Since I'm not currently taking classes and have some free time to kill, I've decided to design a simple turn indicator for the eBike I'm soon to buy. I have some experience in designing an electronic system for my school's robotics club, but most of what I did was simply making the circuit in Altium; my team lead did the higher-level design.
I have decided on the following requirements for the system:
Requirements:
To power the system, I'm thinking about using a 9V battery. That way I can step down the voltage and not worry about the battery's voltage curve going too low.
In order to make the blinkers visible in daylight, I'm thinking about using 10 or so for each blinker, so 40 in total (plus 2 on the remote so I don't leave my blinkers on like a fool ). Assuming ~20 ma for each LED, that's at least 840 ma of current, plus whatever the other components will use. I'm not sure if a standard 9V can support that. If it can't, or if that would kill the battery very quickly, I could use some suggestions for batteries.
To control the frequency of the blinking I'm thinking about using a 555 timer. Since the timer can't have ~840 ma of current running through it, I'll use a photocoupler to isolate the timer from the indicators. This also protects the circuit in case the blinkers short out (likely, given the abundance of water in Florida).
In my experience with Arduino circuits, tactile pushbutton switches run into an issue known as 'bounce', so I'll have to implement a debouncing circuit lest my blinkers rapidly switch on and off when I press the button.
To regulate the voltage, I did some research and it looks like a zener diode is a good option. If the battery voltage drops too low, the zener diode should prevent the circuit from receiving inadequate voltage.
I'll need to find waterproof connectors for connecting the blinkers to the remote. I know I'll never make it 100% waterproof, but it needs to withstand the rain.
Finally, I'll need some sort of fuse. I don't think a physical fuse is necessary for this low a current, but I'm not sure what else to use.
That about sums it up. Is my circuit missing any crucial parts? I know there will be additional components per the datasheets for the timer and whatnot, but if I'm missing anything big, please let me know.
Thanks!
I have decided on the following requirements for the system:
Requirements:
- On/off switch
- Two signal buttons; one for left, one for right
- 50% duty cycle on lights, with ~370 ms period
- High-contrast indicators easily visible in daylight
- Front and back indicators
- Waterproof remote and indicators
- Ability to unplug indicators from remote
- Easily removable from bike
To power the system, I'm thinking about using a 9V battery. That way I can step down the voltage and not worry about the battery's voltage curve going too low.
In order to make the blinkers visible in daylight, I'm thinking about using 10 or so for each blinker, so 40 in total (plus 2 on the remote so I don't leave my blinkers on like a fool ). Assuming ~20 ma for each LED, that's at least 840 ma of current, plus whatever the other components will use. I'm not sure if a standard 9V can support that. If it can't, or if that would kill the battery very quickly, I could use some suggestions for batteries.
To control the frequency of the blinking I'm thinking about using a 555 timer. Since the timer can't have ~840 ma of current running through it, I'll use a photocoupler to isolate the timer from the indicators. This also protects the circuit in case the blinkers short out (likely, given the abundance of water in Florida).
In my experience with Arduino circuits, tactile pushbutton switches run into an issue known as 'bounce', so I'll have to implement a debouncing circuit lest my blinkers rapidly switch on and off when I press the button.
To regulate the voltage, I did some research and it looks like a zener diode is a good option. If the battery voltage drops too low, the zener diode should prevent the circuit from receiving inadequate voltage.
I'll need to find waterproof connectors for connecting the blinkers to the remote. I know I'll never make it 100% waterproof, but it needs to withstand the rain.
Finally, I'll need some sort of fuse. I don't think a physical fuse is necessary for this low a current, but I'm not sure what else to use.
That about sums it up. Is my circuit missing any crucial parts? I know there will be additional components per the datasheets for the timer and whatnot, but if I'm missing anything big, please let me know.
Thanks!