LED Indicators for bike schematic

Hello. I am making a project which is Arduino operated bike indicators. I have drawn out the schematic and i am just asking if you can check it over for any anomalies with the circuit diagram. If you cannot read or see what i have drawn then ask me and i will tell you in text form. I am using 6V battery pack and an Arduino Uno for this project.

I cannot see it on my iPad.
Attach a jpg or png image to your next post.

Hopefully this should work by using a file attach. If it doesn’t then tell me.

Would you go over the lines with a darker pencil/pen and rotate the image 90' ccw?

Here is a newer version with darker lines.

You have no current limiting resistors on the LEDs.
Placing LEDs in parallel is not going to work very well.
Always limit the o/p current of an Arduino pin to max of 20ma.

Should I use 500 Ohm or higher to protect the LED’S and for the diodes should i use a standard rectifier diode (1N4004) or fast switching?
I see your point in the parallel config and I will re arrange the position.
Is it wise to use the bike frame as ground for this circuit as I originally planned?

I cannot read what is connected to L or R.
IMO, I would use GND wire.
What kind of bike?
I normally use 220R for most LEDs at 5v power supply, but, that depends on the colour and brightness of each led.
1N4004 is ok.

I have a mountain bike with no suspension.
The part you can't seem to read is "To trailer" for when i get a cargo trailer.
The LED'S are bright orange so light isn't going to be a problem.

I think you are going to be taxing the maximum current that a pin can provide.
I'll draw up a drawing and post you my suggestions for changes.

Before I do this, are you using any other pins on the Arduino?

Is it OK with you to switch the ground in this application instead of the supply?
How are you powering the Arduino?
How many LEDS will be on the trailer?

Edit:
See attached image in the PDF

Yes it is ok to switch the ground in this application.One question: is Q2 a darlington pair and if so where can i buy it?
The arduino is going to be powered by a 9V battery and there will be 1 LED for the L part of the trailer and 1 for the R.
The switch you have wired is supposed to cut off signal and turn off power in the diagram. For the hazzard lights is it best to have an illuminated button especially during night.
Is it also wise to add a buzzer to know its working (when towing/ riding)?

TIP120 is a quite easily purchased, google TIP120 or you could use the IRL540 MOS FET and use the optional part of the drawing.

For the hazzard lights is it best to have an illuminated button especially during night.
Is it also wise to add a buzzer to know its working (when towing/ riding)?

It's your design go crazy with it. Have fun.

Hi, are you using the arduino for any other use, or is it just providing a pulse for the LEDs.
If this is its only function, then it is a waste of a controller, you could easily use a LM555 in 50% duty cycle mode, it will happily run on 6Volts and be a lot smaller.
Its almost as though you want to use an arduino straight out of the box, with the blink program already loaded, to be a blinker unit.

Tom..... :slight_smile:

Hi Tom. Yes it is to provide a pulse but i was planning to add a battery voltage indicator based on analogRead() function with a analog voltmeter with 0-10 postive range. Plus i tried a monostable 555 circuit but the LED just lit constantly with no pulse. I found arduino easier to manipulate than changing capacitors and so forth but thanks for the suggestion.

And Larry. With the MOSFET does it need that zener diode i can see on its gate pin? Aslo if i was driving a buzzer and iluminated button would it draw more current from the pin than it can provide?

Kind Regards
MrFarad

Also the arduino i have is uno which i could attach a proto shield to and solder from there but if i bought a nano would that be a much better option than going for a big stocky arduino board?

And Larry. With the MOSFET does it need that zener diode i can see on its gate pin? Aslo if i was driving a buzzer and iluminated button would it draw more current from the pin than it can provide?

  • The diode is internal, and part the the transistor. It is between the drain and source.
    The MOSFET would be a better choice IMO as there is less loss across it.
  • If you use an illuminated button, I assume it is on all the time (when power switch is on) so the pin will not be sourcing current thru it. Please explain how you would wire it up?
  • Also how would you wire the buzzer in your circuit?

I don't have a nano but do use Arduino Pro Micros.
They need a FTDI to program them or you can use your UNO as a ICSP.
If it was me, I would use a Micro.
They are a bit small and you would need a carrier card, for me it isn't an issue as I make my own PCBs.

I would wire the buzzer through a dual optocoupler and have the iluminated button run of the arduino pulse. what i would aslo like to control is a dipping system with led's mounted on a servo and control it with a toggle PTM. The only worry is if the toggle switch LED is going to draw a lot of current.

I'm not visualizing it very we'll, draw a schematic what you propose.
If the Arduino cannot supply/source enough current then a transistor is always an option.