Speedometer!

Hi! I am developing an speedometer and I have some doubts about how to connect the reed switch to the wheel. I've thought to put the circuit with an Resistor and the reed switch fixed and the magnet connected to one radius of the wheel. But I have doubts about the reliability in wiring the circuit to the Arduino. Has anyone any idea? Thanks!!

We can only guess to what type of vehicle and wheel is involved, but for bicycles the magnet attaches to a spoke and the reed switch unit to the frame. A N.O. reed switch behaves like a push button, seems you have the right general idea - why do you think reliability is an issue?

0V ----[resistor 10K] ----- Arduino Pin ----------- +5V

Connect the Arduino pin to pin 2 or 3 to get an interrupt

A similar project was recently discussed, have a look at - http://arduino.cc/forum/index.php/topic,128147.0.html -

Thanks!
What I meant is different. I know how to connect the reed switch to the Arduino, but I am talking about the reliabilty of my connections when I have all connected in my bike.
I have the following elements:

But I have all mounted on a protoboard. I want to develop two different devices:

  • The final element - sensor-, which consists of one reed switch and one resistor. → Develop a Board?
  • The Arduino and LCD to processing and visualizing data. -->Develop a Board?

Both will be connected via cables…But I am not sure about the reliability of the cables… Because they are very thin…

So…What do you suggest?

Thanks Again!

So...What do you suggest?

Is it more a prototype project or a commercial one?

Duct tape (?) seems to work for many prototyping projects

I would not design a board for the reed sensor and the resistor, although if you do you could add holes in it to fasten it easily on the bike.

Many thanks Rob! I've designed a small board which has a reed switch + resistor + one female header - 3 pins: VCC, GND, Vout-. Yes, it isn't more than a prototype, at first... The duct tape could be a good idea in order to put it into the fork, but why holes? Some additional questions: - Where could I find a cable with I can insert the other three -VCC, GND, Vout-? Maybe if you are interested I could send you the .fzz file...by email. Thanks again! Anton

Depending on the size of the tire don't expect this to work above 50-60 MPH. At that speed the reed relay will start floating.

Depending on the size of the tire don't expect this to work above 50-60 MPH. At that speed the reed relay will start floating.

Judging by the speed you are predalling at, Lance Armstrongs doctor has already found a new job.

Duane B

super!