I'm going 1JZ | Page 4 | The Z Club of Great Britain
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I'm going 1JZ

Discussion in 'Hybrid Z cars' started by Russell, Dec 28, 2016.

  1. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Hmmm - any chance of giving it a permanent +v feed without killing a car battery if laid up for say 3 weeks?
     
  2. Russell

    Russell
    Z Club Member

    That wouldn't achieve anything though?

    It finds its zero position quickly, just jitters a bit.
     
  3. Russell

    Russell
    Z Club Member

    Right! Just did a bit more searching online at everybody's favorite search engine. (apologies to the non technical for filling this part of the build thread with coding stuff)

    So the motor itself only has 315 degrees of rotation. Its Zero point essentially involves slamming itself into its stops to acknowledge it has turned as far as it can. Having looked at some other projects, some have the jitter more than others so need to look into the library I am using and see if there is a better approach to getting to this point less aggressively.
    The command on the library is simply Motor.zero(); so I need to understand how that works first.
     
  4. franky

    franky Well-Known Forum User

    All of my SPA and Stack tacho's do it on initial power. I like seeing it. Race car cool.
     
    AliK likes this.
  5. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    I was thinking it loses the zero point position data in volatile memory when the power goes off. So once it found the zero point, providing you don't power the controller down, then the position data is preserved a all you have to do is give it the sweep command when the ignition comes on.

    Having said all that, I see Franky's point and now thinking it's cool too ;)
     
  6. Russell

    Russell
    Z Club Member

    Found a way around it.

    The zero command simply turns the stepper motor anti clockwise it’s maximum steps. As it pretty much starts at zero it just bounces off its stop until it times out.

    I just remove the initial zero command as without speed input it zeros itself. Therefore it will always start at zero as long at I don’t turn the engine off when I’m rolling.

    Taking a similar approach with the tacho so will probably use a capacitor of some form that will keep it alive for long enough to reset to zero when the tacho input stops when it’s turned off. I could just keep the ignition on for a second or so before I turn it off but that isn’t good enough for me.


    Sent from my iPhone using Tapatalk
     
    AliK likes this.
  7. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Good man!!!

    I knew you'd find a way! And I love the capacitor solution, simple and effective!
     
  8. toopy

    toopy
    Z Club Member

    I have absolutely no idea what your talking about, but it looks good all the same, i quite like the jitter aspect on start up :thumbs:
     
  9. Russell

    Russell
    Z Club Member

    I like the sweep but the jitter was annoying. Worked out now though.

    Waiting for my second screen to arrive now so I can continue.


    Sent from my iPhone using Tapatalk
     
    AliK likes this.
  10. Russell

    Russell
    Z Club Member

    Still working on the speedo and as per my previous comments I wanted to incorporate as much as I possibly could into the original platform and have it feeling as OEM as possible.

    Well I have very nearly achieved it after a lot of work. Without getting too technical, the code is reasonably complicated and made harder as I’m trying to fit it all into an Arduino nano and then it has to fit into the original speedo without looking out of place.

    The reason for any of this is because I want the inside of the car to be as original as possible and the original speedo mechanical drive won’t work with the digital speed sensor in the new gearbox.

    I could just find the correct mechanical speed sensor from an early Supra, screw it in and be done with it but that seemed to difficult.
    Much easier to spend months designing, coding, experimenting, going back to the drawing board and generally banging my head on the table.

    Anyway, here is what it currently looks like
    [​IMG]

    The basic parts are;
    Arduino nano - for the non technical its a kind of mini computer that handles everything plugged into it.

    Speedo face - currently cardboard and behind it is a GM stepper motor.

    Small screen - This goes behind the main ODO and simply displays the cars mileage. Every time the handbrake is applied, it saves the mileage to the Arduino memory.

    Large screen - This goes behind the trip counter and displays all of the functions I have been working on. More on those shortly.

    Rotary encoder - This turns like a volume knob and presses to select “things”. This goes into the original trip reset location with the original knob so everything looks OEM. As well as resetting the trip, it is also the main input device.

    To the left is the Power supply (all runs at around 5v) and a frequency generator which allows me to simulate the input from the gearbox.

    [​IMG]
    Trip time in Minutes from when the engine was started

    [​IMG]
    Digital speed readout

    [​IMG]
    Trip counter which is reset by pressing to rotary encoder

    [​IMG]
    0-60 timer. Final bit of code I need to work out. It’s not quite right and I want it to be as automatic as possible. Just stop the car, nail it and it will tell you how quickly you got to 60mph

    [​IMG]0-100 timer. See above

    [​IMG] This is the rotary encoder

    [​IMG]
    This is the ODO

    Next steps are to get the 0-60 and 100 timer code working properly, design the final circuit, power supply and fit it all into the original speedo.

    Oh, and finish the rest of the car!

    If anyone happens to be an Arduino whizz and wants to help with the 0-60 timer, I would be eternally grateful!


    Sent from my iPhone using Tapatalk
     
    AliK likes this.
  11. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Just superb!! A supra mechanical fix wouldn't have been anywhere near as satisfying or fun!!!!

    Love the 0-60-100 timer, a clever add-on!
     
  12. Russell

    Russell
    Z Club Member

    Cheers, open to incorporating other ideas if people have them.

    Just need to get the event timing right so it starts, stops, displays timings, best time etc. All with only a tiny bit of memory left on the arduino.

    630 lines of code so far!
     
  13. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    Last edited: Jul 4, 2018
  14. Russell

    Russell
    Z Club Member

    I certainly can and no reason to use a new sensor as there is one in the gearbox.

    It will end up being much more accurate than any cable driven speedo.

    Here's how the Arduino knows how fast you are going;

    Eveytime the prop rotates, the speed sensor sends 4 pulses which are picked up by the Arduino.
    All I have to tell it is how many Pulses it should receive per mile - Worked out with a bit of Pi, diff ratios etc. and thats my figure. Takes 2 seconds to update and can take into account any combination or wheel size and diff ratio.
    The Arduino takes the Pulses per mile and calculates speed, distance traveled etc.
    I then use this information to drive the speedo needle and all of the other functions.

    For testing I simply have a frequency generator that sends out a square wave signal. I have a simple spreadsheet I put together which I input the speed I want and it tells me the frequency. This allows me to simulate whatever speed I want. I have taken it up to a few thousand MPH so far while I was making sure the mileage counted correctly and didn't want to wait too long.

    I have been trying to think of other useful functions and may add a 1/4 mile timer as well.

    If anyone has ideas for useful/fun functions, let me know. Essentially, if it can be calculated with Distance and Time, I can add it. There isn't enough memory or spare inputs to add other factors.
     
  15. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

  16. Russell

    Russell
    Z Club Member

  17. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    What about 1/4 mile runs!? You already have speed and odo readings so it shouldn't b a lot more code, right?

    And with segment splits too!?
     
  18. Russell

    Russell
    Z Club Member

    segment as in 1/4, 1/2, 1 mile?

    Top speed as well I guess
     
  19. Woody928

    Woody928
    Z Club Member
    Staff Member Moderator

    Looks very trick dude, seriously smart stuff there. How's the rest of the car progressing? ;)
     
  20. Russell

    Russell
    Z Club Member

    Yeah not as quick as I would like!
     

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