Help with building your Speeduino, installing it, getting it to run etc.
By Dmitriy
#43685
LAV1000 wrote: Mon Jun 15, 2020 5:04 am Check your cold advance settings in spark.
Observations showed that if I do not connect a VR air conditioner, then Speeduino does not read the data from the crankshaft sensor while scrolling with the starter. I tried to put the resistor R10 1, 2.2-2.6, 10kOm. I found out that the lower the resistor’s feeder the data from the crankshaft sensor are read worse. 10kOm is a lot of resistance. I will select a resistor between 4.7 and 10kom. And without a VR conditioner, I don’t understand how to get the data from the sensor to read at low crankshaft speeds.
Now it works like this: Speeduino creates a primary impulse through the nozzles at the moment the ignition is turned on, this is enough to start the engine, the initial engine speed is enough for speeduino to read data from the crankshaft sensor. Due to VR issues, the speeduino ignition control cannot be transferred.
For now, I see several exits from this:
1 is somehow to teach speeduino to read crankshaft data at low revs.
2 set up VR for normal operation.
3 Replace the crankshaft sensor from inductive to digital.
By LAV1000
#43687
whit this kind of trouble it should be convenient if you had a oscilloscope, can you borrow one ?

And I think we have a misunderstanding.
What do you mean by "VR air conditioner"

VR sensor :
https://en.wikipedia.org/wiki/Variable_ ... nce_sensor
Vr conditioner needs to "tuned" to the sensor hence the resistors R10 for crank and R12 for cam.
You could also try to run it on the crank sensor only but then you need to change the settings to semi sequential.
To concentrate on one sensor at a time.
And then there could be an electrical noise problem which could cause the sync losses at higher rpm.
By Dmitriy
#43700
By "VR conditioner" I mean a chip that converts a sinusoidal signal from an inductive sensor into a rectangular pulse of a digital signal.
I have an oscilloscope but it is not accurate.
By LAV1000
#43703
You mentioned a "VR air conditioner" and I didn't understand that.
So it is just an VR conditioner.

Which type of scope do you have ?
1 or 2 channels ?
And it doesn't have to be precise it just needs to show the waveform from the VR sensor.
By Dmitriy
#43707
LAV1000 wrote: Tue Jun 16, 2020 3:37 pm You mentioned a "VR air conditioner" and I didn't understand that.
So it is just an VR conditioner.

Which type of scope do you have ?
1 or 2 channels ?
And it doesn't have to be precise it just needs to show the waveform from the VR sensor.
This is the signal that the sensor generates. Tomorrow I’ll see what signal is output from the VR chip.
Temporarily soldered a tuning resistor in place of R10, for convenient tuning.
Attachments
IMG_6616.JPG
IMG_6616.JPG (1.66 MiB) Viewed 5447 times
IMG_6607.JPG
IMG_6607.JPG (2.87 MiB) Viewed 5447 times
By LAV1000
#43711
Nice to see what happens.
Check datasheet from MAX9926 chip for max input Voltage.
signal is not symmetrical, but this could be calibration fault on your scope.
What i mean is , if you have 12Vpp signal it should 6Vmax and -6Vmin.
By JHolland
#43712
You need change the voltage range so you can see the amplitude properly, also measure the DC resistance of the vr sensor. You can then perform a reasonable calculation of the current, choose resistors that ensure that the maximum current will always less than the maximum specified for the VR interface at maximum RPM.
By LAV1000
#43718
JHolland wrote: Wed Jun 17, 2020 9:28 am You need change the voltage range so you can see the amplitude properly, also measure the DC resistance of the vr sensor. You can then perform a reasonable calculation of the current, choose resistors that ensure that the maximum current will always less than the maximum specified for the VR interface at maximum RPM.
Can you give an example for the calculation ?

As I always did understand it is the voltage level of the VR sensor which needs to be between certain levels for the MAX9926 to work the right way.
And to get the right levels you need to alter R10 in this case.
And not so much the current, and yes I understand
Volt = Resistance x Current (U = I x R)

If the sensor produces a constant current then it wouldn't be hard to calculate, but I don't think you can assume this.
Don't feel offended, I just think out loud. :D
By JHolland
#43734
The voltage is clamped to the 5V or 0V rail by the VR interface and the datasheet specifies a maximum clamping current. If the maximum current is exceeded then the internal power supply rails become noisy and that causes inaccurate timing. The MAX9924 clamps the input to VCC and 0V so the peak current is (peak input voltage - VCC)/the total resistance. You also need to remember that you can be dumping a significant amount of power into the 5V and 0V rails so you need to ensure good decoupling and layout to avoid generating noise on that rail.
When you perform the calculations you need to allow for the temperature coefficient of the winding which causes a 40% resistance change over 100C, aim to get somwehere close to the maximum current and that will give the highest voltage at low speed.
It helps a lot if you have a well designed trigger wheel, a wheel that just has a tooth chopped out is more approriate for a hall effect sensor.
By Dmitriy
#43753
You guys are really cool, but I'm not as good at electronics as you are.
Maybe the MAX9924 chip is not suitable for high revs.
I have a Yamaha motorcycle control unit, I can take it apart and see what elements are used there.
  • 1
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19

It looks like you have a fuel supply issue. readin[…]

Will this have an updated version about this featu[…]

Vr Conditioner Noise when cranking

I did the fix, but it's not work. I put my setti[…]

Perhaps some different points and pictures. Instr[…]

Still can't find what you're looking for?