Updating a 1999 Saab with an Arduino

Unless your car is fresh off the lot, you’ve probably had the experience of riding in a newer car and seeing some feature or function that triggered a little pang of jealousy. It probably wasn’t enough for you to run out and sign yourself up for a new car loan (which is what the manufacturer was hoping for), but it was definitely something you wished your older model vehicle had. But why get jealous when you can get even?

[Saabman] wished his 1999 Saab 9-5 had the feature where a quick tap of the turn signal lever would trigger three blinks of the indicator. Realizing this was an electronic issue, he came up with a way to retrofit this function into his Saab by adding an Arduino Pro Micro to the vehicle’s DICE module.

The DICE (which stands for Dashboard Integrated Central Electronics) module controls many of the accessories in the vehicle, such as the lighting and wipers. In the case of the blinkers, it reads the state of the signal lever switches and turns the blinkers on and off as necessary. After poking around the DICE board, [Saabman] found that the 74HC151 multiplexer chip he was after: the state of the blinker switches could be read from pins 1 and 2, and he’d even be able to pull 5 V for the Arduino off of pin 16.

After prototyping the circuit on a breadboard, [Saabman] attached the Pro Micro to the top of the 74HC151 with some double sided tape and got to work on refining the software side of the project. The Arduino reads the state of the turn signal switches, and if they flick on momentarily it changes the pin from an input to an output and brings it high for three seconds. This makes the DICE module believe the driver is holding the turn lever, and will keep the blinkers going. A very elegant and unobtrusive way of solving the problem.

Hackers aren’t complete strangers to the garage; from printing hard to find parts to grafting in their favorite features from other car manufacturers, this slick Saab modification is in good company.

44 thoughts on “Updating a 1999 Saab with an Arduino

  1. Love retrofitting tech into my very base model car. (’09 Hyundai Accent GLS; w/ manual everything).
    Have been wanting to put an NFC enabled Bluetooth dongel under the dash, but I’ve been hesitant to pull out the paneling, so it just lives in my fuse box next to a Bluetooth OBD adapter. Turn on the car and Tasker launches Pandora and Torque, and I’m good to go.
    Other plans are after market automatic door locks.

      1. “distracted driving” aided & abetted by the marketing dept, causing the misguided masses to covet more and more frivolous tech that serves to draw away from the #1 responsibility of a driver – that of safely controlling that 2-3 ton piece of metal (that can easily kill other humans – intentionally, or un-intentionally).

        And let’s throw in the “aggressive driving” commercials (where some piece-of-$hit ‘family-sedan’) is operated by some knucklehead with low self esteem trying to compensate for something – driving ‘like-a-maniac’ (in an attempt to prove how “powerful” the piece-of-$hit family sedan is).

        We need to go back to the stone age of automobiles. Where radios were just chrome plated boxes with 2 knobs, a dial and 5 tabs sticking out, and if you wanted “entertainment” beyond that, you waited till you got home !

        (and I grew up in the 60’s “hot-rod” era, where ‘rat motors’ and 4 barrel Holly’s were weekend hacker projects). I look at the new C7 Corvettes and am disgusted by the fancy video game dashboard (even the new Lamborghini Aventador S fell into that trap). So I stick with my ’04 C5 Corvette, and C6 GS Corvette. No fancy distracted driving nonsense.

        It’s an abomination when new rental cars I drive have to be cycled thru 3-4 menu options to do something as simple as adjusting a blower fan ! (my daily driver, a ’07 Ford SUV, has a simple control knob to reach down and turn. done ! no dicking with menu’s)

          1. Yeah, keep thinking that – while the “millenial” runs into your family member/loved one, etc and kills them (or worse, makes them a quadriplegic), because they were distracted by the wiz – bang, fancy schmancy “entertainment system” on the vehicle. Happened to a friend of mine (his mother was killed by some 19 yr old girl driving “daddy’s” Lexus while trying to operate the entertainment system controls). Multiple lives destroyed – because of MP4’s and bluetooth.

          2. Dear NeoBlaBlaBla,

            In 2 years when the very youngest millennials are over 20 years old, can we finally stop conflating millennial and teenager?

            Signed,
            A 30 year old millennial with 15 years of driving experience

        1. The GS and bone stock vette got nothing on the 2018. Thanks for the rant but you sound like the Geico caveman. I suppose you’d be jealous of someone hacking a $220 FLIR camera to a heads up display to show roadside animals that could ruin a nice night drive. Tech is fine when used properly.

  2. I have that feature on my truck and I find it quite irritating and can’t figure out what it’s for. If they say lane changing that is hardly enough time to properly notify people of your intent.

    Overall great job though tracking all the signals down and making it happen.

      1. It was first introduced in Germany where it is called “Komfortblinker” (“comfort signal”). It is indeed for changing lanes on the mythical unspoiled-by-speed-limits German Autobahn. And it came about some 15 to 20 years ago, pretty much at the same time cars made the collective move to on-board computers.

        The “comfort” part is that you don’t have to fully engage the signal lever, and you don’t have to awkwardly keep holding it down half-engaged. People got too lazy and just didn’t signal at all.

    1. I agree. When I was home visiting my parents, I was using my fathers new Honda and it has that feature, and it kept messing with me. I just stopped using the directionals all together while I was there.

    2. In most countrys it is enough to make your intentions clear, but there is always the option to pull the lever to the on position and leave it there for a constant blinking too.

      Lane changes are a much smoother ting outside of the US, no need to start blinking and wait for someone letting you in, you blink 3 times as you change lane to the overtake lane, you overtake, you blink 3 times to get back in the right lane and everybody keeps happy

  3. I like how people won’t be fooled by sale tactics but act like driving a car older than ten years or even five years qualifies as a social stigma that only the most daring tempt..

    1. funny… but eventually that unpopular “old” car could become a classic and then who will be laughing?

      That social stigma you mention… where do you live exactly?
      The cars I drive were never younger then 12 years… does this mean that I’m not allowed in your neighborhood without being a social outcast? Ahhhh… now it all comes back to me again… the days in school where they bullied me because my shoes were of the wrong brand. Or the time I told someone which computer I had and the made fun of me saying that it was soooooo 8 bit… or the fact that I do appreciate Celine Dion or like the muppets. The fact that I rather watch children shows (like Gumball) instead of adult gameshow or action movie entertainment. Or that I rather watch scientific television shows or documentaries rather then the latest “pimp my house” show. Some people even accuse me of “not having a life” because I sit behind my computer all day (writing great programs and designing great hardware they never understand) while they (the social kind who do claim to have a life) hang on the couch swiping their phone or shop around in the mall wasting their time (doing nothing creative)… but they are oohhhhh sooooo social… Most of them never seem to realize that being social didn’t get the caveman out of the cave. It was the odd nerd who on his own created something new allowing progress to happen!

      And now YOU tell me that my car is too old?!?!?

      PS: I don’t consider myself one of “the most daring”… I just don’t care!

      1. Where I live doesn’t matter.. Drive a ’90 escort or similar anywhere near a new development, or pretty much anywhere at night.. Extremely likely you’ll get pulled, and even more likely you’ll get checked if you sit somewhere too long.. Most businesses will give you dirty looks and act suspicious..

        The anti-conformity posturing is cute and all, but I’d bet money your life almost lacks your internet-philosophy entirely..

  4. ODB was introduced much later in Europe. I drive a 1998′ car with a Motorola 68HC. It takes one and two byte Hex commands to read and set values. All kinds of disastrous hacks possible here, including flashing every part of the not protected ROM as long as the checksum checks out.

  5. How about a feature that “reminds” the driver with a friendly shock when they neglect to use their signal? Call it “training mode.”

    Just three blinks? Sounds like a dick feature. Signal-while-changing-lanes-and-not-a-second-before.

    But good job.

    1. In Australia the RoAd rules specify to indicate 3 seconds prior to changing lanes. All the cars I’ve driven with this function only blink 3 times which is not compliant. I do wonder how it is allowed form an ADR point of view.

  6. I want to use mannequin arms attached to my mirrors as turn signals.
    I wonder what the legality of that would be.
    It would definately fall under silly.
    I bet it would be fine as long as they didn’t stick out too far and your original turn signals worked.

  7. Nice job!

    If it was up to me, I would have put the Arduino between the DICE module and the signal lever, (sort of pass through) not inside the DICE module. What if the arduino decides to give up the ghost and wreak havoc inside the DICE module? If you need to remove or replace the Arduino, much more easier than to desolder and removing the double sided tape…,

    1. So… socket the Arduino on top of the 74HC151. It’s unlikely to fail and if it does probably won’t do anything at all… if your pass through version failed you’d have no blinker.

    2. By putting it in the DICE module saves either cutting wires or trying to find an obscure connector. It also makes it totally reversible.

      The original intention was to use one of those sot23 style6pin PICs and mount it in the same way.but after some discussion on the SAAB forum others pointed out they could duplicate easily it if it was an Arduino but using the PIC (especially one you could hardly see) made it too difficult.

      If the Arduino plays up worse case is it shorts the power rails and blows the internal 5v reg and kills the DICE. Other than that the IO pin could stay stuck in output mode and hold the blinker on or off. Or if it just shuts down then theblinkers would operate as normal. It’s only a couple of screws to get it out and it’s all back to original.

  8. You could honestly write a lot of articles on the SAAB hacking scene. Just find a copy of trionic5.pdf or trionic7.pdf for a peek. Sad that all the documentation on ecuproject.org seems to be gone forever. :(

  9. Why oh why would you intentionally implement the second most annoying feature on modern cars (the first being the complete waste of screen wash with the same hold-on function). Show me how to ***disable*** it without voiding warrently and I’d be impressed.

  10. This could have been done with a 555 timer from outside the module :P.

    I’m surprised how many people hate this feature. How often do you accidentally hit the turn signal stalk the wrong way? From my experience it works best when traveling at 55+ and you’re making a quick lane change and you already know you’re clear. The 3 blinks are just a pleasantry to the other drivers that you’re calling dibs on the lane.

    1. I just hate it when my car blinks three times when I, the master and leader of the whole operation, just want to blink once. Thats all.
      It’s absolutely impossible for me to buy a new car (although I could afford one) because I cannot tolerate the constant annoyance of those #$&%+&$-electronics. It starts with this stupid seatbelt warner. When I drive to work in the morning I drive about five hundred meters on our property before I have to open the gate to the street. It is MY DECISION and no other’s business if I fasten my seatbelt for these five hundred meters or not.
      Sorry for the long text but I hope you get my drift…

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