Building a shift light

Russ

Russ

Club Member
Hi,

I'm too tight to spend £100+ on a shift light box of trickery for my motorbike (this project could of course work on your car) when I know the components are only about £5.

So I'm going to make my own, but apart from some soldering experience I'm no electronics guru.

Here's what I've found so far. I got Electronics Workbench 9 so I can design the wiring on my pc and *hopefully* perfect it there (haha).

Anyway the brains of the operation will be this baby...

http://www.national.com/pf/LM/LM2917.html

Here are some diagrams for some application ideas
http://www.national.com/an/AN/AN-162.pdf

A frequency to voltage converter, seems widely used and about £1.80 from RS (http://rswww.com).

Heres a few things I've found on the subject...

911 forum, bit of discussion
http://forums.pelicanparts.com/showthread.php?threadid=226183&perpage=20&pagenumber=1

Shiftlight wiring diagram (linked from 911 forum)
http://innoves.com/pmaehling/20050817_ShiftLight.pdf

Guy designing his own shift light
http://www.electro-tech-online.com/...reviews/11034-lm2907-shift-lamp-problems.html

Bar graph shift light
http://www.horrible.demon.co.uk/bikes/led_rev_counter.htm
and wiring diagram for it
http://members.tripod.com/~foz11/DIY_MOD_s/Digital_Speedo/digital_speedo.html

I'm looking to do a MSD style shift light (think five red leds in a pod), not one of the bargraph type, pot to set the RPM. This little chip has the potential to do a lot of nice little things, nice little project for my lunch breaks :)
 
This brings back memories. Back in the early '80s I built a digital dashboard as part of my HNC.....still got it in a box somewhere. It had digital and analog speedo and rev counter and analog fuel, temp, oil, and volts. I used the Lm3914's to driver most of the bar graph led's with only a simple circuit on the front of it. I'll see if I can find what box its in (we're between homes at the mo so everything is in boxes).
 
Grolls: This is for my motorbike, too busy looking at the horizon to know the revs when I'm draggin ;)
 
Russ said:
Grolls: This is for my motorbike, too busy looking at the horizon to know the revs when I'm draggin ;)
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ya wont sell that old crap to me mate, you have to feel the force mate ;)

ps, sort the airbox,ecu,gearing,exhaust,rear shock,adjustable steering damper, harris rearsets and get a quick shift and say bye bye to the hairdressers on gixers and r1's!:D







.
 
Shift lights look pretty. Not sure they are a very good substitute for listening to the engine though...

I'd use a PIC to keep the component count down. if the output from the sensor is good enough you may get away with connecting it (near) directly, or to an A/D input.
 
grolls said:
ya wont sell that old crap to me mate, you have to feel the force mate ;)
Click to expand...

Well honestly the only way I know I'm at 10k is when the engine 'feels' like it wants to self destruct. Been chasing my brother on the motorway and there's little feel (I think) at those speeds, too busy watching the road.

grolls said:
ps, sort the airbox,ecu,gearing,exhaust,rear shock,adjustable steering damper, harris rearsets and get a quick shift and say bye bye to the hairdressers on gixers and r1's!:D
Click to expand...

Done a BMC filter but intend to open up the airbox some (saw it on the net somewhere). ECU, nothing yet, kinda like the fuel glitch at 3krpm. Gearing, lost a tooth on the front sprocket. Exhaust, Yoshimura RS3s. All suspension and damper redone by GPR or someone (never heard of them). Harris rearsets, that's for hairdressers ;) Quite fancy a quick shift although I reckon I could make one.

Anyway this "no substitute for listening", of course there is! The thing tells you exactly what rpm your doing, no potential for human error there. My head being above the screen makes my TL slower accelerating than my bros GSXR750, so I'm all tucked in, nice big light would be great!

spyro said:
I'd use a PIC to keep the component count down. if the output from the sensor is good enough you may get away with connecting it (near) directly, or to an A/D input.
Click to expand...

I'm a programmer by trade, but still prefer the other route. I think for purely a shift light this route tidly made in a little ABS box would be better, plus this will cost me a fiver ;) If I were doing lots of things from my tacho output then the PIC route would probably prove tidier yes.
 
johnymd said:
This brings back memories. Back in the early '80s I built a digital dashboard as part of my HNC.....still got it in a box somewhere. It had digital and analog speedo and rev counter and analog fuel, temp, oil, and volts. I used the Lm3914's to driver most of the bar graph led's with only a simple circuit on the front of it. I'll see if I can find what box its in (we're between homes at the mo so everything is in boxes).
Click to expand...

Very OLD SKOOL Johny :D, I want to see this! Please dig it up and post a picture. Knight Industries 2000 would be proud. :D
 
Russ said:
Done a BMC filter but intend to open up the airbox some (saw it on the net somewhere). ECU, nothing yet, kinda like the fuel glitch at 3krpm. Gearing, lost a tooth on the front sprocket. Exhaust, Yoshimura RS3s. All suspension and damper redone by GPR or someone (never heard of them). Harris rearsets, that's for hairdressers ;) Quite fancy a quick shift although I reckon I could make one.
Click to expand...


Remove the airbox and take the flapper assembly out. Then grind away all the rubbish hindering the aiflow, you will see what I mean when its removed, (free )use a K&N and get an early ECU (£100). =flat spot gone and it will pull much harder and be more responsive when exiting corners. Want more then go to TLR cams giving 1mm of extra lift, whilst its in bits, remove all cam quietning gears (will sound like a Duke) then gas flow n skim and then on the dyno you will have to run +30% on fueling providing you use the front Yoshi pipes. mine ran 140bhp@90ft lbs at the rear with more to come.160 brake is not a problem, ya bum and ya wallet are.
 
My poor TL is doomed after reading that :D Thanks for the info!! I'll let you know how I get on (after the Z of course) :)
 
Oh and found out my shift light chip (LM2917) is 15v... Wonder what voltage you get on a bike when it's running?? Will check when I'm home.
 
SKiddell said:
Russ

You have what amounts to a trigger waveform from the tach pulse from the distributor or the coil current sink

How about an F to V converter (LM2907) gets your tach pulse or coil current pulse to a voltage then feed a comparator configured as a voltage detector, then output to a simple driver circuit to drive a ganged LED setup.., have a pot wired to the comparator to give you a threshold voltage as the frequency rises so does the voltage until it hits the setpoint and hey presto a variable shift light.
Click to expand...

So back into this then.

That's what I needed to read a book for, what I thought I wanted has a name, and it is called a comparator :) Thanks!

Now what I don't know is how you go about building that. I'll try to figure out some more later, but often I'll look up a circuit diagram and see there are various resistors included and I've no idea why (I know what a resistor does). I'll try to figure it out. I mean I do know why they are included but I think it's figuring out that I'd need one and what rating is where I'm getting lost :)
 
Oooh having just discovered the ability to read

The LM2907, LM2917 series are monolithic frequency to voltage converters with a high gain op amp/comparator designed to operate a relay, lamp, or other load when the input frequency reaches or exceeds a selected rate. The tachometer uses a charge pump technique and offers frequency doubling for low ripple, full input protection in two versions (LM2907-8, LM2917-8) and its output swings to ground for a zero frequency input.

The op amp/comparator is fully compatible with the tachometer and has a floating transistor as its output. This feature allows either a ground or supply referred load of up to 50 mA. The collector may be taken above VCC up to a maximum VCE of 28V.

The two basic configurations offered include an 8-pin device with a ground referenced tachometer input and an internal connection between the tachometer output and the op amp non-inverting input. This version is well suited for single speed or frequency switching or fully buffered frequency to voltage conversion applications.

The more versatile configurations provide differential tachometer input and uncommitted op amp inputs. With this version the tachometer input may be floated and the op amp becomes suitable for active filter conditioning of the tachometer output.

Both of these configurations are available with an active shunt regulator connected across the power leads. The regulator clamps the supply such that stable frequency to voltage and frequency to current operations are possible with any supply voltage and a suitable resistor.
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It has an op-amp (which I just figured out I could use) built in...
 
Russ said:
Oooh having just discovered the ability to read
It has an op-amp (which I just figured out I could use) built in...
Click to expand...



A Ham sarnie short, more like!:unsure:
 
Tell you what Russter, if I get chance either tomorrow or the weekend I will Russtle:D up a circuit diagram and then give you a call to go through how it all fits together and works...electronics at this level is dead good fun but there are some basic principles that need to be bottomed out first
 
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