Everyone who owns a bicycle must always practice safety on the road, may he/she be a cycling enthusiast or just someone who commutes to school or work with a bike. A full gear, or at least a helmet, must be worn at all times in order to protect one’s self from a crash. Most of the riders have a smartphone and unfortunately, a large number of them use their phones while riding the bike.
Albeit not scrolling, but rather listening to music with a set of earphones attached to their ears. It is just a disaster waiting to happen. Majority of young riders also don’t practice traffic rules and safety by switching lanes anytime they want without checking. To make use of the technology to our advantage, let us design a simple prototype: a turn signal attached to a helmet that is controllable with an Android app.
Step 1: Plan the materials to be used
There could be several ways to connect your phone, either wired or wireless, to an LED controller. So the first step is to gather whatever you have or what is readily available and then the design will just follow. In our case, what we have laying around in our junk box is an HC-06 Bluetooth module and a PIC microcontroller.
And so obviously we will be interfacing with our phone via Bluetooth. Also at this stage, picture ahead how the lights will sit on the helmet together with the electronics. Aesthetics may not be a priority here but the weight and the looks will definitely add to the overall functionality.
Step 2: Design the controller
The circuit is very simple, just a couple of connections from the LED driver through a GPIO and from the Bluetooth module through serial to the microcontroller. The first design uses 4 AA batteries and an LDO voltage regulator. But in the future, these will be replaced with Li-Ion batts and a switcher to give it more juice and efficiency.
Step 3: Fit everything in an enclosure
Luckily we have a spare enclosure which could fit all the batteries and the PCB inside it. A cheap bicycle blinker sits nicely on top of it too. Shown below is its assembly.
We don’t need the LEDs and its circuitry inside the blinker anymore so we have to remove it and replace it with several LEDs arranged as arrows for turning left and right. Then finally connect their wires to the microcontroller inside the enclosure.
Step 4: Develop the app and the firmware
We do not own the softwares used in this build but was rather developed by students who bought the materials from us. We only developed the hardware. You may download it here:
Step 5: Test it and enjoy!
Yah, you’ve read it correctly. Test it and enjoy!
Wrapping it up
So in conclusion, this project is really fun to build plus it works great for its simplicity. It can signal for turning, for hazard, or just have all the LEDs illuminated. The phone can also be easily attached to a handlebar mount. Just don’t forget to set the display timeout to at least 30 mins or longer so you won’t have to reset the lock screen every time you want to tap on it.
So what do you guys think? Feel free to share your thoughts with us down in the comments section below.