Anybody have tachometer or speedometer?

**ACCLR8N** · 09-15-2009, 08:14 PM

I'd like to hear from some people that have succeeded in producing a tachometer or speedometer with the FB. My searches have yielded attempts and I hope they just never bothered to post their sucesses. Looking for some confidence I'm not wasting my time on these two points.

**RonS** · 09-17-2009, 07:25 AM

This what I have on the bench. Not a very good video but it will give you and idea. I have both tach and speed on the same source.

http://s255.photobucket.com/albums/h...t=100_1905.flv

**ACCLR8N** · 09-17-2009, 11:11 PM

Your engine sounds like a conure.

**Bugbyte** · 09-18-2009, 08:15 AM

Do you mean how would you build a tach/speedo mechanically or in software?

**RonS** · 09-18-2009, 09:18 AM

Really the engine is a couple of cockatiels..

**ACCLR8N** · 09-18-2009, 09:59 AM

Originally Posted by Bugbyte

Do you mean how would you build a tach/speedo mechanically or in software?

Neither, I'm specifically looking for individuals that have successfully used a Fusion Brain to display RPM and Speed from a running car. Lot of people talked about doing it. I'm having issues getting stable believable results. Capacitor decoupling at the FB inputs and power input made some improvements last night, getting close with the Tach. Engine cooling fans on are still throwing it off 0.15V. Speed still a mess...

**Bugbyte** · 09-18-2009, 10:46 PM

Okay, I've never used a fusion brain to do this but in 1986 I got speed from my car by using an infrared LED emitter and detector to bounce light off of the speedo housing (which was U shaped) as it turned. A friend built a digital circuit to count the number of times the housing went by and we queried the circuit to get the number and made the speed calculation based on the time that went by.

Surely the FB can count the number of times something turns -perhaps from a Hall effect sensor and then do the math?

**trader007** · 09-19-2009, 12:36 AM

Originally Posted by Bugbyte

Okay, I've never used a fusion brain to do this but in 1986 I got speed from my car by using an infrared LED emitter and detector to bounce light off of the speedo housing (which was U shaped) as it turned. A friend built a digital circuit to count the number of times the housing went by and we queried the circuit to get the number and made the speed calculation based on the time that went by.

even for today that is pretty ****in cool. for you to do that back then, i have a little manlove for you.

**Bugbyte** · 09-19-2009, 09:38 AM

I'll only partially hijack this thread with the actual circuit as this is mildly relevant. The diagram shows at the bottom the LED emitter and detector. The rest of the circuit is the actual counting stuff.

Don't they have magnetic sensors you could put on an axle that could feed counts into the FB?

**trader007** · 09-19-2009, 11:06 AM

Originally Posted by Bugbyte

Don't they have magnetic sensors you could put on an axle that could feed counts into the FB?

yes, on anti-lock brake cars... but most axles do come with the teeth on them, and many times a simple hole to drill in the hub allows for placement of the magnet sensor if you dont have abs.