Second Opto circuit in VR space on 3.0 PCB - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 04-29-2011, 10:35 AM   #1
Newb
Thread Starter
 
Join Date: Feb 2011
Location: Oxford UK
Posts: 39
Total Cats: 0
Default Second Opto circuit in VR space on 3.0 PCB

Hi folks

I've been busy and come up with a good way to install the second optoisolater needed for the CKP signal input on a Mk1, using the space that's free from not installing the VR circuit.

Instructions

1) Install the second 4n25 in the lower six pins of U7.
2) Jumper U7 pin 4 to pin 5
3) Jumper U7 pin 1 to pin 6
4) Install a 0.01 capacitor between U7 pin 6 and pin 5 or pin 4
5) Install a 470ohm resistor between the top hole of R44 and U7 pin 8
6) Install a 4k7ohm resistor between the left hole of R50 and U7 pin 8
7) Jumper the top hole of R52 to SPR1
8) Jumper VRout to JS10

Schematic

Name:  Opto-2input.jpg
Views: 5
Size:  39.6 KB



Please excuse the poor quality of the scan, but hopefully it's clear enough.

Nice and neat, and it saves you space in the proto area for other things.

Last edited by PeteNMA; 04-30-2011 at 03:45 PM.
PeteNMA is offline   Reply With Quote
Old 04-29-2011, 10:59 AM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

you dont NEED the second opto.

looks similar to how i ended up doing it.





its a mess up under:

Braineack is offline   Reply With Quote
Old 04-29-2011, 11:18 AM   #3
Newb
Thread Starter
 
Join Date: Feb 2011
Location: Oxford UK
Posts: 39
Total Cats: 0
Default

I know you don't need the second one, but I've had several people tell me that it's worth putting it in as a belt and braces solution.

It's that mess on the proto area that I'm trying to avoid, I figure that the space is there, might as well use it.
PeteNMA is offline   Reply With Quote
Old 04-29-2011, 11:22 AM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

the opto circuit I'm running takes up little space...

I have two additional p2n222s for the Joe's spark output mod, and a input relay for my a/c switch, and the opto circuit, and a 100ohm resistor for the boost control mod.


let me map out what i did.
Braineack is offline   Reply With Quote
Old 04-29-2011, 11:44 AM   #5
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 198
Default

Quote:
Originally Posted by Braineack View Post
you dont NEED the second opto.
EVERY single NA I've built a Megasquirt 2 for, ALWAYS had problems with ramdom tach dropout without the second opto.

Yes, you ABSOLUTELY NEED the 2nd opto circuit for Megasquirt 2. If you randomly lose sync, this is your solution.
Reverant is offline   Reply With Quote
Old 04-29-2011, 11:50 AM   #6
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

weird. never had the issue.
Braineack is offline   Reply With Quote
Old 04-29-2011, 11:58 AM   #7
Newb
Thread Starter
 
Join Date: Feb 2011
Location: Oxford UK
Posts: 39
Total Cats: 0
Default

I'm just a neat freak when it comes to electronics, my experience is that if you make it neater then it's more likely to work first time and easier to troubleshoot if you need to.
PeteNMA is offline   Reply With Quote
Old 04-29-2011, 12:03 PM   #8
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

no doubt. I did that spur of the moment, beforehand it looked great.
Braineack is offline   Reply With Quote
Old 04-29-2011, 05:32 PM   #9
Newb
Thread Starter
 
Join Date: Feb 2011
Location: Oxford UK
Posts: 39
Total Cats: 0
Default



Here's a shot of how far I've got. I've also just realised that the 0.01uF capacitor can be fitted in place of R55.
PeteNMA is offline   Reply With Quote
Old 04-29-2011, 10:31 PM   #10
Junior Member
 
Join Date: Sep 2010
Location: SFL
Posts: 376
Total Cats: 3
Default

interesting use of the spare space
MD323 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Toyota Pickup Engine Swap B.S. Monk Build Threads 24 12-11-2016 03:21 PM
Prepping my '95 for track asmasm Build Threads 82 05-26-2016 05:37 PM
CAS weirdness Asx MEGAsquirt 5 12-15-2015 12:14 PM
Did I fry my daughterboard? wred MEGAsquirt 20 10-16-2015 02:26 AM
New CKEditor Disabled To Prepare for Update IB Nolan Front Desk 3 09-23-2015 09:32 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:50 AM.