Building a Better Speedometer
Vložit
- čas přidán 8. 07. 2024
- The speedometer in my DeLorean failed, and then failed again, and kept failing. I got tired of replacing the same bad part over and over again, so I made something better: a clip-on digital speedometer using a hall sensor, an Arduino, an LED display, and some 3D-printed cases.
More details about this project, including the GitHub repo for the Arduino source, can be found at www.tmproductions.com/repairs...
Timestamps:
00:00 Intro
00:40 The Speedometer
00:50 Why Only 85 MPH?
01:16 Back to the Future's Solution
01:47 The Lambda Counter
02:09 Why?
02:44 Testing the Cables
03:02 A Power Drill?!?
03:16 One Part To Go
03:24 The Angle Drive
03:39 Why Is It There?
03:50 How It Works
04:11 Testing the Angle Drive
04:24 What Do I Do Now?
05:07 My Solution
05:16 The Hall Sensor
06:30 Figuring Out Distance Per Pulse
07:19 Dealing With Sensor Noise
08:16 How To Show Zero When Stopped
08:38 The Display
09:18 Mounting the Display
09:47 Daylight Readability
10:11 Arduino Case and Heat Set Inserts
10:29 Providing 5v Power
10:52 Alternative: Electric Motor Driving the Stock Speedometer
11:15 Alternative: GPS for Speed
11:28 Alternative: Pre-Built GPS Unit Driving the Stock Speedometer
11:40 Alternative: Automatic Transmission Governor Output
11:58 Final Thoughts
Help support this channel:
* Subscribe -- czcams.com/users/joeangel...
* Share this video -- • The DeLorean's Automat... - Auta a dopravní prostředky
If you’re getting a lot of RF noise, you can try using a shielded cable that is grounded on the monitor side but left open on the sensor side
I actually have a bunch of shielded wire that I've been meaning to use for this, but never got around to installing it. I'll likely do it when I upgrade this from the Arduino Mega to a PCB with an ESP32 that's sitting on my desk waiting to be finalized.
I've also been trying to find a good source for shielded CAN bus wiring for DIY projects, since I have some plans for that as well.
Great stuff! I’ve never seen a Speedo pickup from the front wheel hub. I can understand the motivation given the rear trans.
My VW Vanagon (Type 2, T3) had a front wheel hub sender for the speedo. It just didn't need the goofy 90° gearing that the Delorean uses.
@TheVgonman I’ve been trying to find a speed sensor that would mount the same way that the angle drive does. Having a drop-in replacement would be nice. I’ve also looked at how I’d mount a VSS ring to the front axle, but it’s not at all clear fire I’d do that.
You sir have got my full attention. Your style of editing reminds me of good old car shows from the beginning of the 00's on Speed Channel mixed with the quirkiness of new medias. I will be looking forward at your future videos 👍
Thanks -- glad you liked it! I'm hoping to get production figured out to the point that I can get something up every two weeks or so, so if all goes well you won't have to wait too long!
Here for the Delorean content. Would like to see more about the mods you’ve done. Push button start etc.
That’s definitely on the list. My keyless ignition is very custom, but the same principles will work with an off-the-shelf kit, too.
I do plan on doing a video on my keyless ignition as it exists now, before I do some upgrades to the electronics behind it. And I have a number of mods planned for the future, too. But first I have to get these videos out faster so I have time to work on the mods!
Love this channel.
This is super dope, thank you you gave me lots of ideas for how to fix my speedometer on my 1987 300zx
Thanks! I know some DeLorean owners have had good luck with Speedbox, which is a GPS-based electric motor thing that drives the original speedometer, if you want to try something that works more out of the box. I just wanted to do something a bit different. Good luck with your 300ZX!
Nice build, I use a gps speedo on a boat they work really well and has a nice classic analog display i’d consider this.
Thanks! A boat seems like a perfect place to use GPS for speed: open skies for a clear signal, and less drastic speed changes (compared to a car, anyway). That makes a lot of sense.
11:00 you can use a small stepper motor, are small and you will be able to have great control. Use a shield with that ardunio.
Thanks -- I think that's what Speedbox is doing, too. I'm going to see if I can hunt down some small ones that can run at the right speed to get the speedometer to 85 MPH (or 130 MPH for the aftermarket speedometers). The next trick will be how to actually mate the speedometer cable to the motor. I'm not sure where you actually buy those connectors, and I worry that 3D-printed parts may not last long enough. It's definitely something I want to go back to, though.
@@joeangellx there is another aproach also, to move the spedo with a "voltmeter" like in modern cars and increment the mileage with a small rellay every mile in order not to be annoyng, like the thing that is counting the number of coins or similar :) i love the car and i cand help, not a master but enough to find a way for this issue :)
It can be done like a replacement, not to damage the original gauge, with the collor and the needle right chosed.
Right, sorry, I wasn’t clear: there is a short cable that runs from the speedometer to the Lambda counter near the pedals. That would be a perfect place to put the motor. It’s more figuring out how to attach that existing cable to the motor. I need some kind of connector - basically, whatever they call the female end that’s mounted on the Lambda counter that I can add to my motor box. I haven’t found the magic search terms to locate those yet, though.
@@joeangellx this will be the best/fast aproach, you have many thing to do beside this, but in case that also the gauge will broke, it can be done. The hard part was that sensor and to mitigate the errors.
When Alfa went to their transaxle layout they found long speedo cable from back to front caused problems. So they used an electronic drive on the gearbox - simple hall effect pulse that installed into original cable drive. This ran speedo in dash (so volt meter or motor?). Renault gearbox would have had a speedo drive? So maybe Alfa parts could get speedo working off gearbox?
Oddly enough, the DeLorean's automatic (a Renault itself) has an unused white wire that provides a sine wave that varies with speed. It would be pretty simple to add a diode and comparator to get a pulse that can be read by a microcontroller. I don't think the manual (also a Renault) has this facility, which is why they did the mechanical thing off the front left wheel, although I think there is a mechanical take-off on the manual. But then you'd have different systems for automatic vs. manual, so they just did something else entirely, I guess.
I would like to build something to drive the original speedometer. I know things like Speedbox exist, but I'd like to build one myself just to do it. The trick is finding a suitable stepper motor, and a fitting for the existing speedometer cable that runs from the Lambda counter near the pedals to the speedometer.
I have a mechanic friend who's into Alfas; I'll have to see if he knows of any parts that might work.
I like the videos. It does seem to show that for all the hype when the DeLorean came out it, in retrospect, is a bit of clunker. I’m sure it has its charm but …
I give it some slack because it was the first car from a new car company. Compared to the '72 Charger in my garage, the DeLorean feels downright futuristic and much more like a modern car, even though it's only 9 years newer. It had a lot of innovations, but it had a lot of problems, too. I feel like if DeLoream Motor Company had survied, later cars would have solved those problems, but we'll never know.
Have you tried pulse modulation? An example would be the climate control temperature knob in a '90s Chevrolet Cavalier. If the engine and radio are off but the ignition is on, turning the temperature knob will result in the electric motor to move the air blend door allowing more or less air to flow over the heater core. Those vehicles have no valve to stop the coolant from flowing over the heater core, thus the temperature is controlled by the volume of air flowing over the core. I hope this information helps solve this problem. As for GPS, I think Classic Instruments has a mechanical Speedometer controlled by GPS. Maybe it could be adapted to your problem. Check with other Companies in the Street Rod Community. Best Wishes with your cool car.
I originally stated looking into an angle drive alternative about 10 years ago, I think; my digital speedometer is only a couple years old, and I've learned even more since then. But when I first tried using an electric motor, I found that even with PWM I could only get it to turn at too high of a speed. Meaning, it would jump to 5 or 10 MPH or something like that from a stop, and I couldn't start it any slower. Later, I learned that you can get a motor to run slower if you start it at a slightly higher speed -- like, run for half a second at a 30% pulse width -- and then you can likely drop it back down to lower speed because of the inertia of the already-turning motor. I haven't gone back to it to see if I could get it to show slower speeds. Obviously someone has solved its problem, but it's one of those things that seems hard to search for.
I've also been wondering if a continuous rotation stepper motor could be used for this, but that might be the wrong application of a stepper motor. I've only used them in pre-built 3D printers, not in my own projects yet. There are so many easy-to-use motor control boards now that it probably would be simple enough to test one.
The GPS unit people in the DMC community seems to use is SpeedBox. I'll check out the one from Classic Instruments. They seem to have a lot of interesting products for interfacing with legacy systems. Thanks for letting me know about them!
The tire diameter is when the tire is not compressed by the weight of the vehicle.
That makes sense. It did give me a pretty good basis for my pulse counter, though - the speedometer is surprisingly accurate when compared to a GPS speed app on my phone.
I'm sure you're aware, Speedbox can run off VSS.
I've mostly heard about it being used with GPS, which is useful in DeLorean due to the lack of a native speed sensor, but I do recall hearing something about how Speedbox can support a VSS signal -- although I think it was after I made this video, and definitely after I built this speedometer, which was a few years ago now.
That said, I have some other projects that require a speed signal, and I intend to make changes to the instrument cluster itself, so directly driving the old speedometer is a short-term fix for me (which, I realize, I didn't explain in the video either). I hope to actually get to those other projects someday...
i feel like you should have swapped your original speedometer with a rev counter unit, and then drive that with the arduino setup. would have looked like factory, i guess.
also, gps is also a good idea. lag should not be a problem, as the speed app on your phone also uses gps to retrieve its values. it updates multiple times a second. you then could integrate your current solution with the value from gps to get a more stable/accurate reading.
I guess the question is how easy it is to find a pulse-counting speedometer that fits in the DeLorean's instrument cluster. It's not something I'm terribly familiar with -- I have no idea where I'd even start looking.
The main limitations of GPS are how long it takes to get the intiail lock and tunnels (not that I usually drive in any, but I"m outside Boston, and the Big Dig is a thing I go through occasionally). I've heard from people with Speedbox units that there is pretty decent delay after starting the car where the speedometer is getting a satelite lock, although I haven't seen one myself so I don't know what it's really like. But once you're moving, GPS should be just fine.
Mind you, I've driving without a working speedometer for at least a year, so it's not like the occasional GPS lock issue would really cause me any real problems.
The pulse counter just gets around all those by directly monitoring how fast the wheel is turning, rather than indirectly inferring the position of the car via GPS. It should be more accurate than GPS, since it can react more quickly to changes as well.
When driving at a constant speed, GPS and the pulse counter functionally identical to the driver.
Mind you, I do think that GPS is probably perfectly fine for this application. It just seemed a bit more complex for a DIY project as compared to counting some pulses.
I do have more involved plans that require some kind of digital speed reading. This is one of my earlier Arduino projects was a good test of how to make something work in a car, but it's still relatively primitive comapred to some of the stuff I'm working on now. I just need to find some more time to actually work on the new design.
@@joeangellx i did not want to talk you out of your solution, it is totally fine. i just wanted to suggest integrating gps data additionally to what already is there. there are some esp modules that already have gps on board, so you could just switch that arduino for one of those, use the same code and get gps basically for free.
for the rev counter to use, i thought of just a regular dmc rev counter, like your car already has one. you then would have two rev counters, but one showing the speed, if that makes any sense...
i guess you can just apply an appropriate pwm signal and bobs your uncle.
@@miko007 Ah, I see. Adding GPS to supplement the pulse counter certainly does seem reasonable.
As for the gauge, I'm guessing that you suggest I use a second tachometer for the speedometer? I just took a look and it seems that the tachometer module also has the low beam light indicator and right turn signal indicator, although it may be possible to transfer the same lights and wiring from the speedometer. Not entirely sure. Also, you'd lose the odometer (not that it works with my external display anyway). It's an interesting idea, though. Honestly, if I could find a way to convert the stock speedoemter to a rev counter and have the odometer work I'd do that just for the novelty of it.
@@joeangellx yeah right, second rev counter as speedometer.
you could also look into driving the actual speedometer using a small stepper motor, that would keep you the odometer at least.
another idea would be to use one of these cheap voltage gauges and somehow put its needle in front of the stock speedometer panel, but afaik there is not exactly an "axle" on those things, i have to tear one apart some time to see myself.
@@miko007 I have been looking into the stepper motor idea as well. The trick there is figuring out to actually conenct the existing speedometer cable from the old Lambda counter to the stepper. I'm not actually sure where you get those connectors from, and I'm not sure a 3D printed adaptor would be reliable enough. I feel like driving the stepepr shoudl be fairly simple, though, and it could mount right where the old Lamdba counter was.
Repurposing a voltmeter as the needle on the speedometer is an intereseting idea and probably worth investigating further as well. It would be nice to have a working odometer, though.
Please, how to make Km/h? 🤔
I should add that to the code. It's just a matter of multiplying by 1.609344 before displaying it.
At some point I plan on making a new version of the speedometer with more options, an odometer, and a few other features, but I haven't had time to do it yet.
@@joeangellx Great work, thanks!🙂👍
I would rather had used the Speedhut GPS Speedbox that replaces the box under the dash.
Seems a bit messy your setup.
I would go for GPS speedometer if it had not be for The Norwegian Public Roads Administration do not approve GPS speedo in cars.
I agree that mine isn’t as elegant as it could be. It’s more a prototype for a more involved project that wouldn’t work with a Speedbox, but I do think that Speedbox is a good solution for people who just want something that works. I also don’t like the lag from GPS, but Speedbox supports a pulse generator similar to my Hall sensor setup if you want quicker updates.
I am looking into a way to hook a stepper motor up to the speedometer cable from the Lambda counter to drive the speedometer. Then the stock speedometer and odometer would work, and it would be a lot cheaper than a Speedbox. But mostly it’s that I want to build the project the way I want, while for other people just want a working speedometer, and Speedbox is a good solution there.
Why do people say "speedometer" instead of "Tachometer"?
It's a very strange combination of Latin and English.
Tachometer is already used for the gauge that displays engine RPMs, so I guess they wanted to use a different world to cut down on confusion.
@joeangellx That makes sense