41 replies to this topic

[dklawson]

Congratulations and welcome back !!!

[stormintrooper]

yeah congrats on passing and lucky sod for exploring india lol

[Leykor]

Hi All...

Yes!! It’s been awhile. Truth be told finding time juggling work and play has been extremely difficult of late. None the less to catch you up, I've been working on a project of mine for quite some time and finally I can see myself nearing the end.

I have designed from scratch a Tachometer to be used for a mini (or any other vehicle) that is constructed from digital electronic components.

The focus of my design was not to include any micro-processor IC`s. The reason for this is that microprocessors need to be programmed by the constructor. My design uses fairly standard IC`s that can be soldered together and will work for anyone with very little electronics experience.

I am writing a manual which is a step by step guide to the design and construction of this tachometer.

I have three things left on my list
1) Design stable power supply
2) Design good input signal filter
3) Design PCB layout

I post now to remind people that I have not forgot and have been making slow (very slow) progress. I’m now on the home stretch so expect design info soon.

Here is an animated attempt of showing progress and how it should work...

 Tachometer4.gif   282.27K   15 downloads

 TachAnimation.gif   411.08K   13 downloads

Sincere Apologies
Leykor.

[Kerrin]

Looks Great.

something like that would be really easy to tie in to a custom dash install and would be a great acccessory to a Megajolt.

[mike.]

That does look really good - Well done!

I wish I could do electrics!

[TopGearRules]

WOW , thats brilliant I cant wait to see the plans for the custom tachometer.

Alex

[ukcooper]

Ive bought 2 or 3 off these from shops.

One thing to watch is how bright you have it, in day time you need it bright so you can see it but at night some units where to bright and burnt into your vision.

Second one is don't make it to sensitive as the numbers on tick over bounce up and down like mad.

Last point could they be made so the person could choose what colour they have to there match interior . might help sell them if you ever try.

My 10p worth

[Leykor]

Thanks ukcooper for the constructive advise, with regards to your concerns,

I have definitely made the brightness a concern and have included a photo resistor (LDR) to adjust the brightness depending on the light conditions. This allows for a bright display during the day and a dim display at night. The initial brightness is also configurable via a variable resistor.

This design is quite sensitive but also quite stable. . Only the last two digits "bounce" a bit, I will look into providing a jumper for people who just want these digits to stay at 0.

I do not intend on selling any units, I will provide a detailed report for the design and construction. This will enable you to build the tach to suit your needs. You could replace the back plate with a different colour or the digits with blue ones etc.

Thanks all for the acknowledgements

Regards,
Leykor

[rusty789]

I do not intend on selling any units, I will provide a detailed report for the design and construction.

That would be awesome so I could build one!!

[rusty789]

Any updates on this, i think it would be good as a college project!

[Leykor]

Hey Good People of TMF

You`ll be glad to know that I`ve sorted out the power supply completely and have done half the PCB design.

The circuit is pretty much complete, except I’m not too happy with my input signal filter. The input signal is taken from the coil -ve terminal. This signal is not very clean and is found to be riddled with voltage spikes and signal oscillations. Any suggestions would be appreciated; currently I’m just using a diode clamp, a zener overvoltage regulator and a low pass filter.

Regards,
Leykor

[JonnyBMX]

any updates on this?