by amandaghassaei instructables.com:
Monitor your road speed using the Arduino. This project uses a magnetic switch (also called a reed switch) to measure the speed of one of the bike’s wheels. The Arduino calculates the mph, and send this information out to the LCD screen on the handlebars as you ride. It is compatible with any kind of bike/wheel, simply enter the radius of the wheel in the firmware to calibrate the device for your setup.
Arduino Bike Speedometer – [Link]
Mike Chambers writes:
Here is how it works. I have an Arduino Duemilanove with ATMega328 which has two photo-resistors connected (with a 10k pull down resistor). I set up two laser pointers to shine a laser directly onto the photo-resistor (which is enclosed within a dark box). The Arduino monitors the values returned from the light sensor, and watches for any changes that indicate that the laser bean has been broken. When both laser beams are broken, the Arduino calculates the amount of time between when each sensor was tripped. It then sends that value to the Adobe AIR based client, which is connected to the Arduino via USB / Serial port and a serial port proxy (in the case, TinkerProxy).
Arduino based speed detector with a Flash! – [Link]
The OBDuino is an in-car real-time display of various information, like speed, RPM, instant fuel consumption or average trip fuel consumption as well as others PIDs supported by the car. It reads the data from the car’s OBD-II connector, interfacing it via a MC33290 chip to the Arduino which processes the CAN data and outputs to a 2×16 LCD. [via]
OBDuino: car diagnostics with Arduino – [Link]
This project is a speed detector based on Arduino platform. Arduino is measuring the time it takes an object to travel between two points and transmit this data to a computer or smart phone where it is converted to speed value and presented in a clear way. Check more details on code on the site below. [via]
Arduino Based Speed Detector – [Link]
The 555 Ic is wired as an astable and the frequency is constant and independent of the duty cycle, as the total resistance (R charge + R discharge, notice the diode) is constant and equal to 22Kohm (givin a frequency of about 1Khz, notice the hum).
Simple DC motor PWM speed control – [Link]
This project is a variable speed control for the heater blower in a car. The heart of the circuit is a PIC12F675. PIC is reading the potentiometer value and generates appropriately timed pulses to control the DC motor. Check project details on the link below.
PWM Motor Control – [Link]
This project describes how to read the speed of a PC fan using Arduino board. It’s a good introduction to reading pulse duration and driving 7 segment led displays on Arduino. The text is written in Japanese but the link below will autotranslate to English. [via]
Reading a PC fan speed with Arduino – [Link]
This is a simple circuit for DC Motor speed control (fan speed control, light dimming and etc) using the 555 timer. Also a good starting point for novices wanting to get their hands dirty with the 555 timer IC. Some would argue that this is not the most efficient approach.
Simple and dirty PWM For Motor Speed Control – [Link]
This is the circuit which inputs the control voltage which was created by the turning of the motor in PIC. The input voltage to PIC is converted by A/D converter. Changed voltage is used for the PWM function of the CCP to control the motor drive. At the circuit this time, a small motor is used as the generator to detect the number of rotations of the motor. The input voltage (the control voltage) to PIC is changed by the fluctuation of the number of rotations of the motor. [via]
DC motor speed controller – [Link]
The BitESC is the smallest speed/motor controller I have come across. It is designed to work with the motors from those tiny R/C cars we all bought at least one of, but now never use. Well, here is you chance to make a really tiny R/C plane
The BitESC is a small electronic speed controller for those little RC cars like the MicroSizer / BitChar-G. It can be used in a small RC plane to have some control over the speed of the motor. The speed of the motor ramps up or down, depending on which of the buttons on the transmitter you press. [via]
Micro sized electronic speed controller – [Link]