RF Smart Bike Light

Projects General Guidance
1

I am a NYC bike rider who stupidly decides not to use my hands to indicate to others where I am turning. That being said, safety comes first and I ought to find some way to have turn signals, and I might as well turn this into a DIY project.

My plan is to mount the transmitter on the steering wheel and the receiving lights somewhere on the seat or frame. I will use an arduino mini/micro (or whatever other Greek synonyms for "small" they have out there) as the brains of the operation, and either the RFM69HCW Wireless Transceiver - 915MHz, the RFM69HCW Wireless Transceiver - 434MHz, or some other RF transceiver/receiver+transmitter system.

At this point of my planning I ran into my first (but relatively minor) question: what is the performance difference between the frequencies of various RF systems? I get that Hz is the measurement of frequency which is inversely correlated to the wavelength of a wave. However, does frequency correspond to speed, accuracy, or reliability?

My second minor question is whether or not I would need an arduino for each individual module of this light system? For my case I am only using two (one for the remote + one for the light) although I might try to upgrade the system to add a module to measure speed/cadence/etc...

Finally, my most IMPORTANT question is how in the world I power this stuff. I get that for the module that actually powers the lights, I might have to have a recharging power mechanism so I will probably use a small capacity NiMH or Li-ion battery. However, I would really like to only power the remote module through some sort of coin cell or potentially a single AA/AAA. Of course, for you guys to be any help, you have to know exactly what I am powering. For the remote, It would only be the transceiver, arduino mini, 4–6 buttons, and 2-3 LEDs (small ones).

Okay, that wraps up my questions.
Thanks in advance for taking a look and posing any solutions :slight_smile:

2

On a bicycle, it doesn't make much sense to use radios, because they are complicated and can be unreliable.

Wires are neither complicated, nor unreliable.

In any case, you should progress in steps. Get the lighting/signalling system to work first with buttons and wires. Then, you can replace the wires with radios.

You could even start with something like this.

3

Hi ghostbusters.

A good idea for DIY project.
You want to start with thinking what you want to do on the bike and break it down into sections.

Say left and right blinkers, brake light, speed sensor, travel distance per trip, day, week and total.
Ability to send data to your computer via WIFI or GSM.
Bike theft alarm and tracker.

The possibilities are endless.

For the small distance covered over your bike, wireless may be a bit of an overkill and may be prone to interference and woukd constitute a large portion of power to use with the micro.
Running everything from one power source is the easy way and since you will need wires for this, wires to the lights is easy.

A small battery being charged by a bike generator (use to have them running on the wheels to run a 6 volt headlight globe when i was a kid) would probably not need external charging from another power source.

With a small oled display on the handle bars could be good. Every kid on the block will want one.

Daz

4

You will have interference in NYC prob. RF makes no sense if you care about being sensible about making battery last. Your bike already has managed to operate its rear brakes without resorting to using RF, you can probably take notes from that system.

I would advise going pure analog circuit. No need for MCU. They make flasher relays. Should be a very simple job.