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‘Westield build diary’ Category

  1. Partial success

    februari 12, 2012 by frank

    I got the speedo working with a PWM signal generated by a generic output from the Megasquirt.  I then send this signal through a PWM converter with a 32 multiplier.  This generates a 499Hz signal that indicates a speed of 18km/u, what corresponds with what I calculated.  It was kinda cool to see the odo ticking forward.  I let the car run for 8.8km :) .  The speedo should be spot on :) .
    Unfortunately, I didn’t get it working in the car yet.  My transmission generates an AC signal that I convert to a square wave and send to the PWM converter.  Although it works with my self generated signal, it doesn’t work with the signal coming out of my VR converter.  It looks ok on the oscilloscope though.  I’m a bit puzzled, but I’m sure I’ll figure it out eventually.

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  2. Speedo is working after all

    januari 29, 2012 by frank


    Decided to take another look at the speedo today.  Turns out I forgot to solder the wire for the VSS signal.  After soldering in that last wire, the speedo works.  It indicates 3 km/h when I’m doing 99 km/h, so my earlier calculations (32.5 times slow) seem to be correct.
    I haven’t yet built the VR circuit, but I plan to anyway, so I can remove the MX5 pcb and put it back into the MX5 cluster.

    Only thing left is to program the PIC16F628 to correct the signal.

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  3. Accidently deleted all pictures :(

    januari 23, 2012 by frank


    Did an update of a WordPress plugin yesterday and I didn’t think it was necessary to take a backup of the database.  I was wrong.  The update deleted all columns in the database, so all links to the pictures are gone.  I spent about 5 hours yesterday and today putting back the correct links.  I had to look up all my pages and posts in google cache, figure out which pictures I had used, find them back in about 55 albums and correct the links.  Not fun.  I think I have another 2 or 3 hours work left to get everything back in order.

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  4. VR circuits

    januari 17, 2012 by frank

    Decided to oder a LM1815 and build a new VR circuit like this.

     

     

    Very simple VR circuit.
    Very simple VR circuit.

    Just after ordering I found this circuit.  Needs only a couple of resistors and 2 transistors.  Gonna stick with the LM1815 based circuit though, now that I’ve ordered the chip …

     

     

    Here’s another one with extremely low parts count.  I actually have the Maxim chip, but it’s surface mount so very difficult to solder :(

     

     

    Code for the pic is here.

     

     

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  5. speed conversion

    januari 15, 2012 by frank

    41.5Hz @ 50km/u = ±4800ppm
    41.5Hz @ 50km/u = ±4800ppm

    Put the Westfield with its wheels in the air to test the speedo.  Nothing :( .
    Don’t know exactly why it isn’t working, my oscilloscope gets a reading so it should indicate something.

    At 50 km/h (13.889 m/s) I have 41.5 Hz, iow 41.5 pulses for 13.889 m or 4800 pulses per mile.  This is weird as it’s supposed to be 4000 ppm.  Either way, it should read something, even at 4800 ppm.
    The speedo expects 156000 ppm (32.5 times faster).  I drove the car up to 170 kph, so the speedo should at least indicate 5 kph, but I get nothing.
    Difficult to diagnose if it’s the speedo or a problem with my signal.  Will do some more testing.  Worst case, I make a VR conditioner to directly condition the signal of the transmission to 0-5V and feed that into the speedo.

     

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  6. Oil pressure in Tunerstudio

    januari 7, 2012 by frank


    I have a 90-94 ‘real’ oil pressure sender but no real oil pressure gauge in my S2000 cluster, so I’m using the MS3X to trigger my oil warning light at a preset value.

    The wire coming from the sensor no longer goes to the instrument cluster but to the MS3X on port ADC13 instead.  Since the oil pressure sender outputs no voltage (it’s a simple lineair resistor), a bias resistor is added on the MS3X card in the R67 position.  The oil pressure sender has a fairly low resistance so I used 330ohm to get good accuracy.  Worst case, this pulls about 15mA through the sensor so it shouldn’t be a problem.

    The factory manual mentions these resistor values:
    0psi => 52 ohms
    90psi => 16 ohms

    With a 330 ohm bias resistor we can calculate the corresponding input voltage on ADC13:
    0psi => 5*52/(52+330) = 0.68V
    90psi => 5*16/(16+330) = 0.23V

    With this we can calculate the 0V and 5V values in Tunerstudio:
    0V => (90-0)/(0.23-0.68)*(0-0.68) =  136
    5V => (90-0)/(0.23-0.68)*(5-0.68) = -864

    Enter these values in Generic Sensor Input 1
    sensor – source: Spare ADC (ADC13)
    Transformation: Linear mode

    Now you can use a spare output port to trigger the oil warning light when oil pressure goes below 15psi.  I use these values:
    Output port IAC2
    Power on value: 1
    Trigger value: 0
    Output channel: sensor01 < 15  Hysteresis 2

    If you have a real oil pressure gauge, you probably want keep using it (no point in disconnecting a perfectly good oil pressure gauge!).  You’d obviously need no bias resistor and you need to make sure you do NOT send over 5V into the ADC port.  The gauge works with 12V, so it’s probable that you measure more then 5V over the oil pressure sender (I never checked though).  If so, you’ll have to use a voltage divider to bring it down to 5V.
    Obviously, you’ll have to do some math since you’re now using an unknown bias resistor (easy to calculate its value).

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  7. Megasquirt modifications

    december 31, 2011 by frank

    Honda connectors removed and wires soldered in. I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it's easier to spot mistakes.
    Honda connectors removed and wires soldered in. I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it’s easier to spot mistakes.

    The Honda connectors are removed and new wires soldered in.  I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it’s easier to spot mistakes.  I also made sure to have a stress relief for the wires should I ever accidently rip out the connectors.  It’s not pretty, but it does the job just fine.
    As always, more pictures in the S2000 album.

    The NB miata gearbox has a VR sensor which outputs an 8200 ppm AC waveform.  The miata instrument cluster has a built in VR conditioner to convert that signal to a square wave signal which drives the miata speedo.  This square wave is also used as an input for the megasquirt.  After reading the Megasquirt doc, it appears the megasquirt also has an VSS output so I’m going to (ry and) use it to drive the S2000 speedo.

    MX5 circuit board installed with some stick on spacers to prevent it touching the S2000 pcb.
    MX5 circuit board installed with some stick on spacers to prevent it touching the S2000 pcb.

    The problem is that when I remove the miata cluster, I’ll no longer have the VR conditioner.  Since the megasquirt cannot directly accept the AC waveform, I’d have to build a new VR conditioner in the proto area.  This seemed a bit too much trouble (couldn’t find a LM1815 locally), so instead I removed the small pcb/display (with VR conditioner) from the miata cluster and installed that inside the S2000 cluster.  Just like before, the output of the miata pcb goes to the megasquirt and the megasquirt output will be used to drive the S2000 speedo.

    Modifry ECT module glued to the MS3X module
    Modifry ECT module glued to the MS3X module

    I installed the Modifry ECT module inside the Megasquirt.  This module takes the signal from the coolant temp sensor and converts it to a format that the S2000 cluster understands.  The input of the module taps into the sensor wire, the output goes to the S2000 cluster.  The module is fully programmable and even has an adjustable alarm output (as a warning for overheating for example).

    For my own reference:
    ECU pin 1G is Modifry CLT out to S2000 cluster 2A (V/W) via an additional wire
    ECU pin 2D is MS3 VSS input from MX5 module 2L (W/B)
    ECU pin 2A is MS3 VSS output to S2000 cluster 2O (P/L) via an additional wire

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  8. Progress with the instrument cluster

    december 29, 2011 by frank

    this is what the S2000 cluster will look like in the westfield (miata) housing.
    this is what the S2000 cluster will look like in the westfield (miata) housing.

    The S2000 cluster is a lot smaller than the miata cluster (that was the reason of doing the swap all along), so I’ll have to make a template out of plexi to make it fit.  Shouldn’t be too hard to do though.  A bit of plexi and some paint or vinyl sticky stuff should do it.  I haven’t yet decided which color, probably matte black.

     

    I don’t have the S2000 connectors and I don’t want to cut the wiring of the car, so I decided to remove the S2000 connectors from the pcb and replace them with the connectors from the miata cluster.  Removing the S2000 connectors proved to be a bit challenging and in the process I managed to let my dremel slip and touch the pcb in one or 2 places.  It took me quite a while to repair the damage.  As Murphy would want it, I cut right in the middle of a bunch of very thin traces.  Luckely i managed to avoid cutting into components.

    The problem with the miata connectors is that they are part of the instrument cluster, so I had to cut them out.  It looks worse then it is really.

    S2000 cluster with cutouts for the miata connectors (bottom).I cut these out of the miata cluster.
    S2000 cluster with cutouts for the miata connectors (bottom).I cut these out of the miata cluster.
    Miata connectors glued in and circuit ready to be soldered.It looks messy, but everything is pretty firmly glued in.
    Miata connectors glued in and circuit ready to be soldered.It looks messy, but everything is pretty firmly glued in.

    I cut some holes in the S2000 cluster and glued the miata connectors in.  The left one was a straight fit, the right one needed enlarging and the middle one is an all new hole.  I’ll probably add a couple of screws to make sure they don’t come loose.
    I used the corresponding bits of the circuit board layer and will solder the wires straight on them.

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  9. New instrument cluster

    december 18, 2011 by frank

    Luckely, I can still see the most important part of the tacho, but I'd like to see more of the odo.
    Luckely, I can still see the most important part of the tacho, but I’d like to see more of the odo.

    As I can’t really see all my dials, I decided to buy a Honda S2000 instrument cluster today.  It’s a lot smaller and should be entirely visible through the steering wheel.
    The cluster is a bit of a pain to connect because the S2000 has a 156000 ppm (pulses per mile) speed sensor, while the miata has a 4000 ppm.  I’ll have to come up with a way to multiply the stock signal by 39.

    Also, the coolant sensor does not just measure the resistance (voltage) of the coolant sensor.  Instead, the ecu measures it and sends a 5V signal that has a 30ms high pulse and a 150ms to 1500ms low pulse, relavite to the temperature, so that’ll require some modifications as well.
    Oh, and I’ll have to reprogram the km reading, because I only have 12K kms, not 142K!

    I have no idea yet if it’ll fit inside the Westfield dash as the upper part of the cluster is rather high.  I’ll make it fit if necessary.

    the color filter can be easily replaced with a different color
    the color filter can be easily replaced with a different color

    I’m also planning on changing the color of the display because I don’t like the yellow/orange backlight.  It’s just a piece of plastic, so it shouldn’t be too hard to swap it with a different color.  The bulbs are a bit yellow-ish as well, so I’m going to look into replacing them with bright white leds.

     

    More pics in the S2000 album.

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  10. Megasquirt finished

    oktober 17, 2011 by frank

    All done, need a 2nd cover for the db37 hole.
    All done, need a 2nd cover for the db37 hole.

    Built the megasquirt this weekend.  The MS3 build is a lot easier than my previous MS2 builds.  With the MS3X, most of the extra circuits and flyback diodes can be omitted, greatly facilitating the build.  Again, I made the MS3 fully plug and play.  I really don’t like using extra wiring looms.  The 64pin connector has more than enough room to be put inside the case, so why make a wiring loom!
    Build instructions here.

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  11. Megasquirt is in the house!

    oktober 12, 2011 by frank

    MS3 + MS3X have arrived :)
    MS3 + MS3X have arrived :)

    It took very long this time.  Nearly 3 weeks, but the Megasquirt finally arrived :) .

    Your item was delivered in BELGIUM at 10:22 am on October 12, 2011.
    Arrival at Post Office, October 12, 2011, 7:30 am, BELGIUM
    Customs clearance processing complete, October 11, 2011, 8:44 pm, BELGIUM

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  12. New website

    oktober 3, 2011 by frank


    Decided it was time to move to a new website.  The old site was made with Site@School but development of the software has stopped because of an arguement between the developers.  The main developer decided to release a fork (SyndeoCMS), but he made a new album module and I didn’t like it.  I lost a lot of pictures converting to SyndeoCMS and had to redo quite a bit to get the site going again.
    Site@School is completely dead by now, so there was no point in going on with that CMS.

    I’ve now choosen for WordPress 3.  I had a lot of work transferring my build diary to the WordPress, but at least I now have a mature CMS.  I’m also using a wonderful plugin (Shashin) that allows me to insert my Picasa albums in my website.  All pictures you see on my website are hosted on Picasa, they don’t take up space on my host!  The beauty about it is that all captions I made in Picasa, are visible on my website as well.  With the old CMS, I had to write them in the database, with the result that they’re all gone once I switched to WordPress.

    The one downside to using WordPress is that all my hyperlinks are now dead.  My site had quite some visitors and especially my Megasquirt build how-to.  I guess in time, folks will start finding the link again,  Google will pick it up very fast.

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  13. Some movement

    september 26, 2011 by frank


    But not much

    Customs Clearance, September 26, 2011, 1:59 pm, BELGIUM

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  14. Megasquirt in Belgium

    september 23, 2011 by frank


    Megasquirt is in Belgium already!

    Customs Clearance, September 23, 2011, 7:37 pm, BELGIUM
    Processed Through Sort Facility, September 23, 2011, 7:37 pm, BELGIUM

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  15. New megasquirt

    september 19, 2011 by frank


    Decided to order a new megasquirt today.  Not that I need a new MS, but I just like building them :) .  I’m replacing the MS2Extra with a MS3 + MS3X.  Plan is to try and make a PnP version like my other MS.  Don’t know if the case is large enough though.  If it’s anything like my previous orders, it’ll take less than a week to get to Belgium and 2 weeks to get through customs :( .

    DIYAutoTune.com
    ------------------------------------------------------
    Order Number: 45180
    Detailed Invoice: https://www.diyautotune.com/catalog/account_history_info.php?order_id=45180
    Date Ordered: Monday 19 September, 2011

    Products
    ——————————————————
    1 x MegaSquirt-III w/PCB V3.0 – UnAssembled Kit (MS330-K) = $365.00
    1 x MegaSquirt-III MS3X Expansion Card (MS3Xpander) = $90.00
    ——————————————————
    Sub-Total: $455.00
    United States Postal Service (1 x 2.63lbs) (Express Mail International (3 – 5 business days)): $44.25
    Total: $499.25

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