seanauff / classic-car-sensor-interface Goto Github PK

I know it's been months, but I finally got some adorable little hp bubble displays with SPI backpacks and was going to take a crack at building/modifying one of these for my own classic car. Do you have any board designs or code that you'd be willing to publish that isn't already up here?

Looking at the "Tachometer filter circuit"...
Not knowing anything about H11LMS optocouplers and I can't find that exact model in the diagram, which on the ones at Jameco site will work?

https://www.jameco.com/shop/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&search_type=mfgr&freeText=**H11L*

H11L1M ?
H11L2M ?
H11L3M ?
Thanks for the help.
Greg

Hi,

I came across your project on Reddit ... unfortunately that thread is archived so not possible to post there so hopeing you see this to answer my question.

Your circuit to interface the Arduino/Tinsey to the ignition coil looks simple and efficient so I built the circuit and it works with a signal generator very well

++ output of generator wired to TACH_SIGNAL
-- output of generator wired to GND

However, i'm confused as to how its actually wired to a ignition coil since most classic cars pulse the negative side of the coil from the dizzy ...

But looking at the direction of the diodes it looks like the TACHO_SIGNAL on your circuit is designed to to be wired to a positive pulsed input ?

Surely the + side of the ignition coil is just a static +12 supply ? so i don't understand how you physically wired the circuit to the cars ignition system.

Would really appreciate if you could expand on this a bit more on this and clarify exactly how to wire it to a car so that a Arduino/Tinsey can be used as a Tacho ..

One other observation .... in you circuit diagram you have the GND signals of the input and the output
of the opto-isolator connected together .. surely this negates the whole point of using a opto isolator (or at least part of it) if any large voltage or spike hit the GND side of the car it could damage the Arduino/Tinsey even worse if you had a PC connected then it could also fry its USB port or worse ?

Would this slight modification to your circuit offer better opto isolation ?

Many Thanks in advance
Cheers
Jay

Hello

I am currently building a dashboard for my hotrod. I have a good deal of my code already written, and it seems you and I were thinking very alike when we started out. I hope you don't mind, but I am going to pinch one or two lines of your code as there are parts that are much more elegent than mine, especially your rev counter!

I'm wondering, what car did you write this for?

If you are interested, mine is called Bad Juju the Volksrod, the briefest of google searches brings up a host of pictures though none are very recent (I stopped updating my build threads some time ago).

Anyway, thank you for sharing your code, it has been really helpful!