Software writers, I need your help.

[Amianthus]

We are planning to have an annual dyno event for charity in NE IA. Last year was a big success. But there was a problem. We had a hard time with the dyno getting accurate numbers due to the age of the machine. We also had no way to print this stuff out for the participants. Well, what I want to do is make a program that will calculate HP, torque, and print it out on a chart.

I have the formulas, conversion charts, voltages (can an i/o port handle 10 vdc up to 12 vdc?), etc. But I have no idea how to write code. I suppose, if someone has an Apple IIe, I could do it in basic. But fat chance of this happening. Can anyone out there help me out. Let me know what I would need to get his done.

I have an idea of what needs to be done, but no idea on how to do it. Any help would be helpful.

 

[Lurch]

I got an Apple II.



Lurch

 

[Morphious]

I could help you out in writing the software, but you are not going to be able to put the voltage directly into the PC I don't think. I don't know for sure, but believe that the serial port can only handle +- 5 VDC.



Morph.

 

[PRout]

A nice Excel spreadsheet would probably do the job for ya. .



Too bad you dont have someone in the area that can make up really fancy one for TDR members.

 

[Amianthus]

I didn't think it would allow a 10 vdc input. Since most circuts of the computer run on 5 vdc. I can modify the input signal to the i/o port to be below the 5v limit. It will take some modifications to the formulas I was gonna use, but I can do that. Other than that, how hard would it be? Which would be the better platform to use, Windows (I don't know about this) or DOS (for better speed and function dedication)?

 

[Morphious]

Yes, lowering the voltage would work, but the problem I see is the serial port doesn't act like an o scope, it is digital, meaning that the voltage is either up or down, which signifies a bit. 0 or 1. You will need to run your analog signal through an A/D converter and then into the Serial port for the application to recieve it. You can use windows, I do things like this all the time, with the manufacturing systems I design. I have used serial ports to control million dollar laser beam recorders and such.



If you have any questions, email me: -- email address removed --

 

[Amianthus]

I was afraid of that. I don't know enough about the i/o port yet, but I suspected that might be the case. Now comes the treat of converting the 0-10vdc analog input signal to a useable digital signal. Wonderful. I think more about it in the morning when I'm not so depressed about my beer going flat. I'll email you more about my plans and stuff later on. If anyone else has more ideas, keep them coming.

 

[Morphious]

Here is a good link that tells you all about the Serial port:



http://www.ibiblio.org/mdw/HOWTO/Serial-HOWTO.html



and here is a link that shows how to build an A/D converter:



http://www.hut. fi/Misc/Electronics/circuits/ad_serial.html



Morph.

 

[OO]

Here is an entertaining link about trying to keep beer from going flat.

http://www.halfbakery.com/idea/Beer_20Ice_20Cubes

Those lime cubes sound interesting.

 

[docdyno]

There are a number of data acquisition systems made that are designed to do just what you are desiring. They take an analog input and process it to interface with a software package and display on your PC. Many have drop down menus to facilitate the production of comparison graphs for torque and HP. We use a number of them in our dyno labs. I may have some information or possibly even a loaner for a charity event. There will be a slight learning curve needed to formulate the set-up, but it sounds like you will have no problem. Software and hardware come as a package. You will need some sort of strain gage transducer to measure torque; but your Dyno, no doubt, has one. Interface for most of these is currently USB & Windows based. Very few engineering programs are written for Apple. Let me know if you need additional data. -- email address removed --

 

[Amianthus]

Here's the deal with the Dyno.

docdyno, Morphious thanks for the replies.

Here's our situation. We've got a Sun Road-A-Matic eddy brake dyno. The dyno is somewhat aged, but still has all the inputs and capabilities of a 700 HP dyno. The problem is that the control box is only "rated" to 240 HP. It can measure tractive effort to 2400 lbf pretty accurately, though. There are some more things that I need to get with Sun on regarding more of the specifics of this dyno.

Last year we could bring it up to ~330 HP before she overloaded. What we're trying to do is expand this limit, generate engine torque readings, and graph a run.

Mathematically speaking, the formulas are easy and plugging them into a computer shouldn't be hard. This machine has an external connection that will plug into other Sun diagnostic equipment. There are only two outputs and a ground on this connection. Speed (in MPH) and HP or Tractive effort (depending on how the machine is set). Speed is a (pos)0-10vdc signal and TE is a (neg. )0-10vdc signal. Analog of course.

Using TE, Speed, Rear End ratio, Tire Size (possibly), I can extrapolate engine torque and HP at any given point. The ratio for the TE signal is . 00445vdc to 1lbf. The speed signal ratio, I will have to get from Sun.

Yes, the machine has a strain gauge and as far as I tried to check it's calibration, it was accurate. It also uses a photo tacometer to measure speed on both rollers (it eases the brake if you start to walk off the rollers).



So what do you think? Is this feasable. I am very interested in the software and hardware packages you have mentioned, docdyno. I will send you a PM with my phone number and perhaps we can talk in person. Or PM me with a number and a time and I will contact you.



Morphius, if docdyno already has the equipment to do this, that may make the custom program and electronics unnecessary. But given the age of this machine, I may still need your help. BTW, the link for the A/D converter didn't come through.



As an FYI, we gave monies from this event to the Rochester Ronald McDonald house. This year should be the same. Maybe we'll add a few more charities.



Thanks again for the replies. Please keep them coming.

 

[ACoyle]

If you can't get what you need from DocDyno in a package, then what you need is an analog to digital converter board for your PC. They should not be too hard to find.



The formulas are probably a linear regresion or a least fit Polynomial square, if I remember my project correctly. If you have them it is easy with the board in place.



The serial port is not an easy go of it.



http://www.microdaq.com/



Try that link for some ideas.

 

[fest3er]

How accurate do you want it to be? You might be able to use the line and microphone inputs (conditioning the signal appropriately, of course), but the accuracy and precision *might* suffer some.



But it might just be better to simply buy an inexpensive A2D/D2A card (PCI or PCMCIA, depending on your hardware).



Writing the program shouldn't be too difficult. It could probably be done on a single floppy, OS and all. Were you to use Linux or BSD, I could do it easily enough.



But, most likely, you may just find the software you need on the net.



Good luck!

Fest3er