?

Currently, this is the status of the project :

A-sample


[ ] Preliminary circuit schematic for default variant (A-sample)
[ ] First PCB packaging
[ ] Test of coolant temperature input readability
[ ] Test of fuel level sensor
[ ] Test of analog resistive sensor inputs
[ ] Test of 5V sensor inputs
[ ] Test of RPM pulse counter
[ ] Test of Speed pulse counter
[ ] Test of input muxing
[ ] Preliminary screen HMI publication
[ ] Arduino code first draft with only signal acquisition architecture (no odometer, no trip) and screen interface variables
[ ] Implementation of sensor interpolation tables
[ ] Publication of current consumption tables per functional modules
### B-sample
[ ] Revision of power circuit
[ ] Revision of fusing
[ ] Revision of MCU input attributions
[ ] Possible revision of MUXing strategy and "on-demand" MUXing on input change (OR CMOS needed)
[ ] Revision of practical main connector pinout and I/O attributions (more V sensors, less R sensors, more direct MCU alarm lines ?)
[ ] Implementation of Screen set-up pages
[ ] Implementation of odometer and trip functions including flash saving
[ ] PCB re-packaging
[ ] Space-constrained enclosure design release
[ ] Function-to-core splitting of the sensor detection loops and write-to-screen loops
### C-sample
[ ] Hopefully just bug-fixing ? LOL
[ ] Enclosure refinements
[ ] Ultimate schematic changes
[ ] HMI refinements
[ ] PCB DFM iterations ( probably with PCBWay SMT services )
[ ] ??????
[ ] Enjoy