Servo driver?

[Tim_Duggan]

Tim,

As per David's post http://arduino.cc/en...rduinoBoardNano would probarly suit, I have a full Arduino kit if you want to play with it for few weeks. Been using it to experiment with some similar ideas.

Hmmm me too

My project needs on chip PWM to do what i want

Greg,

Check out the ATtiny. You can program it with an arduino as a master, then it will run independently and supports PWM in/out. Similar size to a 555.

Tim

 

[Tim_Duggan]

Tim

Yes the nano is the end goal.

As far as multiple circuits thy can all run in one chip 7555.

Don't worry about the pressure in the line it won't hurt any thing. Have my 1.01 restricted to a .080 orifice and it works fine at 90MPH.

There are a few glow drivers already out there that will adjust to the plug heat.

As far as fuel pressure it will not mater it will do what it dose now control the flow at different RPM's.

The system will work off the 3rd channel needle it will just make adjustments as far as the needle will travel.

This will all depend on the needle and how much the flow will change with the adjustment.

You will have to be in the ball park to start and the needle will only be able to adjust very little. It will not take much to change the ex gas temp.

At low speed it will run very lean to try and raise the temp. this will be a good thing as the throttle will be sharp as a tack.

It all sounds good on paper will see if it pans out.

so hows that nano pretty easy to wright the code? will get one it is on my list. heck thy have them at Radio shack down the street.

It is just easer to experiment with this chip for now. built this set up in less time than writing one line of code.

David

The learning code part is the time killer for me, but I have to be straight up on this - the arduino has really rekindled my interest in electronics in a big way! I've been in a rut with it for the last 15 or so years, and this thing can do stuff that I never thought possible without spending a small fortune back then. Has been bad for my boating though - not much work getting done on boats! There are some good tutorials on the web, as well as some books for self paced learning. "Programming Arduino, getting started with sketches" by Simon Monk is what I'm reading at the moment and is not difficult to follow. The Nano is small and light, but this stuff can be done even smaller! The Nano is good for learning though. Easy to work with. One thing I did find while doing some websurfing - the servo's work better with their own power feed than taking power from the arduino.

I'd be hesitant to go with lean low to mid range, especially on smaller boats. From experience gained with certain carbs and trying to optimise them, it's much better to be slightly rich in that area. Particularly on throttling down. if you wanted to avoid having the needle change for EGT at partial throttle but still wanted to use a 555 circuit, perhaps a simple microswitch on the throttle arm to disable the circuit below full throttle could work?

A lot of the inboard glow drivers on the market are too big / heavy for small boats like 20 riggers, and to be honest - way more expensive than the parts required to get it done for a "proof of concept". If I'm going to make a system that does what I want, I can integrate them all together. One of the beautiful things about using logic to do it is conditions can be set, say for example if the mixture is fine tuned by the EGT, we could tell it to only make adjustments when the throttle is at a certain position, or if the head temp is in a certain range etc etc. The possibilities are amazing.

 

[dwilfong]

Tim

Yes the nano is the end goal.

As far as multiple circuits thy can all run in one chip 7555.

Don't worry about the pressure in the line it won't hurt any thing. Have my 1.01 restricted to a .080 orifice and it works fine at 90MPH.

There are a few glow drivers already out there that will adjust to the plug heat.

As far as fuel pressure it will not mater it will do what it dose now control the flow at different RPM's.

The system will work off the 3rd channel needle it will just make adjustments as far as the needle will travel.

This will all depend on the needle and how much the flow will change with the adjustment.

You will have to be in the ball park to start and the needle will only be able to adjust very little. It will not take much to change the ex gas temp.

At low speed it will run very lean to try and raise the temp. this will be a good thing as the throttle will be sharp as a tack.

It all sounds good on paper will see if it pans out.

so hows that nano pretty easy to wright the code? will get one it is on my list. heck thy have them at Radio shack down the street.

It is just easer to experiment with this chip for now. built this set up in less time than writing one line of code.

David

The learning code part is the time killer for me, but I have to be straight up on this - the arduino has really rekindled my interest in electronics in a big way! I've been in a rut with it for the last 15 or so years, and this thing can do stuff that I never thought possible without spending a small fortune back then. Has been bad for my boating though - not much work getting done on boats! There are some good tutorials on the web, as well as some books for self paced learning. "Programming Arduino, getting started with sketches" by Simon Monk is what I'm reading at the moment and is not difficult to follow. The Nano is small and light, but this stuff can be done even smaller! The Nano is good for learning though. Easy to work with. One thing I did find while doing some websurfing - the servo's work better with their own power feed than taking power from the arduino.

I'd be hesitant to go with lean low to mid range, especially on smaller boats. From experience gained with certain carbs and trying to optimise them, it's much better to be slightly rich in that area. Particularly on throttling down. if you wanted to avoid having the needle change for EGT at partial throttle but still wanted to use a 555 circuit, perhaps a simple microswitch on the throttle arm to disable the circuit below full throttle could work?

A lot of the inboard glow drivers on the market are too big / heavy for small boats like 20 riggers, and to be honest - way more expensive than the parts required to get it done for a "proof of concept". If I'm going to make a system that does what I want, I can integrate them all together. One of the beautiful things about using logic to do it is conditions can be set, say for example if the mixture is fine tuned by the EGT, we could tell it to only make adjustments when the throttle is at a certain position, or if the head temp is in a certain range etc etc. The possibilities are amazing.

Yes it dose open up a whole new world. Just wish I had the patents to learn it. I will take a shot at it the benefits are worth the time spent.

Wold be nice to get some one involved that already is up to speed with the code.

the last person that I talked with was a dead end gust lip service with a swollen head.

I will get one and then we can compare notes for the end results.

I know that many are very secretive about what thy are doing. But as I see it from my point of view it is for the greater good not self gratification.

There are not many of us that this would apply to as fare as a end user just a hobby for the enjoyment. Hope we can all keep it that way.

David

 

[Tim_Duggan]

Wold be nice to get some one involved that already is up to speed with the code.

the last person that I talked with was a dead end gust lip service with a swollen head.

I will get one and then we can compare notes for the end results.

I know that many are very secretive about what thy are doing. But as I see it from my point of view it is for the greater good not self gratification.

There are not many of us that this would apply to as fare as a end user just a hobby for the enjoyment. Hope we can all keep it that way.

David

David,

You and I are on the same page here! Not doing it for money or an edge, just opening it up for everyone who has a similar interest. In fact the whole Arduino thing is in a similar vein. I have to thank you for your video again, it's given me the kick in the azz I needed to get this happening faster than I'd been progressing.

When you get a Nano, there is a sample script in the Arduino software already that allows the servo to sweep based on input from a 100K trimpot. (script is arduino speak for code). Pretty much exactly what you have with the 555 without having to learn any code at all. I've had it working on my desk at work during a lunch break. it looks like this;

// Controlling a servo position using a potentiometer (variable resistor)

// by Michal Rinott <http://people.intera...rea.it/m.rinott>

#include <Servo.h>

 

Servo myservo; // create servo object to control a servo

 

int potpin = 0; // analog pin used to connect the potentiometer

int val; // variable to read the value from the analog pin

 

void setup()

{

myservo.attach(9); // attaches the servo on pin 9 to the servo object

}

 

void loop()

{

val = analogRead(potpin); // reads the value of the potentiometer (value between 0 and 1023)

val = map(val, 0, 1023, 0, 179); // scale it to use it with the servo (value between 0 and 180)

myservo.write(val); // sets the servo position according to the scaled value

delay(15); // waits for the servo to get there

}

 

[dwilfong]

Wold be nice to get some one involved that already is up to speed with the code.

the last person that I talked with was a dead end gust lip service with a swollen head.

I will get one and then we can compare notes for the end results.

I know that many are very secretive about what thy are doing. But as I see it from my point of view it is for the greater good not self gratification.

There are not many of us that this would apply to as fare as a end user just a hobby for the enjoyment. Hope we can all keep it that way.

David

David,

You and I are on the same page here! Not doing it for money or an edge, just opening it up for everyone who has a similar interest. In fact the whole Arduino thing is in a similar vein. I have to thank you for your video again, it's given me the kick in the azz I needed to get this happening faster than I'd been progressing.

When you get a Nano, there is a sample script in the Arduino software already that allows the servo to sweep based on input from a 100K trimpot. (script is arduino speak for code). Pretty much exactly what you have with the 555 without having to learn any code at all. I've had it working on my desk at work during a lunch break. it looks like this;

// Controlling a servo position using a potentiometer (variable resistor)

// by Michal Rinott <http://people.intera...rea.it/m.rinott>

#include <Servo.h>

 

Servo myservo; // create servo object to control a servo

 

int potpin = 0; // analog pin used to connect the potentiometer

int val; // variable to read the value from the analog pin

 

void setup()

{

myservo.attach(9); // attaches the servo on pin 9 to the servo object

}

 

void loop()

{

val = analogRead(potpin); // reads the value of the potentiometer (value between 0 and 1023)

val = map(val, 0, 1023, 0, 179); // scale it to use it with the servo (value between 0 and 180)

myservo.write(val); // sets the servo position according to the scaled value

delay(15); // waits for the servo to get there

}

Tim what I found is that 100k is more than the servo need to run a full Cly it was more like 53k to 23k is a full travel range. this may not apply with the logic circuit in the system you are using. the narrower range will make for a smaller window for the movement. this will make the reaction faster to temp change. the thermistor range will change the reaction time. theses are the things to learn with real world testing with the chip.

I will continue with my experimentation with the chip and post the results.

Glad to here we are on the same path.

 

[Tim_Duggan]

David,

You have one major advantage over me in that you have the datalogger. I haven't got that far yet (I know I know - I should have one!) and still rely on "seat of the pants", radar, and lap times.

What boat are you planning on doing the initial on-water testing with?

Tim

 

[dwilfong]

Of course it will be my test mule Brutus. A SGX 90 with a 1.01 in it. Have plenty of room in the box to put every thing in it.

that and the billet pipe has plenty of meat to hook up the thermal coupler.

That brings up other questions where is the best point to check the ex gas temp.

 

[Tim_Duggan]

That brings up other questions where is the best point to check the ex gas temp.

My thoughts would be to do it as close to the exhaust port as possible, but that might not be very practical. Perhaps someone with experience in logging EGT can chime in?

 

[dwilfong]

I have lodged some EGT on my 45RS. I put the probe right in the header to get the reading.

If you look at where the OS FI system thy check it at the same point.

If you are looking for the burn temp I think this is the spot.

Don't think that the temp in the pipe center will be much different. But the burn temp is what i think you need to adjust the needle.

There was some talk about how compression will change ex gas temp because of the expansion rate of the gasses.

Sooo check it at the closes point or after it expands into the pipe?

The temp in the pipe center is where the wave travels the most so this should change the tune the most.

But checking it at the port will tell you what the burn temp is

In my thinking burn temp is what will give the most advantage to the tune..

Just my take on it.

Hope some more will give some of there wisdom.

 

[Tim_Duggan]

"The Exhaust gas temperature is taken mid-pipe to get an average temperature without interference from combustion temperature."

I found this interesting quote at the following page;

http://www.suzuki-rg500.com/exhaust.htm

 

[dwilfong]

"The Exhaust gas temperature is taken mid-pipe to get an average temperature without interference from combustion temperature."

I found this interesting quote at the following page;

http://www.suzuki-rg...com/exhaust.htm

Yes for designing a pipe the middle will be the temp you need but for fuel mix control I think the burn temp will be more important.

With the head temp stabilized it will be easer to control the burn temp.Remember we are trying to control the mixture not collect data for a pipe build.

Yes knowing the center pipe temp will also be needed to build the right pipe. I can log two ex temps at the same time with the Eagle tree.

Will see what is what when I do it the next time.

 

[Tim_Duggan]

Agreed that it's about designing a pipe, but the inference about combustion temps influencing EGT readings seems relevant.

When you logged EGT previously at the header, did you keep the log data file? Any chance you also logged servo positions at the same time? It would be really interesting to know if there is any time delay between changing the needle setting and the EGT responding.

 

[dwilfong]

I was thinking about how load on the eng changes the rich and lean condition in the eng.

with this new pipe I have the eng would lean out when the load was less in the straits. with the old pipe it did not do this.

every thing in the eng and prop set up the same.

so what is changing the way the mix burns with different loads? would have to be the way the gas expands after the burn.

So this would change the burn temp. more load the higher the expansion pressure would be to push the load.

Higher pressure = higher temp. more fuel would keep the temp down.

this would change the pressure wave to the pipe.

I still say check burn temp as close to the port as possible.

Never logged needle position. but this can be done.

 

[Jim Caldwell]

Good work guys, You are well on the way to extracting more reliable power from these motors.

 

[Tim_Duggan]

I was thinking about how load on the eng changes the rich and lean condition in the eng.

with this new pipe I have the eng would lean out when the load was less in the straits. with the old pipe it did not do this.

every thing in the eng and prop set up the same.

so what is changing the way the mix burns with different loads? would have to be the way the gas expands after the burn.

So this would change the burn temp. more load the higher the expansion pressure would be to push the load.

Higher pressure = higher temp. more fuel would keep the temp down.

this would change the pressure wave to the pipe.

I still say check burn temp as close to the port as possible.

Never logged needle position. but this can be done.

I have had this same phenomenon with a 67 rigger. Never truly understood why, but went for the slightly richer needle approach to lessen it. Would be better to understand the "why" rather than trying to apply a band-aid.

I guess what we need to know re: the EGT probe position is if the output of the sensor can be more useful in terms of actually driving the servo, depending on it's position in the pipe. If the time delay is too great or the temp shift from the thermocouple not specific enough due to other influences (combustion temps, close proximity to the pipe walls etc.) Logging EGT at both spots, and mix servo also on a run at the same time might give us the answer.

 

[dwilfong]

I have bin doing so checking on thermal couplers and there output and the heat range thy run in.

It is very interesting how some react to temp different than others. the range of the mv output is of different degrees.

some react different and have less variation. it looks like the J type have a smaller range and I think the smaller range will work better as the window is smaller.

their are also resistors that will handle the temp range and give a ohm range output.

I have bin also looking at my RS 1.01 case and with the head setup I use I can put the sensor right in the top of the ex port very close to the window.

I will set up a eng with the sensor at the port and at the center of the pipe and see what is what.

I also think the needle should be on the end of the spray bar for quick reaction.

I don't think this will change any thing as far as what the pipe dose to the tune. the pipe is the pipe and it dose what it dose. But it will give a consent ex gas temp to the pipe and a perfect burn. this will take most of the variables out of the mix.

Buy changing the fuel mix it will adjust to the changing cyl pressure from load change and pipe charging by measuring the burn temp and keep the song sweet.

 

[Tim_Duggan]

Just talking out loud here and fully appreciate the mechanical difficulties, but other than just tweaking the mixture to alter EGT - what about altering the pipe length mechanically in line with the changing EGT? Or tricking the pipe thermally with water injection?

 

[Jim Caldwell]

I don't think you are going to be able to change the lenght of the pipe. I built a cable adjustable pipe for a 125cc motor and could not pull it in at full out with a 18" lever arm. Made for quick adjustment in the pit though!

 

[RodneyPierce]

Jim it has successfully been done before by a few in the UK. Just using a hi-torque servo as the push/pull device.

 

[dwilfong]

Lets think why we need to change the pipe length.

In a boat at full song wide open it will load in the corners and change the load on the eng. eng need more fuel to compensate for this or the EGT will change. this changes the tune length for the pipe. the eng temps go up with load and this changes the burn witch also changes the EGT.

Now if we control the water temp and the fuel mix keeping the EGT stable the pipe can do what it was designed to do.

Also their are pipe designs that will work with a wider power band. the two and seen some starting to think 3 cone rear sections.

Don't mess with the pipe mess with the EGT and cylinder temp. Give the pipe what it needs a stable wave form to work with.