This PCB is intended to be used in conjunction with a separate microcontroller module to create a basic engine management system. It has a simple power supply and enough general purpose I/O to get started. Basically any microcontroller and software combo can be used but it is particulary designed to be used with the open-source FreeEMS project.
Its ideal for people who wants to experiment and learn about the world of engine management.
The project is done with CadSoft Eagle version 6.x and is kept within the freeware limitations.
http://www.cadsoftusa.com/download-eagle/freeware/
- 2-Layer PCB
- Size is about 10x10cm (fits in a euro case)
- 5V LDO regulated power supply with VDR protection
- 2 Polyfuse protected 5V reference voltage outputs
- 4 auto-protected injector outputs (high impedance only)
- 2 auto-protected accessory outputs
- 4 mosfet drivers for ignition amplifiers (5V or 12V)
- 4 protected A/D inputs
- 4 protected temperature inputs (can be used as normal A/D)
- 2 protected on/off switch inputs
- 2 ground loop monitor inputs
- CEL LED and run/load switch for FreeEMS
One thing to point out is that at this stage the board DOES NOT have VR/Hall sensor inputs. As these sensors are mandatory to operate an EMS there are pin headers/DIP8 socket and places for shunt resistors (used with VR) to be used with a separate BrickRPM VR conditioner board. More info at: http://brickems.com/brickrpm/
The schematic and board file both have a placeholder for git commit id. This is used with the git clean/smudge filter. The .gitattributes file is included with the project but it only defines the files to be filtered with a filter called "hasher". You can use this feature by adding this into your .git/config file:
[filter "hasher"]
smudge = sed \"s/GIT %GIT_COMMIT_ID%/GIT `git rev-parse --verify HEAD --short`/\"
clean = sed \"s/GIT [0-9a-z]\\{7\\}/GIT %GIT_COMMIT_ID%/\"
As you can see this is OS specific and works straight in Linux and OSX.
The filter has one downside which is the need to make an extra deletion and checkout for the id to be "smudged". For example if you clone this project the git placeholder don't have the current id. You need to delete the files and checkout them for the id to be updated:
$ rm onionboard.sch onionboard.brd
$ git checkout onionboard.sch onionboard.brd
The project uses a separate Molex connector library I found here: https://code.google.com/p/rdubniewski-test/source/browse/trunk/eagle.lib/con-molex-5569.lbr It's also included in the libs directory.
If you decide to home etch this pcb I recommend to make the vias larger (the copper area) before doing so. This way its easier to drill them and solder the connecting wire.
Heres a good tip for home made vias: http://www.youritronics.com/double-layer-pcb-home-made-vias/
- Get more testing done and lots of driving/racing.
- Possibly put a dual VR conditioner on board (MAX992x based)
- Also one H-bridge driver would be ideal
- TA Adapt9S12XDP512 - http://www.technologicalarts.ca/shop/store/details/453/11/microcontrollers/adapt9s12xdp512m2-xgate-mcu-module,-full-configuration.html
- ElMicro CardS12 - http://elmicro.com/en/cards12.html
- WayEngineer MC9S12XDP512-core - http://www.wayengineer.com/index.php?main_page=product_info&products_id=281