L3wis said:
My first query: Could you possibly explain how the micro-controller would get the engine RPM and the Wheel spin? I have never used micro-controllers before.
Second: Where would I connect it?
Third: Is the setup described like a bike speedo. Where i attach a magnet thing to a spoke on my wheel rim?
I need help
hehe
I'm new to this too, so don't take anything I say as gospel or the best way to do this.
To get very basic, a microcontroller is like a small computer on a single chip. It allows digital (and sometimes analog) inputs. You can program it, like any computer, in assembly and sometimes C or BASIC, and output signals from it. The PIC, and Atmel lines are popular.
You can use two LM2907 chips which convert signal frequency to a voltage level, that's easily read by the microcontroller with an analog to digital input. If you do a google search you can find the lm2907 datasheet and application sheet, which does a good job of describing it's function, and how you might implement it.
One LM2907 would be used to convert the signal going to the ignitor or points system into an RPM signal (I assume the bike is not new enough to have a electronic ignition with crankshaft trigger inputs).
The other LM2907 could be used to determine wheel speed (or final output speed). The type of wheel speed sensor you use, is up to you. Like I said, you can pull these sensors out of late model cars at junkyards. The ABS ones are usually small incased sensors and trigger wheels. The Honda ones I work with have a 5volt input, ground, and signal output. You just have to find some way of turning the trigger wheel.
Your microntroller would be programmed to read these two inputs and you can decide on an output type. LEDs that light up on gear position, LCD display that actually displays RPM and gear, anything you can figure out. My own Tacho that I'm working on for my racecar will be using an RC servo controlled by the microcontroller to turn an indicator needle and reproduce an analog RPM gauge.
With the microcontroller you can also implement other features pretty easily, like an over rev warning indicator. Read other sensors like temperature sensors, and even do some type of security start, or anti-theft system.