timed outputs?

Testing and development of Megasquirt 3

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Re: timed outputs?

Postby Peter Florance » Sat Apr 28, 2012 11:56 pm

JAM wrote:I was looking at the PG trans and it would be really easy to put a tps on for the use of gear position input as outlined in the analog section of this link
http://www.msextra.com/doc/ms3/speedgear.html

I am using 2 of the 3 spare 0-5 inputs with ADC's for fuel and oil pressure sensors and would like to use one for a VSS.... I can tell I am going to need more.

On another note i have just split the 5V ref from the tps 5V ref between tps/oil/fuel press, how many times can i split this signal before i run into trouble? :?:

I think a 5000 ohm TPS will not be an issue. There is some concern of additional noise from polyfuse as Vref is loaded more (protects Vref from short), but additional 1ma should not make any measurable difference.
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Re: timed outputs?

Postby JAM » Sun Apr 29, 2012 6:04 am

Peter Florance wrote:I think a 5000 ohm TPS will not be an issue. There is some concern of additional noise from polyfuse as Vref is loaded more (protects Vref from short), but additional 1ma should not make any measurable difference.


Thanks for the info. I have the tps and 2 of the honeywell style pressure sensors on the 5V ref pin of the MS3, so your saying adding another tps or another senor that requires 5Vref should not be an issue?
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Re: timed outputs?

Postby Peter Florance » Sun Apr 29, 2012 6:08 am

JAM wrote:
Peter Florance wrote:I think a 5000 ohm TPS will not be an issue. There is some concern of additional noise from polyfuse as Vref is loaded more (protects Vref from short), but additional 1ma should not make any measurable difference.


Thanks for the info. I have the tps and 2 of the honeywell style pressure sensors on the 5V ref pin of the MS3, so your saying adding another tps or another senor that requires 5Vref should not be an issue?

Yes, I would not hesitate to try it.
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Re: timed outputs?

Postby Black99rt » Tue May 01, 2012 6:23 am

http://www.acddragparts.com/products.html

Anyone else have examples of controllers whose features we can benchmark against? I think biondo probably makes boxes for this as well.
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Re: timed outputs?

Postby JAM » Tue May 01, 2012 9:18 am

Black99rt wrote:http://www.acddragparts.com/products.html

Anyone else have examples of controllers whose features we can benchmark against? I think biondo probably makes boxes for this as well.



Biondo has the MEGA series of delay boxes. I have used this unit (the mega 400) and a one thing I like is that it has a reaction time tester. i would use that in the lanes before a run to help set my delay. this box has tons of features most of which i find unnecessary.

I have used the Dedenbear lightning box and it was a good unit, couples directly to a digital dial in board which is very nice so you never have to wonder if the dial matches the delay box etc.

K&R pro cube is a popular box and very basic. it has 2 or 4 timers depending on which one you buy. one positive is that it has buttons (toggle levers) that are easy to operate with gloves.

The one thing i like about the mega is that it has an adjustable transbrake safety lockout. I learned about the benefits of this this the hard way... 2 different ways :oops:
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Re: timed outputs?

Postby JAM » Tue May 01, 2012 9:23 am

In addition to the a transbrake safety switch, another feature that would be nice would be an SLE

The dedenbear and i believe the mega are adjustable which i really like, the KR is just on/off with a preset time ( I cant remember what it is set to but adjustable is much better IMO)
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Re: timed outputs?

Postby ashford » Tue May 01, 2012 9:52 am

JAM wrote:In addition to the a transbrake safety switch, another feature that would be nice would be an SLE

The dedenbear and i believe the mega are adjustable which i really like, the KR is just on/off with a preset time ( I cant remember what it is set to but adjustable is much better IMO)



a disable transbrake after something like 15mph would be nice, as i still need the tb for reverse. i am deftly scared of hitting the tb button when i reach down to shift.
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Re: timed outputs?

Postby JAM » Tue May 01, 2012 3:04 pm

ashford wrote:
JAM wrote:In addition to the a transbrake safety switch, another feature that would be nice would be an SLE

The dedenbear and i believe the mega are adjustable which i really like, the KR is just on/off with a preset time ( I cant remember what it is set to but adjustable is much better IMO)



a disable transbrake after something like 15mph would be nice, as i still need the tb for reverse. i am deftly scared of hitting the tb button when i reach down to shift.


you have a pro brake if it is needed for reverse. I do as well.

I had a couple bad experiences with accidental t-brake activation, most boxes have a lock out after shifting gears and a timer after first tbrake activation. I set my timer so that it would lock out for a few seconds, far enough into the run that it had already shifted. I had a situation where my shift solenoid did not drive the shifter into the hi gear and it went up on the revlimiter way down track because it was still in low gear. In the chaos i clipped the button and of course due to the delay it locked the trans up for many seconds, probably around 100mph. Not a fun experience.
And actually as to mph i would say time is probably better. One other situation was at the hit my hand came off the steering wheel, when i put it back on the wheel i clipped the button, and again it locked it up.
This is why the timer is built in, i just did not have it turned on. It can happen because generally you have the button very close to the thumb, when the hands come on and off ....its possible
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Re: timed outputs?

Postby jsmcortina » Tue May 01, 2012 3:14 pm

That lockout sounds like a good safety feature.

Certainly TB lockout > x mph makes a lot of sense if VSS is fitted.
Wouldn't also TB lockout > y rpm be a simple one too ?

The timed option I can see too, just a matter of making sure there isn't an instance where you enable the TB, want to disarm it and then the code won't let you re-arm it again ?

How about if you have to hold the button down for say 1/4 second before the TB locks ? That way if you touched it by accident it would be ignored.

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Re: timed outputs?

Postby JAM » Tue May 01, 2012 3:25 pm

jsmcortina wrote:That lockout sounds like a good safety feature.

Certainly TB lockout > x mph makes a lot of sense if VSS is fitted.
Wouldn't also TB lockout > y rpm be a simple one too ?

The timed option I can see too, just a matter of making sure there isn't an instance where you enable the TB, want to disarm it and then the code won't let you re-arm it again ?

How about if you have to hold the button down for say 1/4 second before the TB locks ? That way if you touched it by accident it would be ignored.

James


Yes, if vss is fitted i agree.
For launch........ if i launch at 4500 rpm, then disarm after 4600 rpm?
as far as re-arm the delay boxes have the 'accidental hit' feature as well, yes that is good, if you are staging and by accident hit the button before second staged is on, you can get timed out and the red eye will turn on. its a bad feeling to have your car stuck for a couple seconds when going into the beams. the other time this can happen is driving in the pits and turning a little dinky steering wheel ..... dont ask me how i know all of this stuff :?
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Re: timed outputs?

Postby jsmcortina » Tue May 01, 2012 3:41 pm

JAM wrote:For launch........ if i launch at 4500 rpm, then disarm after 4600 rpm?

I run a manual so have no TB experience yet.
What RPMs are you doing when you enable the TB though? Surely just off idle?
i.e. come up to line, enable TB, bring up revs, launch!

So the arming rpms could be more like 1500 ?

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Re: timed outputs?

Postby JAM » Tue May 01, 2012 4:01 pm

Yes, you are correct. If it disables actuation of solenoid then you would want the value to be just off idle. (as long as it does not disable the current actuation) most drag cars probably idle 1200 to 1400 rpm

What I was referring to earlier is a SLE (starting line enhancer)
After burnout I actuate an air cylinder which is inline with my throttle cable. the fuel pedal falls to the ground, i have no throttle ability at all.

here is my process:

1.)I stage the car at idle (no throttle control at this point)
2.) bump it into the beam with the foot brake
3.)I hit the transbrake
4.) release the footbrake
5.) release transbrake at 1st amber
5.a) *See below
6.).5 to .6 seconds before the transbrake lets go, the air cylinder collapses, and pulls the throttle wide open
7.)wait for the brake to release


*I have a 'bumpdown' on the top of the steering wheel. If I think i missed the light, i can push this button (after the tbrake release) for every time i hit the button it will take .010 (or whatever i have it set at) out of the delay time. So if i hit it twice it would be .020 etc as many times as you can hit it before the brake lets go. this would be a cool feature
but require additional input

in picture delay box is mounted on left, you can see shift solenoid on shifter on right, buttons on wheel are transbrake and burnout, bumpdown on top of wheel. you can somewhat see air cylinder on gas pedal



Image
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Re: timed outputs?

Postby ashford » Wed May 02, 2012 5:29 am

deactivating apply after x rpm would work well too as long as it holds current activation. the only issue i see is if i accidentally let go of the button when backing up it need to return to setpoint if it is really low, or reactivating it again if you get a tire spin and let off if it is set too high.

my car on the trans brake stalls to about 2800 then anywhere upto 4500 when the turbo spools depending on what i am using for launch settings or using it at all.
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Re: timed outputs?

Postby jsmcortina » Wed May 02, 2012 6:16 am

ashford wrote:deactivating apply after x rpm would work well too as long as it holds current activation. the only issue i see is if i accidentally let go of the button when backing up it need to return to setpoint if it is really low, or reactivating it again if you get a tire spin and let off if it is set too high.

But you aren't backing up at 2000rpm though??[/quote]
The logic I'm thinking of is:
if tb = off
if button_pressed AND rpm < rpm_arming_limit then tb = on
else
if button_not_pressed then start tb timer
endif

So once the TB is on it doesn't pay any attention to the rpm, but when the TB is off you need to press the button and be below your chosen rpms.

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Re: timed outputs?

Postby JAM » Wed May 02, 2012 9:27 am

jsmcortina wrote:
So once the TB is on it doesn't pay any attention to the rpm, but when the TB is off you need to press the button and be below your chosen rpms.

James


the way I see it, for my application this would work great.
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Re: timed outputs?

Postby JAM » Thu Jun 07, 2012 10:30 pm

Ok, so here is the next one for the dragracing cool feature list:

Ignition advance based on time....... from the release of the transbrake it starts... maybe the input would be a graph with time on the X axis and ignition advance on the Y axis.
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Re: timed outputs?

Postby jsmcortina » Fri Jun 08, 2012 12:28 am

Something like the "Timed Retard After Launch" feature?

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Re: timed outputs?

Postby ashford » Fri Jun 08, 2012 7:05 am

i used the retard after released feature and it helped greatly. the tires didn't blow off when released. i got back to back 1.51 60ft times
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Re: timed outputs?

Postby JAM » Fri Jun 08, 2012 9:25 am

jsmcortina wrote:Something like the "Timed Retard After Launch" feature?

James


Exactly.... :D

but i am confused at what output activates the start of this timer, can it be activated when the transbrake releases
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Re: timed outputs?

Postby ashford » Fri Jun 08, 2012 1:36 pm

JAM wrote:
jsmcortina wrote:Something like the "Timed Retard After Launch" feature?

James


Exactly.... :D

but i am confused at what output activates the start of this timer, can it be activated when the transbrake releases

the timer starts when the launch control is released
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