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blaze8978
10-06-2005, 07:57 PM
What will i need in order to make a led tachometer with a microcontroller
blaze8978
10-06-2005, 07:57 PM
What will i need in order to make a led tachometer with a microcontroller
Agent4573
10-06-2005, 10:24 PM
depends on what your ecu uses for a tach output. if your ECU puts out an analog signal, you'll need to run an A/D converter(which some microcontrollers have built in), then you just need to program it correctly. If you already have a digital signal for the tach then i would assume you only need the microcontroller and your LEDs.
Chris Boyden
10-07-2005, 09:03 AM
National semiconductor http://www.national.com
makes a really cool dot/bar display driver for LED bar graphs or custom LED displays.
You can do floating dot displays or bar graph displays, or have the dot track and dwell on the max rpm with rpm shown with the bar etc..etc...
You can also set it up with an alarm condition where the whole display will flash, i.e. shift light at a frequency(rpm) you choose with a dial or whatever.

LM3915 Dot/display driver (http://www.national.com/pf/LM/LM3915.html)

A frequency to voltage converter chip would be useful for converting TACH signals from the ECU into a voltage that can drive the display chip.
the f to V chip may also make interfacing to a micro's A to D alot easier.

the LM2907 is a TACH interface chip. You can use it for points, distributors, ECU's basically any tach signal. It also has applications for a TCS system.

http://cache.national.com/ds/LM/LM2907.pdf

This stuff may help, unless you want to program micro's more than you want to build circuits.
erny
10-09-2005, 04:51 PM
Hi

what microcontroller would you like to use and/or what would you like to use as the language?
Igor
10-10-2005, 12:32 AM
If going the microcontroller way I would choose a standard 8bit processor with a big fanbase to get support if you get stuck, preferably something you already have experience with. I would recommend Atmel AVR and Microchip PIC.
Programming them in C would be the most time efficient.

However, having done all this before with the whole fancy-display-on-a-CAN-bus, I would advice you to think hard about whether this is worth the time. It looks really cool and is a lot of fun to do, but as most ECU's can drive an analog rpm gauge and a shift light there isn't a whole lot of added value. Drivers don't have time to look down that much anyway.
So make sure you're doing it for the right reasons.

Igor
former spark boy