Thread: digital speedometer

hi, im new to this site. I was wondering is this IC is good for a proyect im thinking to make . This ic number is ICL7107 , here's is the site with the info on this chip: http://www.jameco.com/webapp/wcs/sto...roductId=43756


this chip includes :seven segment decoders, display drivers, a reference and a clock. I got interested in this chip cause the proyect i want to start in my car , the dash have limited space, and from what i read this chip have everything integrated to it. i just started thinking about this proyect, so i dont know the values of the analog speedometer of my car (97 eclipse). any info would be apreciated , thanks.

i got a signal from the tachometer and speedometer . Its a linear dc voltage as speed/rpm increases so does the voltage.maybe i can use that directly with an analog /digital converter and adjust it till i get rpm/mph...?

Madhouse-
Can you elaborate on what you did with the 34 segment driver chip? I would also like to use a pic chip to drive a 3 digit speedometer with 30-40 LED bargraph. I have the specs to do it with CMOS chips, but I wanted to make this project using some sort of PIC chip. Also, do you know of any examples of code I can look at for this kind of display? I would like to make a matching tachometer. Basically take a signal from a digital speed sensor, and make a fancy display for a custom dashboard.

Joe

Originally Posted by kn1ghtride

Madhouse-
Can you elaborate on what you did with the 34 segment driver chip? I would also like to use a pic chip to drive a 3 digit speedometer with 30-40 LED bargraph. I have the specs to do it with CMOS chips, but I wanted to make this project using some sort of PIC chip. Also, do you know of any examples of code I can look at for this kind of display? I would like to make a matching tachometer. Basically take a signal from a digital speed sensor, and make a fancy display for a custom dashboard.

Joe

4 shift registers or one LED driver would do it... the LED driver has the costs more but has internal current sources for the LEDs. Just clock out the pattern you want on the LEDs.

D.

Originally Posted by cadstarsucks

4 shift registers or one LED driver would do it... the LED driver has the costs more but has internal current sources for the LEDs. Just clock out the pattern you want on the LEDs.

D.

Can you reccomend an LED driver??? Microchip's list seems endless...
I might also like to make a couple separate rows of arrays that scale up and down. 12 segments in the array... It can't be that difficult!!!

Thanks for the input- Hopefully I won't be a newbie for long...

Joe

Originally Posted by audioguru

Cars stopped using digital speedometers in the 70's because the numbers are just a blur. Maybe you can gate the input so it jerks in a visible manner.

i get round this by only updating the display once every 200ms, and using a running average of the last 5 samples , lovely and steady

and i use the max7219 led driver btw

if i use a pic for this project i would need a voltage to freq converter so the pic accept this input? or could i use a analog to digital converter first and make the pic read the binary numbers? right now i have the microcontroller pic16f628A.

Originally Posted by victorcarlos

if i use a pic for this project i would need a voltage to freq converter so the pic accept this input? or could i use a analog to digital converter first and make the pic read the binary numbers? right now i have the microcontroller pic16f628A.

That will be a @@!!!!***
There are PIC microcontrollers with on chip A/D converters. Try out the PIC16f88 for (if you want pin for pin replacement) or PIC16f690 (my fave).

hi guys do you have a scemetic diagram of a pic based digital speedometer as well its program in microC? co'z im having difficulties on creating a pic based digital speedometer using a pic16f84a or pic16f877a...