Tachometer mods

[mousewheels]

I am more of a visual guy myself. I have a hard time picture how to do something when some one puts it in word

What helps for me is read and annotate a diagram. Then wire connections are clear when looking at the actual wiring.

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Tach_Adapter_Connections_2.jpg (67.51 KiB) Viewed 5618 times

[Breezy]

Hey Mouse,

Thanks for your help and push in the right direction

Here is my small contribution, Just received the final piece of the puzzle today, hope to do some testing in the weekend

So I spent a whole weekend reading up on how to build this, most of the people that made this sort of hertz generator did not specify what kind of frequency range theirs had, and I think theirs were for other purposes, like running speakers, and they looked OTT for this job, so needed to get into the nitty gritty of it



I may post some pics and build data if needed

Looks like I can do some much better testing now, I think I may have gone wrong somewhere with the other means of testing, maybe a bad signal feed from the car?, or just my incompetence, I think just me ...



this is a little bit of an elaborate build, but it can be simplified into 1 potentiometer , 1 Resistor , 1 capacitor , 1 frequency panel meter , a 555 timer , a small circuit board , random wire (maybe total $25 NZD), If you are lucky to have a multimeter with inbuilt frequency/hertz read out built in it, it could cut this cost in half....

will post some more about this on this thread if wanted.....

Good Day....

[mousewheels]

Sure make a thread on your signal generator with frequency monitor. I think many here are up to more electrical work than they get on a scooter.

The 555 timer chip you used for a signal source is 41 years old, yet remains a very popular chip. Some sources say, there's been about 1 billion per year shipped (2003).

Looks good, glad you took time to build your calibrator

[gyromaniac]

Been a while since an update on progress with the suntach. Any news on what would be needed to make it work with the gyro?

[Breezy]

I found out where I went wrong, the lazyness of my gauge is on both sides
So more or less its linear, its just the first and last cm of sweep thats the problem, yea im a douche.....

[mousewheels]

Been a while since an update on progress with the suntach. Any news on what would be needed to make it work with the gyro?

Gyro mods are complete. Scroll back up the thread. We have 2 circuits which have been used with the Sun Tach. Second is the easiest to build, and can be make as a splice in mod.

-- PC Serial Port Calibrator --
A while back a tach calibrator was proposed using a serial port + 2 components. A companion file of zero's, and a terminal program were used to generate given RPM references. That approach has been converted to an application supporting 1cyl 2T, 4/6/8 cyl 4T scaling.

Calibrator_Control_Panel.jpg (81.15 KiB) Viewed 5547 times

-- More accurate analog tach + 10k/11k range --
Looking for a small more accurate tach a 'stepper tach' from Depo was found (Amazon/eBay and others have this model). Likely micro controller controlled, pointer angle is controlled by number of steps the motor is rotated.

Available in 10k and 11k RPM models it eliminates need for internal mods. One thing I'd do change next time: Get the clear lens version rather than 'smoked'. Smoked lens is not very bright in the sun.

The accuracy of this tach provides a good show with the PC based calibrator:

1500 RPM

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4000 RPM

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8000 RPM

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[mousewheels]

Back on page one of this thread:

Looking forward to how you plan to hook in the pickup on the engine. Some of the tachs I've seen use an inductive loop around the spark plug wire... as do timing lights.

Let's dig into those passive pickups - starting with a commercial tach, the Trial Tech.

Many of the 'wrap a wire' on the coil lead tachs implement a capacitive pickup rather than inductive. This means even a 'no turn' pickup should work. 'No turns' facilitates a 'clip on' sensor, convenient around the shop.

Here is an experiment run today, with good results. I will finish off the sensor by gluing the brass tube to the clothespin, then test further.

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