Electronic Experts and F1 Fans

[marcovandevelde]

Hi,
As an alternative: I've used one of these tachs for some time, really simple with a crocodile clip on one of the plugleads, has its own power and switches on and off automatically. Not expensive and often seen on minimotos. But no leds unfortunately.

http://www.gpt.it/power%20rpm%20english.htm

Greetz, Marco.

[Anonymous]

Swanny, how about two or three of these next to one another:

http://www.ledtronics.com/ds/CBG1500/

Looks like LedTronics has plenty of other options too:

http://www.led.net/datasheets/PCB_picture_index/PCB_picIndex.htm

I like the idea of about 30 or so LEDs in a line, maybe for a total length of around 4-5 inches, for the visual effect of the bar screaming across the display matching the howl of the exhaust. I admit though that the digit display is more precise; having both I think is an excellent idea.

Ok, I was looking at those also. The circular ones are really nice. The problem with them for a tach or speedo is that they are small, and worse yet, only have 15 segments. If you wanted a 10k RPM tach and only had 15 segments, then each segment would represent 667 RPM. This is too granular.

They could be used for other functions however.

For the tach you need, as you say, quite a few segments. If you use 30 for the same tack, then the resolution is 333 RPM. This is better. Each 10 segment display is about an inch long. So 30 sements is only 3 inchs of display. Without an analog guage you may want to increase the resolution.

However, since my plan is to scrap my whole stock panel I would like to use the digit display for my oil temp and fuel gauge; make a completely digital minimalist display.

Could I make the array from individual LEDs?

Honestly, I stole the idea straight off of the F1. Shhh!

Sure, you can do it with individual led's. The only issue is how compact can you put them in a display. Remember, you need quite a few for good resolution.

One other thing to consider. LED's wash out in sunlight. You need some that do not do this.

[richardhaggarty]

I took srivett2's advice and ordered up some samples of both the IC chips and the LED bars. The LED datasheets say they come in "direct sunlight" format as well as for indoor use.

What I need is help designing the PCB for the components.

[Anonymous]

I took srivett2's advice and ordered up some samples of both the IC chips and the LED bars. The LED datasheets say they come in "direct sunlight" format as well as for indoor use.

What I need is help designing the PCB for the components.

I was going to say that you needed to design the panel - how you want it to look, resolution of the display, what functions you want, etc, as the first step. Without knowing every detail of the display you cannot build anything. The electronics are all based on that.

[Anonymous]

I took srivett2's advice and ordered up some samples of both the IC chips and the LED bars. The LED datasheets say they come in "direct sunlight" format as well as for indoor use.

What I need is help designing the PCB for the components.

I forgot to address the PCB part. Most layout programs that I know off require a Spice based netlist to begin with. This means you need a schematic based simulation program, or enter the netlist by hand. Even after you get the layout, it's going to be costly to have the pcb fabed. This approach makes a lot of sence if you are going to production as the per unit price drops dramatically. If you are building one-off's or prototypes, most electronics design houses just wire them up by hand.

Some of the companies I worked for in the past had machines to cut double sided pcb's for prototype work. If you had access to something like this then you would be ok. I don't know how much it would cost to have something like that done.

You are thinking of one of the last steps. You need to get step one done first.

[Anonymous]

If you're building your own cockpit and if your bike has a gear indicator then you can create a new one using three triple input "or" gates on a 4075 coupled up to a 4511 driver driving a single digit display.

I've been toying with the idea of creating a custom instrument cluster for a while, I've just not come across something suitable for the housing. It may well be if we can get some workable designs for the electronics we can get together and get housings milled from billet (or some other method) and share the design and setup costs!

[Anonymous]

As for the logic behind the tach, I think using an onboard crystal and counting the number of clocks between the ignition pulses. The RPM would then be inversely related to this figure. It would be extreemly accurate also. Much more so than the display using bar graphs.

Yes, if enough get together the costs would be minimized. I have to stress again that the panel needs to be designed first. Not necessarilly the layout, but what is included and how the information will be displayed.