CDI-2012

Copyright 2012 Jake Stewart

Contact email: jakestew{at}mail{dot}com

License: This code is free for personal and limited commercial use. You may use and modify it as you see fit as long as you do not sell the code or any derivative work, or any product containing the above, without written permission. If you would like to use this in a commercial product please contact me for affordable licensing.

Unless you somehow consider your ignition curve and settings to be confidential secrets, please send me off a copy of the source, compiled hex, and spreadsheet whenever you find a good running/starting combination.  I'll collect these and make them available for people who want premade hex files or ignition curves.  I ask for the spreadsheet since the way I did the excel sheet I don't think it will be easy to paste the table from the source back into the spreadsheet.

Description: Timer1 is used to time the revolutions. Time base is the internal RC oscillator (8MHz). Timer1 compare mode is used to time the spark delay. Delay is loaded from the DegDelay[] table. Rev times larger than the table are calculated on the fly.

Joining the project: If you can help out please send me an email or join in the discussion at RCU.  We need electronics people to help with board/electronics design and putting schematics into Eagle, programmers to help work on the code, motor heads to help tell us what to do with the engines, writers to help with documentation, and webpage designers to help with the website (obviously).  Many people have put a lot of time into this project and it already works very well, but there are a lot of things left to be done before it's ready for the masses.

Credits... Special thanks to:

• John (gr8flyer55), for helping me get started with the project and providing CDI hardware for testing. 
• Ray Richter (Nav_Aids), for fixing bugs in the spreadsheets and a lot of other help.
• Nyemi, for writing the assembly version and testing out new ideas.
• jpanhalt, for helping with processor selection and general advice.
• lovefool, for reviewing the code and catching bugs.
• COM, for testing code and moral support.
• Rob (Gompy), for his advice and lending his many years of experience with engines and ignition systems to the project.
• Adrian, for helping me with hardware and general advice.
• Bluejets, for working on the hardware and electronics.

This project has been ongoing for at least the past several years. The vast majority of information on this project is contained in threads on rcgroups.com and rcuniverse.com. It's also the best place to ask questions and get help with the project.

Link to the new RCG discussion thread
Link to the OLD RCU discussion thread

Note: We switched from RCuniverse to RCgroups because of a number of server problems, image posting/uploading, and file posting problems there. RCgroups is a much better forum for us, and has a special forum dedicated to "DIY Electronics". Following the switch, a number of my posts were censored and/or deleted from RCuniverse, especially any mention of the switch or reasons for the switch. Personally, I will not tollerate censorship and heavy-handed moderation, and I suggest that you don't either. I'll try to occasionally check back there to avoid leaving anyone behind and point new people to the new thread location, but for the most part I'm boycotting RCuniverse.

Features...

• Runs at 8 MHz
• Completely interrupt driven
• Uses the 16-bit timer to time from the top end of around 15K RPM all the way down to about 916 RPM.
• Uses a 256 point, 16-bit table for timing
• The timer provides 1 uS resolution, giving 256 uS resolution on the high 8-bits and using rounding on the 8 low bits to provide a max RPM error of 128 uS. (128 millionths of a second)
• Using the high 8 bits of the timer naturally divides the uS per rev by 256. (then rounds with the high bit of the low 8)
• This works great for using Digi-Degrees (1= 360/256 = 1.4 degrees), which uses very little math on the PIC
• Calculated time delay for 120-915 RPM, under 2 RPS the engine is assumed to have died.
• Start mode for timing the first spark using estimated RPM and desired advance
• Special MSD setting just for starting
• Spreadsheet for creating tables and calculating user settings
• Three modes: Start mode, table mode (916-16K RPM), and on-the-fly calculation mode (120-915 RPM)
• Ability to save and load curves in the spreadsheet!
• Back-calculates the table values to double check settings
• Two selectable sets of settings and curves! Switch easily between them for testing.
• Digital kill switch.
• MSD features included, able to deliver multiple sparks per revolution.

Downloads...

Releases... (Use with the new spreadsheet versions below!)
CDI-2012_v1.0.zip  This file contains the Excel spreadsheet for generating the advance curves and project files for MPLAB X. The Excel sheet also contains the code for both 12F683 and 12F1840 processors.

CDI-2012_v1.0_B.xlsm  This is the Excel spreadsheet for Rob's (Gompy) version B timer board. Pull-ups are turned off for the switches and the polarities are reversed. Otherwise it's the same code. If you want the MPLAB project files and instructions download the above version and just remember to use this spreadsheet.

New Spreadsheet Versions!
A big thanks goes out to Ray Richter (Nav_Aids) for creating these versions!
Ray created these versions to fix a number of bugs in my spreadsheets. The v1.0 spreadsheets work great for me, running Excel 2007 on Windows XP SP3. However, it seems that several bugs crop up when using different Excel versions, and/or OS versions, and/or VB runtimes, and/or .Net framework versions. I have no way to test all these configurations, and I certainly can't fix all of Micro$oft's bugs, so Ray's mastery of VBA and Excel macros, and knowledge of the many version compatibility problems, have really helped the project. All future spreadsheets will be based off of these.

CDI-2012_v1.0-F1.1.xlsm  - This is the Excel spreadsheet for John's (gr8flyer55) timer board. Pull-ups are on for the switches and grounding the switch pin activates them.

CDI-2012_v1.0_B-F1.1.xlsm  - This is the Excel spreadsheet for Rob's (Gompy) version B timer board. Pull-ups are turned off for the switches and the polarities are reversed.

Important Note!!! The "kill switch" is just a handy feature. Do NOT rely on this as your only engine kill method! The current hardware may generate one spark on power up, and one spark on power down (even several minutes AFTER power down). ALWAYS have another method to kill the engine and NEVER allow any part of your body anywhere near the prop or engine without a reliable hardware/physical method of making sure the engine doesn't fire. If you don't have another switch, just pull the plug wire first!

I publish this open source software as an excercise of my right to free speech. Open source software is constitutionally protected free speech. I have NO liability for damages or injury resulting from how YOU decide to use this software!

There is no password on the file. All you have to do is go to...
- "Home -> Format -> UnProtect Sheet" to unprotect the sheet. You have to do this to each sheet you want to change.
- "Home -> Format -> Hide & Unhide -> Unhide Sheet" will let you unhide the hidden sheets.
- Ctrl-F1 will switch the ribbon between normal and auto-hide modes.
- Click "View -> Headings/Formula bar" to make headings and formula bar show back up.

Notice: This code works fine in the simulator, and will throw sparks when programmed on the chip in the actual circuit. John has even tested the code on a real engine. But, I take no responsibility for any damage caused. It is your responsibility to ensure that you are using proper settings for your engine and that you test the functioning of the CDI and program BEFORE you use it on an engine.