In my endeavors to program the digital instrument cluster I am making I have been working on the trip computer aspect of it. While doing this, I thought to myself, would this alone be something that a Fiero owner would benefit from. Then I remember back to all the messages about faulty fuel gauge. The answer I came to was possibly,depending on the individual owner and how this is integrated into the rest of the car.
Question is, does anyone else agree with me?
This is a trip computer that can display trip distance, instant and average M/P/G, distance to empty, gallons used or remaining, etc. Now, considering that this is a new project, I have nothing set in stone in relation to design but so far the code is working good. I need to install this into one of my cars and give it a try.
The only connections needed right now is battery 12V, switched ignition power, ground, speed sensor, and a feed from one of the injector leads which can be connected at the ecu. If I get one put together, I will let everyone how well it works.
Does this sound like a good idea? Would anyone be interested? Four_hundred_86, I will send one to you regardless.
YES! i would love a fully digital cluster including a trip and odometer. i know there are after market clusters and of course the cavalier digi swap but nothing with the digital milage aspect of it. if you can do it, make it look good and make it affordable im in.
Still toying with the idea of making the instrument cluster for sale but not anytime in the near future. In the meantime, I may make up just the trip computer for those who are interested. That is why I am asking if just the trip computer, without the rest of the instrument cluster, would be wanted.
I've built a trip computer over 10 years ago, and sold a dozen or so to enthusiasts around the world. The problem I've experienced is that the regular (cheap) displays are not up to the temperature range that you encounter in a car. Those low-cost LCD displays are only good from 0C-40C (freezing to 100F) maybe, the more expensive ones or alphanumeric LED ones are quite expensive. This of course drives up the grand total and makes this unattractive to the majority of folks. We are all spoiled by asian made high tech that's made in high volume and sold for quarters. I once had someone tell me that a trip computer should not cost more than $10, because that's what a pocket calculator costs, and the components inside are the same. That's cr@p of course, but what he meant was valid.
Out of curiosity: what displays are you planning to use?
I've built a trip computer over 10 years ago, and sold a dozen or so to enthusiasts around the world.
Hi, Oliver. I am one of your customers for the Dash Scan II, and it is still working fine in my Formula. I believe that you use the injector pulse width information out of the ECM to compute fuel consumption rather than measuring it directly. As I've remarked before, in my car the average fuel consumption varies from actual cconsumption measured at fill-up by up to +/- 15%. It's still useful as an alternative to the notoriously inaccurate Fiero fuel gauge, and the instantaneous fuel mileage display is sometimes interesting to watch.
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I once had someone tell me that a trip computer should not cost more than $10, because that's what a pocket calculator costs, and the components inside are the same. That's cr@p of course, but what he meant was valid.
That low price would only be possible if you could manufacture them in batches of more than 10,000 at a time, if the basic design didn't change over a 40 year time span, and if they were to become as ubiquitous as pocket calculators. Few people appreciate the economies of scale available in high-volume electronic manufacturing if the end product is both simple and the functionality well-defined and stable. (Just how many ways can you implement a 4-function pocket calculator, after all?)
[This message has been edited by Marvin McInnis (edited 08-21-2012).]
im looking to get toms digital gauges in a 3800 im planning on in the next year. for a trip and an odometer id be willing to pay around $50 which i feel is in line with toms gauge prices and as long as quality parts are used with some sort of warrenty.
I have Tom's gauges and they are top notch in every way. I feel the same way as below.
Mike Parker
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Originally posted by Niterrorz:
im looking to get toms digital gauges in a 3800 im planning on in the next year. for a trip and an odometer id be willing to pay around $50 which i feel is in line with toms gauge prices and as long as quality parts are used with some sort of warrenty.
Yes, I know, thanks for the feedback! The ECM mileage output is accurate to about a half gallon on a tank of gas on my 87, so that sounds about right. The trip computer doesn't know about the cold start valve though, and after all it's only measuring injector time assuming constant pressure, which is not the case. Just as you said, it helped me prevent running out of gas, and it's often interesting to see current mileage... Now that I've got the 7730 in my 87, I had to throw out the old DashScan and now I'm working on a worthy successor...
Yes, I know, thanks for the feedback! The ECM mileage output is accurate to about a half gallon on a tank of gas on my 87, so that sounds about right. The trip computer doesn't know about the cold start valve though, and after all it's only measuring injector time assuming constant pressure, which is not the case. Just as you said, it helped me prevent running out of gas, and it's often interesting to see current mileage... Now that I've got the 7730 in my 87, I had to throw out the old DashScan and now I'm working on a worthy successor...
I was going to use an OLED 20 X 4 character display.
Interesting. OLEDs are good for temperature range compared to LCDs, but what about life expectancy? With the (graphical) OLEDs I've used burn in was quite an issue, so the image contents had to be shifted around quite a bit, and care had to be taken to make sure to use different areas of the display equally (wear leveling). Is that an issue on the character OLEDs? Are you going to mount the display in a separate box?
Well, I have an electrical prototype running on my desk, but it's going to be a whole new leage mechanically, electrically and software-wise. This time don't have the restraint to "mass produce" it, so I don't have to worry about component sourcing, BOM maintenance, total parts cost, etc. I'll only build very few of these, but it'll be a fun project:
The CPU will be a 64 MHz 32-bit PowerPC compared to an 12 MHz 8051 8-Bit Processor. Everyting is surface mount. I have added a real time clock to provide time, and CAN bus for expansion. There will be several circuit boards sandwiched together to make optimal use of space.
It has a sound generator to provide sound for park distance control, will be flashable through the CAN-Bus, etc. Right now I'm working on power management and I'm about done with PCB layout of the main board (there will be three). Next up is testing the data link to the 7730 with my prototype, weather was just too nice to spend any significant amount of time in front of the computer. But when I have something to show, I'll be sure to post something here...
Sorry, I have been busy the last few weeks and have had little time to devote to the trip computer. I am still going to make a couple and see how the do. The display choice has changed and will most likely go with a VFD (vacuum florescent display) which is readable in daylight environment and has the needed temp range. Time will tell.
I was looking for a bit more interest as to whether I am going to make this for sale or not. Until I have a finished item, price is also an unknown.
P.S. GPS can be included but will increase the price a fair bit and the complexity. .
It is a good idea, no doubt about it. It just adds complexity to something I want to keep as simple as possible. As it stands now, all that is needed for input line is battery 12V, switched 12V, dash light feed, ground, injector input tied into injector wire, and speed sensor from wherever. The pulse per mile setting has an auto-calibration function so that is not an issue. The vfd and menu button(s) can be mounted just about anywhere within reason.
I hope this peaks the interest of others. Fieroseblack, PM me if you are serious about wanting one of these. This goes for anyone else if interested.
I am going to contact Tom S. and see if he is interested in this for his clusters. This would allow him to replace the mechanical odometer and trip counter with a digital solution with some added features. I will let you know.
I would be seriously interested in a stand alone unit, dependent on price. I've been looking for something that would work, but a custom made, Fiero specific unit would be a much better option, worth spending more on.
Keep us updated!
------------------ Tim '87 GT Auto Med Red Metallic 78K miles Bay City, MI
[This message has been edited by trivet (edited 09-17-2012).]
I will post some images of the display (in the rough) to show some of the screens available and to get some input on what is included or what should be added/left out. If my camera work, I will post these on Sunday the 23rd. So far everything seems to be working on the test bench. I need to finalize the circuit board design and get a couple made up for testing. By that time I should have an idea what the price will be.
As promised, here are a couple photos to give an idea what is displayed. This comp has two trip counters count independent of each other. Of course there is the rudimentary odometer. At the moment I have a clock function programmed in but I may change that to an outside temperature display with freeze warning.
Trip B of course.
Here is the average MPG display. This is filtered so that small changes have very little effect whereas large changes will be displayed fairly quickly.
Instant MPG. Same style of filtering but with a much faster response.
This was the fun one. A distance-to-empty display is nice to have although this is an estimate, although a good estimate.
Now, there are two ways that I can do this. One is to allow the distance to vary with the driving style. Mainly the distance will increase with better driving and lower with more entertaining driving. The other is to do a calc to display the dte and not allow the range to increase but to only decrease as needed. The second is similar to what most US DTE displays work. The first is more in the direction of European and Asian cars. I tend towards the European style that can be confusing/annoying to use unsophisticated Americans.
Here is another nice display to have, a fuel remaining counter. If the needed information is set correctly, this should be accurate within a 1/2 gallon of actual. Keep in mind that this is an estimation and only is resettable for a full fill-up, nothing less than a full tank please. I may input the float level signal and allow for automatic reset and to adjust to the level in the tank.
For things to be as accurate as possible, there are a few variables that can be adjusted in the settings display. These include number of cylinders, fuel tank size from 5 to 25 gallons, speed sensor with auto-calibrate, injector flow rate, and more.
Any input is greatly appreciated.
I need to get a prototype made so I can test it in a typical application. Updates to come.
[This message has been edited by chetw77cruiser (edited 09-23-2012).]
I would be happy with odometer, 2 trip counters, Average MPG, Distance / Empty.
This is great work and if it could be plug and play for all Fieros. That would include conversions like 3.4L, 3.8 S/C, 4.9L, SBC. So everone could have one even if they had not converted to a digital dash.
Color filters are available, so red should not be a problem.
As far as plug and play, there is the need for a fed from one of the injector leads between the ecu and the computer. This should allow it to be used on vehicles regardless of what OBD system they have. The other main signals are speed and dash lights for dimming. The main idea is that it will work with just about any EFI engine installed in a Fiero. This should work on anything from a 2.5 to a V12 as long as it has fuel injection and a speed sensor.
For location or even an encloser, I have nothing in mind at the moment. I will have to measure a bit but I think the factory odometer could be removed and the faceplate modified to fit the display. The main electronics are separate of the display and could be mounter anywhere within reason. There will be 5 buttons needed that can also be located anywhere you chose.
Sorry for the slow progress. With the white stuff (snow) coming soon, I have been busy at work readying plow trucks for the winter. I have most of the code finished and will be working on the final version of the circuit. One question, what would be better, a clock or a temperature readout? The temp is mainly interior but can be changed to an outside temp indicator with freeze warning.
I would think the temperture display would be great. The sensor could be placed either outside or inside for reading. You could actually put two sensors a three way switch, (on-off-on) and toggle between inside and outside temperture sensors. Or in the case of some of us who already have one or the other on a rear view mirror or other display, you just set the sensor for the other. That way you can see both inside and outside temps.
One of the coolest things I have seen in awhile! the only thing I could think of that would make it cooler, besides the plug and play suggestion, is the location of the unit (which would drive it to a different shape I think.) If it could be located above the speedo side of the guages in the unused cutout it would at least make that gap make sense. Awesome ideas on this! I would be interested in a few!
I would think the temperture display would be great. The sensor could be placed either outside or inside for reading. You could actually put two sensors a three way switch, (on-off-on) and toggle between inside and outside temperture sensors. Or in the case of some of us who already have one or the other on a rear view mirror or other display, you just set the sensor for the other. That way you can see both inside and outside temps.
There will be no need for a switch, all this can be done in code and a button on the front.
