Notices
MEGAsquirt A place to collectively sort out this megasquirt gizmo

EE's: help me with this TPS circuit

Old Jan 22, 2009 | 02:20 AM
  #21  
JustinHoMi's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 273
Total Cats: 1
From: Hillsborough, NC
Default

Based on what Joe said in another thread, I think they're both pullups. I honestly don't know enough about electronics to be able to answer the question decisively though. I can tell you that before I developed this circuit, I ran 1K resistors from 5v to each tps output, and measured 0-5v on 1N, and 5-0v on 2L.

I do hope there is a simpler circuit! I've done some embedded programming in the past, but I've never had to deal with anything more than resistors and voltage regulators. It was fun learning to build that circuit, but I have a long ways to go....

The off/half/full is like you said... to tell when throttle is closed, partial, and WOT. I'm running custom code with MAFdot AE (AE based on the rate of change of MAF). Due to how jumpy the MAF signal is, I have to run a fairly high threshold, and consequently AE doesn't work on small changes of the throttle. So, I modified the code so that AE only turns on when the throttle is pressed (partially).

Additionally, I'd like the option of going into open loop when the partial is fully pressed. I'll also have more flexibility when it comes to some of the other features that use the TPS signal, such as idle control, idle advance, overrun, launch control, etc.
Old Jan 22, 2009 | 05:14 AM
  #22  
smifta's Avatar
Newb
 
Joined: Sep 2007
Posts: 13
Total Cats: 0
Default

Would it be easier to dampen the MAF signal? Or, write some delays into the code to smooth out the peaks.
Old Jan 22, 2009 | 01:27 PM
  #23  
JustinHoMi's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 273
Total Cats: 1
From: Hillsborough, NC
Default

The signal isn't linear. At high air flow the changes in rate are very small, and at low air flow they are large. If I were to dampen the signal enough to smooth out the low air flow area, I'd be afraid that it would damage the signal up high.

That said, I am testing out a different MAF circuit that will help to a degree... but the signal will still be noisy.
Old Jan 22, 2009 | 02:44 PM
  #24  
patsmx5's Avatar
Elite Member
iTrader: (16)
 
Joined: Aug 2007
Posts: 9,406
Total Cats: 559
From: Houston, TX
Default

My $0.02. WHY do you need this? What is MS gonna do with this information? Seriously? You can't run TPS based acceleration enrichments with this, and MS looks at MAP (or MAF in your case) to do it's thing. What is gonna change if MS knows it's at idle, not, or WOT?

And you 100% can't sneak a vac line to MS?
Old Jan 22, 2009 | 03:11 PM
  #25  
JustinHoMi's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 273
Total Cats: 1
From: Hillsborough, NC
Default

I'm not sure what you're asking. I answered your questions in my last 2 posts.

In summary: the code is configured so that AE kicks in upon partial throttle application. Additionally, I want to go into open loop on full throttle application.

And no, cheating is not an option.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mikeflys1
Miata parts for sale/trade
15
Oct 27, 2018 02:19 PM
Elfering
MEGAsquirt
17
Dec 16, 2016 06:44 PM
Trent
WTB
2
Oct 1, 2015 12:15 PM
aidandj
General Miata Chat
1
Sep 15, 2015 12:27 AM
albumleaf
WTB
0
Sep 10, 2015 09:28 AM


Thread Tools
Search this Thread

All times are GMT -4. The time now is 10:46 AM.