Animated Bluetooth Bike Turn Signals

Tired of risking his life every time he had to signal a turn using his hands while riding his bicycle in rainy Vancouver, [Simon Wong] decided he needed something a bit higher tech. But rather than buy something off the shelf, he decided to make it into his first serious Arduino project. Given the final results and the laundry list of features, we’d say he really knocked this one out of the park. If this is him getting started, we’re very keen to see where he goes from here.

So what makes these turn signals so special? Well for one, he wanted to make it so nobody would try to steal his setup. He wanted the main signal to be easily removable so he could take it inside, and the controls to be so well-integrated into the bike that they wouldn’t be obvious. In the end he managed to stuff a battery pack, Arduino Nano, and an HC-05 module inside the handlebars; with just a switch protruding from the very end to hint that everything wasn’t stock.

On the other side, a ATMEGA328P microcontroller along with another HC-05 drives two 8×8 LED matrices with MAX7219 controllers. Everything is powered by a 18650 lithium-ion battery with a 134N3P module to bring it up to 5 VDC. To make the device easily removable, as well as keep the elements out, all the hardware is enclosed in a commercial waterproof case. As a final touch, [Simon] added a Qi wireless charging receiver to the mix so he could just pull the signal off and drop it on a charging pad without needing to open it up.

It’s been some time since we’ve seen a bike turn signal build, so it’s nice to see one done with a bit more modern hardware. But the real question: will he be donning a lighted helmet for added safety?


40 thoughts on “Animated Bluetooth Bike Turn Signals

  1. There’s a reason why car turn signals are simple, orange blinking lights. Typical car driver won’t concentrate on some tiny, fancy arrows because there’s a lot of other things that might happen on the road.

    1. Indeed. The correct turn signals for a narrow vehicle stick out as far as possible. That is why the “legal” bicycle hand signal for a right turn, in some US states, with the left hand raised, is both useless and impossible. The logically correct signal is to stick out the RIGHT hand.

      This invention is not useless, but I feel that it would be improved if it were far wider.

      We do usability testing for other products. How about testing cyclist’s turn indicators?

      1. Wide signals are quite hard to do on a bike though. Most of the time it’s not a wide object. I have however seen cyclists attaching translucent plastic tubes to their bikes (sort of like whiskers) then putting LED strips in those. They make you look wider on the road so people passing tend to give you more space, but they could also be useful here as the ends could house indicators or if they were RGB strips you could turn the ends orange.

        Something like this:

    2. I also prefer blinking lights, but does a car driver really need much concentration for this?
      The straight up arrows are a bit confusing though, it’s not a standard and you can’t be sure what it means.

      Incidentally you can buy very similar setups ready-made on the Chinese sites, if anybody is interested but doesn’t want to build it.

      1. “I also prefer blinking lights, but does a car driver really need much concentration for this?”

        As a commuter/distance cyclist, my observation is that being able to distract them away from their phones as they drive would be the biggest asset of all. Perhaps we can resurrect the (illegal) concept of portable digital quiet zones.:

        1. The darkening glasses to blank out TVs are a nice idea. Although consider the sound of a TV more intrusive – especially as this nefarious devices play commercials nearly all the time. But against this the TV-be-gone type remote control power-off scanners are a good thing.

          BUT I would consider any RF jammer intruding into my personal space as REALLY UNACCEPTABLY INTRUSIVE. There can only be one solution against such a device: seek-and-destroy, let the thing go BANG, convert it to molten slag, with not too much worry about collateral damage to it’s owner/carrier.

          You can decide for your own digital quietness: Switch off YOUR digital devices as often you want. But leave other people alone.

      2. The thing with blinking lights is that you see them with the corner of your eye and you’re still fully aware of them without any attention shift. With animated miniature displays you have to shift your attention from broad picture (driving) to very small picture (examining tiny displays). And in traffic that can be very dangerous.

  2. Awesome! I do get nervous seeing “UltraFire” lithium cells in potentially-sunlit enclosures and/or places that might be subjected to lots of mechanical stress, especially when they’re operating at low discharge rates and using charger/protectors that probably don’t cut off until 2.5-2.8V, but it looks great and I like the variety of ways to control it!

    1. It’s no problem to have a cutoff voltage of 2,5 to 2,7V in a single cell device. No reverse charge can occur.

      Recharging a cell damaged by reverse charge would be a danger. Because then you could have copper plating in the separator. Then if you manage to charge the cell with high current, you can store a substantial amount of energy in it which dissipates in the separator, leading to thermal runaway.

      Therefore any useful charger charges a deeply discharged cell (<2V or 2,5V) with a very low "conditioning current". If the cell takes charge at a low rate, it is undamaged and you can increase to normal charge currents as soon you are over 2,7V or 3V. If it does not take charge at the low current, it will not reach this limit and you have to discard it.

      For the cycle lifetime of a cell such extreme voltage levels are of course bad. For the longevity of the cell it would be best to use it only between 3V and 4V (or 4,1V). As especially the high voltages are responsible for aging of the cell.

      1. This is why I’ve always been surprised that I don’t see charging circuits with a “long life” option, that knocks back the top voltage a little bit. It doesn’t even cost you that much capacity!

  3. So I really dislike people who just bash others’ projects without contributing anything useful, and I hope that my comments are not interpreted as such.

    However, the lights as shown appear to be a) not large enough for visibility from a distance (it relies on seeing the triangle animation) and b) not bright enough for visibility in daytime, and c) use confusing signage (what does the up arrow mean? The bike is about to take off?).

    As a cyclist, I would not trust my life to these lights. I would much rather (and do) take a hand off the handlebars and use standard hand signals.

  4. I think for better viewability from vehicles I would just have an arrow with a large blinking head pointing left or right, rather than an animation. Better yet would be to make it blink amber, but that would take hardware changes.
    Otherwise, seems like a pretty decent setup. :)

    1. I think the bigger issue, (as a fellow Vancouver rider) has always been people turning across bike lanes without looking. Not sure what we can do about that one though.

  5. Bad idea.
    I absolutely HATE everything that blinks on a road and I want to punch cyclists in the face for their blinking tail- and front light.
    It robs my vision at night because I can’t CLEARLY see the distance and speed I’m travelling at.
    Remember the good old Strobe lights in discos? They make everything look frozen. Same with your little blinking light. I can’t sense the speed you and I are travelling.
    Same goes for this little thing.
    Stop making it complicated and blinking / animated and stuff. KISS – Keep it small and simple!

    Why does every cyclist try to invent something new?
    A bycicle is a manual motorbike. So use the same conventions. Slap a license plate on it because it participates in regular traffic. Make every bike have a PROPER headlight that doesn’t blind everybody that is in front of it, make it have a STATIC backlight, BRAKE-light And a shitty blinker on each side of the bike extruding about 30cm so everybody has enough room for that.
    Same like a motorcycle.
    DONE. No need for shit inventions, blinky stuff and annoying, pesky distractions in traffic.

    /rant off.

    Sorry its nice as a project and all – but it drives me mad that people on a bike THINK they are allowed to do everything they want. A cyclist is a participant in traffic and cars, scooters, bikes and trucks have to obey state laws when participating. But a cyclist is allowed to do whatever he wants?

    1. Sorry to annoy you. But a regular bicycle non-blinky tail light is but invisible in the evening mess of street lights, and even less so when it’s wet. That’s why they tend to be in blink mode.

      1. I understand that. But again – what would happen if I turn off my taillights for 2 seconds and switch them back on again?
        I would be invisible to every other car for that time period and scare the crap out of everybody around me because they don’t know my location.
        Why not use both? I have seen taillights that are static bright but have a less bright blinking element to them to make you aware of the presence. Which is okayish. The blinding bright taillight in blinking mode is the main issue here. No car has direct LEDs facing straight back. THey are usually diffused and broken up so you have proper “glow” but no direct bright blinding light. This is an issue for people.
        There is a “moth effect” going on that drags you as a car driver towards that blinking light because you heavily focus on that to properly analyze it’s speed and distance.

        But then again – there HAS to be another solution than just flashing stuff. Again – make it obvious and mandatory for every bike to have the same regulations. Give them brake-lights aswell so you see what they do.
        Police would stop me dead on the road if I would drive around with flashing LCDs and LEDs in my rear window facing strait onto people’s eyes. But as a cyclist it’s okay to effectively blind people?

        1. I’m a bit skeptical about blinding capabilities of most of the bike tail lights. Compared to car lights, they just don’t have enough juice to be that bright and they are not exactly focused like lasers.

          As for your suggestion for part full-on, part blinking, this exists. My taillight is actually exactly like that. I’m not sure which if the lights is brighter though, I’d guess the dimmer one is full-on, otherwise the battery wouldn’t last long.

          1. It’s not about permanently blinding you. But do yourself a favor – go out at night with a friend. Grab a flashlight. Tell him to shine it perpendicular to the road – now you stand back from him about 50 meters.
            Now you tell me if that’s blinding to you or not.
            ANY lightsource that is moderately bright is blinding you, if the light hits your eyes directly. This is the reason why all modern cars (Xenon, LED) are equipped with auto-leveling sensors that must limit the height automatically.
            Same should go for every bycicle. Turn your headlamps down to the road and not into my face – you don’t need to see that. Same goes for the taillights. Why are LEDs facing straight back instead of being sideways and getting diffused and redirected? Because it’s cheap. And this is bad. But allowed. And this is my gripe with the whole situation.

          2. “they are not exactly focused like lasers” for most (but not all) tail lights this is true, but for modern bicycle head lamps literally laser focus is the norm not the exception. i got to see one of these bikes with blinding front light turn and *DAMN* even 30 degrees off axis it *COMPLETELY DISAPPEARED*. stunning.

            but nothing is as hard to see as a blinking light. you want to get the attention of motorists but it doesn’t work for that, and you simply cannot tell which way a blinking light is moving.

        2. I use a pair of one static and one (less bright) flashing light on the front and back of my bike. I find when I’m in my car if I see a flashing light I will expect it to be a bicycle and can know to reduce speed farther back.
          I have to say, I mostly try cycle off of main roadways to avoid playing with heavy and fast traffic, but even on the canal paths there are cyclists with incredibly bright lights aimed right in my face such that I can’t even see the path in front of me anymore, I have to stop to avoid crashing into them or crashing into the water or the hedge. They don’t even slow down, or say thank you, or acknowledge me in any way.

          1. Thank you.
            And this is my main issue with that topic.
            It’s not that cyclists shouldn’t be allowed or something like that.
            The LEDs are just aimed like shit in every direction.
            But wohoo wait for the shitstorm to hit if I drive around with my adaptive LED lights and High beams on at night. It just blinds you in terms of the night vision you have. Sure – LEDs are small comapred to a car headlight – but the issue remains that DIRECT light into your eyes is really bad for your night vision and thus it robs you of precious seconds that might be life saving.

            I know that part blink part full exists. But is has to become the standard when I purchase a bike. Screw that mentality:
            Here’s your bike, go on a shopping spree and buy the blinkiest and crappiest shit you can get.
            I don’t buy a car or motorbike without head- and taillights, do I?
            Why is a bycicle allowed to be sold like that?
            And don’t come with the argument of race-bikes that need the extra savings in weight. They need special permits to allow that. So a regular bycicle / mountainbike has to come with that stuff from the factory. With PROPER lighting and not a cheap chinese blinking light that flashes every 5 seconds “to conserve batteries”. These times are long gone in the modern era of proper batteries and LED.

    2. Yes cyclists are sometimes quite schizophrenic:
      On the one hand the want to be considered as part of normal traffic when it is about rights.
      On the other hand they behave like they know a bike is a sports device or toy (*), when it is about duties or obeying rules.
      *) What is true, but then they can not require any rights in street traffic. Have license plates and proper lighting, then ask for any rights.

      1. It’s probably that ‘cyclists’ are no more a single group than are ‘motorists’. Also, at least in my region (UK), cyclists don’t have to ask for rights, they have rights. What they find themselves having to do is assert their rights. I don’t think it’s reasonable to put license plates on bicycles. Theft of bicycles and pieces of bicycles is already high. It’ll surely be trivial for someone intending not to heed the law to travel without a plate or to steal the plates of another.

    3. Bikes are a weird thing. In the law system, depending on country, they are defined as participants of the road…when and only when they’re on the road. And not, when not. Not to mention all the by-laws that change those definitions area by area. However, even if you use the argument “well where I live there is no grey zone” which is a valid one probably, those who enforce would-be laws to cyclists give a lot of leeway. Many cyclists are deathly afraid (with good reason) of driving on the roads because automotorists are so god damned terrible themselves. We all know the rules we break when driving, and how often if a cyclist happened to come around the corner when we did what we did they’d be dead. I can understand the annoyance of blinky things, too bright lights, etc but cars do the same bullshit. Halogens never came to where-ever you’re from?

      1. I hear you.
        Halogens are annoying where I live. Many people have cheaper chinese headlamps installed for new looks and such and no one cares to properly align them. They blind everything.
        And then I’m sitting in my car with adaptive LED lights and getting flashed at when my adaptive high beams turn down the second the sensor recognizes a light and the driver cannot possibly be blinded by that (tested that with a friend of mine extensively). So yeah – I know what you mean.
        Cars, bikes, scooters – all have their flaws. But as a regular owner of a vehicle that must be registered and properly to regulations, I am immediately punished when I drive around with – let’s say blue interior lights or stuff like that.
        But a Motorbike- or Bycicle-owner can basically do whatever he wants – because “they are hard to get hold of”. Reason? No plates (Motorcycles only have rear plates and thus are next to impossible to properly track).

        We all share the same road, the same towns, country and direction of travel. Why make different rules for that? No reason.

    4. “Sorry its nice as a project and all – but it drives me mad that people on a bike THINK they are allowed to do everything they want. A cyclist is a participant in traffic and cars, scooters, bikes and trucks have to obey state laws when participating. But a cyclist is allowed to do whatever he wants?”

      I think you have touched on the root of the problem with out knowing it. I am a cyclist who obeys all of the rules of the road (including constant on tail and headlight as required by law in my location) but the problem is that everyone seems to think that its all of us against all of them. The problem is that both groups have their assholes and those people should never be used to indicate what the rest of the group is like. I have had drivers come with in inches of my handle bars when the law is that they are supposed to give me a meter, and then they flip me off because i am going top slow. Or in areas where i have had too many people get to close to me i just take the entire lane (which is also legal and encouraged for safety because not every road has bike lanes) and then i have people who are absolutly abusive to me about it. That being said, most drivers are incredibly nice and give me lots of room so i will never assume that all drivers are like the dicks that intentionally try to frighten me or get all worked up because waiting to pass me made them 2 minutes late for what ever super important event they were rushing to. Then there is the mentality issue too, it sure is nice to be in a car with a safety structure wrapped around you while i am on my bicycle with nothing to protect me and no where else to ride (sidewalks are meant for pedestrians and where i live you cannot ride on them if you are over 16 or have a tire size over a certain diameter)

      What i am trying to say is that i know that sometimes cyclists can be frustrating because they dont seem to know or appreciate the rules (and common sense) of being on the road but the same can be said of alot of drivers and from a cyclists perspective that can be a much scarier proposition. I guess what im trying to say is that we should all be a bit more tolerant of other people and have a think about what the other people are going through before we are so quick to judge and lay blame.

      As for another thing i have seen mentioned: bicycles are sold with out lights because it is actually the minority of them that are sold which are ridden on the roads. the majority of bicycles sold are ridden off road and during the day only, parks, tracks, trails, etc, etc. It makes more sense to sell the lights separately from a business competition stand point.

    1. Why does this device need a booster anyway? Red LEDs need 2V forward voltage and most CPUs work at 3V also if not straight from the 1980ies. The ATMEGA328P works from 1,8V to 5,5V.
      Bluetooth modules work with 3V or less, some even regulate down to 1,8V internally.
      Only the MAX7219 requires >4V so it is a bad choice for this project. The TLC59xx (TLC5940, TLC5947, etc) LED driver chips work with a single lithium cell.

  6. Interesting. I just checked our local laws for turnsignals on bicycles. They can be legal, but there are rules that need to be followed. The most important rule seems to be the color that has to be yellow for a turn signal, and not red!
    And since there seems to be some discussion about blinking lights on bicycles as well, here in Switzerland it is clearly defined that you need a static light in the front and back. You can however add blinking lights to that static light for better visibility. If you use blinking turn signals, the rest of the lights have to be static tho.

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