Life Blinker is an open source project from Sigma-Designs

Build your own Life Blinker using the DIY guide and
My Open Source code on github.
For a product overview, see the Life Blinker intro video.
If you enjoy schematics, see the PDF drawings .

Let’s face it, the first thing you thought when you saw the bicyclist above was probably, “is she waving at someone?”. But ignorance of hand signals for motorists and riders is not a trivial matter. Neither is taking your visibility for granted. Bicycling has inherent dangers!

Tragedy struck my small beach community at dusk August 7th 2022, when a bicyclist was fatally wounded by a motorist in an intersection. This crash was one of two collisions that killed bicyclists in Carlsbad in August alone. The southern-California city declared a state of emergency, citing a 3.3x increase in bicycle crashes — from 30 in 2019 to 100 in 2021. However, this problem is hardly local.

According to one study, 52 percent of bicyclist feel unsafe to ride in their locality. Yet, in the countries like Denmark, Sweden, and Netherlands up to 45 percent percent of local transportation is done via bicycling. Historically, significant fractions of populations around the world, particularly in Asia, have used cycling for transportation. Imagine if renowned violin maker Haide Lin was struck in his childhood during his 30-mile ride to violin class. I think we could all agree that the world could give a big break to the environmentally friendly cyclist.

I decided to make a difference by designing a DIY flasher and signal light. This device is sourced from globally available parts, so people in developing nations will not be missed by far more expensive products only available from companies like Amazon. My open source Life Blinker Project uses rechargeable batteries, keeping re-occurring costs (and environmental impact) to the absolute minimum. This project is so streamlined, that you don’t even need a printed circuit board (DIY from cardboard or sheet plastic). And the code works on any 2-3 dollar arduino mini. (I actually learned arduino c-code concepts from an online friend hailing from South Africa, talk about ubiquity!).

Many things about this project are small; the cost, the size, the effort. The results however, could make a big difference, for one person at a time.

I got the wifi control code working perfectly. Now, the blinker v1.3 can light up from a remote switch. By coincidence, it was very helpful and just in time for my 75-year old Grandma's surgery. We repurposed the Life Blinker into a call-for-help button. Nana was able to get help in the guest room from anyone in the living room. Her candy dish full of Hershey white chocolate peppermint kisses was excellent motivation for being a first-responder.

Nana liked the Life Blinker so much, she took it home as a Christmas gift for my great-grandma who is almost 100 years old. It’s been a very affordable and versatile attention getter. For what started out as a bike safety tool, this device is now helping several senior citizens with their quality of life. I made six in an hour and will be offering them to families with older dependents in their homes. I hope many more uses for Life Blinker arise for people of all ages, worldwide.

Makers Journal, January 2024, update:

After a long wait, some motion sensors have arrived. The analog ADXL335 and digital MPU-6050 (TDK based chipset) arrived and the showdown began. Both devices are MEMS-based, but whatever is inside the ADXL335 got stuck on tabletop testing. Essentially, the Y axis stopped providing a useful signal range in a very short period of time. I will move foward with code for the MPU-6050. This sensor will allow an "auto brake" indicator, and maybe a fun game idea I've been obssessed with.

Makers Journal, March 2024, update:

For much of 2024, I have been working on improving a stop sign based Life-Blinker device. The Life-Blinker Full-Stop is powered with solar panels. Testing with various COTS TP4056 series charging pcbs has been challenging on a variety of levels. Initially, I had diffuclty sourcing a reliable solar panel to feed the pcb and batteries. While finding a usable 10W 6V panel, I made many controlled run-time tests and was preferring the TP4056. However, if rainy or dark weather prevails long enough, boards like the J5019 have a better mechanism of providing drained batteries sufficient charge level before giving power to the microcontroller once the sun is back. I'm still working on finding a circuit with higher efficiency and touchless power management for this last scenario, though the solution may be an output diode in addition to the input diode already in use.