For any add-on boards such as VR conditioners, optos and OEM interface boards
By runesm
Lucas@AirLift wrote: Tue Jul 12, 2022 6:55 pm Hey man the controller is in my car and working! But I do have an issue. The fail safe angle on my throttle body, which is also the resting angle, makes my car idle at 2500rpm. If I use a resistor or something to lower the pedal voltage, how can I get the controller to close the plate more without triggering the failsafes?

EDIT: Forgot to mention I modified my 0.43D THT board to output 5v pwm on the idle pin and it works also! So now I just need to figure out how to get the throttle plate to close more and it will be like stock :mrgreen:
It should be able to pull it closed. Did you calibrate the throttlebodys lowest voltage position while it rested, or did you close the flap shut with your finger to get the voltage?
User avatar
By DStage
runesm wrote: Mon Jul 18, 2022 4:49 am It should be able to pull it closed. Did you calibrate the throttlebodys lowest voltage position while it rested, or did you close the flap shut with your finger to get the voltage?
I think in this case we are talking about the hall effect or whatever based TPS so the voltages are constant.
Lucas@AirLift wrote: Tue Jul 12, 2022 6:55 pm Hey man the controller is in my car and working! But I do have an issue. The fail safe angle on my throttle body, which is also the resting angle, makes my car idle at 2500rpm. If I use a resistor or something to lower the pedal voltage, how can I get the controller to close the plate more without triggering the failsafes?
SO I guess you are using the VTA1 which according to the spec can be between 0,69 and 0,93V. The default fail safe voltage on the controller is around 0.8V so you may indeed have a problem. Although I do not exactly follow how you made it work at all and with such high idle ;-)
Anyway, you can modify values of R14/15/16 to get different fail safe voltages. For example changing R15 from 43k to 75k (just chosen one of the values already existing in the circuit) would set the lower fail safe at about 0,5V and the upper one at 4,5V. Assuming your harness is good and you have no ground issues this should be still safe.
You can manipulate those values in a way to only lower this one threshold of course but we'd have to calculate and change at least 2 out of those 3 resistors.

Can I just ask if it works without the idle PWM? or it closes completely via fail safe in such case?
The idle input is actually held at at least 0.9V normally so your high idle may be caused by this as well (or only by this, as I said your explanation about the fail safe did not compute in my brain ;-) ).
We may have to modify something around R24/26/27 but that's easiest to determine via simple simulation so I can do it for example tomorrow as it's close to 3 AM here at the moment :P For starters R27 could be changed to something like 1,5k, not sure what would be the 100% PWM voltage but the 0% should be around 0,65V. Alternatively if you would like to use one of the values already in the circuit you could add 3,3k or 5,1k in series with R24 (0,71V and 0,64V respectively) or put two 3,3k in parallel in place of R27 (~0,71V) or even try just adding 3,3k in parallel to R27 2,2k (~0,58V, don't worry it can't trigger the fail safe).

If my late night thinking is worth anything I suspect you'll need both mods so the previous chapter about R15 still applies.
Hey so I haven't given an update in some time.. I do have this working fairly well. I ended up using the 1.5-3.8v output from the throttle body, and then am using the boost control output from the Arduino as the pedal input. This works awesome as I have a nice map that I can use to adjust the output to make it non-linear for better part throttle resolution. I am bypassing the FET and using the 5v output direct from the Arduino pin.

I did perform the resistor mods as you outlined, swapping r15 for a 75k and r27 for a 1.5k. That said, I still cannot get the controller to target a voltage below .8v. Before the mods it would target a low of 1.06v. The sensor in my stock throttle body I would like to use has a range of 0.73v to 4.48v. I have a second throttle body from a Mazda 2 that has a range of 0.49v to 4.5v that I would like to use as it's brand new, but I just cant seem to get this thing to target a voltage that low. Any ideas? I have a book of any resistor value you can think of so if you have an idea of different values to use I can try them out.
User avatar
By DStage
I'll think about it and let you know as it's again late ;)

Can you remind me if you are actually using the accelerator input at all or just the idle input? I suspect there may be something going on with the diodes at the input and I'm thinking how to delete them for your application. Could you measure the voltage on both sides of D8when there is no input signal at idle pin (or it's simply 0% PWM/grounded)? This might not be the diode but this measurement will help me anyway.
User avatar
By DStage
Hi again.

I gave it some thought. My advice would be to change R27 to 1k and R15 to 100k. This should fit this second throttle of yours even considering the voltage drop on diodes. I must note that the upper limit comes close to supply voltage so there's not a big margin for fail safe so you have to take care of good quality harness and grounding.
User avatar
By DStage
Hello everyone. Some time ago I mentioned that I was working on newer variant of my controller. I had some spare hours recently and came up with v1.4. Originally I was thinking about v2.0 with semi-auto tune and optionally digital mapping but I see some difficulties in JLCPCB library when it comes to digital potentiometers (the core would still stay analogue as it is proven to work and I still think it's safer than a digital one). The idea was to make it work even without the MCU (probably Arduino nano) so I need non volatile memory in pots and that's not common in those in JLC stock. Anyway, another reason to go with this intermediate v1.4 was to keep changes in bay and test the new concepts first.

Here's the beta of schematic and PCB for v1.4, I need to order those and run some tests. Although it wasn't a strict condition I managed to squeeze everything in the same PCB dimensions. It is really maxed out in the control part now ;-) About 80% of the layout is exactly the same as it was in v1.3.

The change in the remaining 20% goes to a different calibration method and input circuits. The previous versions were based mainly on assumption that it is used with pot based TPS and gas pedal and the calibration was pretty much about changing the resistance on top and bottom of those pots to change their voltage range. However, this proved to be limited and somewhat difficult when one wanted gas pedal or throttle based on different technology and in general having voltage output instead of a resistive one.

Now in v1.4 there's an additional amplifier on both inputs that provide means of changing amplification (k-factor) and offset of the input signal. In other words, it is now possible to multiply (or divide looking from a different perspective) the input signal by a k factor in a range of approximately 0.5-2. The goal is to either sterach or narrow down the voltage difference between open and closed throttle / pressed and unpressed gas pedal to 3V.

For example, if we start with 0.7V at closed throttle and 3.5V at fully open (and we know it either from documentation or from simple measurement) the difference is 3.5-0.7=2.8V, therefore we need to amplify the signal a bit. k=3V/2.8V=1.07 which will give us 0.7V*1.07=0.75V and 3.5V*1.07=3.75V and the difference is now exactly 3V.

Now we need to move both of those values so they are fixed at 1V and 4V (as you remember by default the fail safe thresholds in previous versions were set to 0.8V and 4.2V so the goal is to be centered between those). That's where the second set of pots comes into play, they set the offset. The "neutral" position of offset pot is 2.5V, in our case we need to move both values by 0.25V. This can be set via calculating the required voltage at regulating pot or by measuring the result at opamp output with closed throttle when turning the pot.

There are now 2 pairs of test points on the PCB equipped with a small hole so it's easier to localize and keep the multimeter probe in place when calibrating. The calibration procedure I have in mind has the steps actually backwards to those described above - I will add a simple spreadsheet (and equations for those that wish to do it on their own) where you put in the voltage levels of your TPS / gas pedal and it will give you the required offset voltage to be set which then you measure on one test point per input. The k factor is then provided just for your information as all you need to know is which direction you need to turn the amplification pot and measure the result on opamp output, that is the second set of test points.

It may sound somewhat complicated at first but it should be actually easier and faster then the current calibration method. Plus there are no limitations to the type of position sensors as long as their signals are between 0 and 5V. There are now two new cable connection points on the PCB to provide GND and 5V power to both gas pedal and TPS.

For those of you that like to dig deeper in the schematic - yes, the input signals will be reversed meaning the level on next stage input (the filter known from previous versions) will be 4V at closed and 1V at fully open throttle. Since the gas pedal behaves the same way only thing we need to do is reverse the polarity at the motor connectors (I think hehe). For the same reason the IAC input had to be rearranged and also reverse the input PWM. I also know that the placement of the filter as the second stage instead of the first is not ideal but I had to make a compromise to have the IAC working properly and not requiring additional filtering and/or calibration.

I'm not yet putting it on github as I believe this new concept has to be verified first. If you would like to have a try though I can provide all necessary files to early adopters.
ETC v1.4 schematic.png
ETC v1.4 schematic.png (113.21 KiB) Viewed 5560 times
ETC v1.4 render top.png
ETC v1.4 render top.png (480.75 KiB) Viewed 5560 times
User avatar
By DStage
v1.4 prototypes have arived. I think there will be one rework needed so after testing I will put v1.5 with corrections to the Github. But first need to find time and strength for testing ;-)
IMG_20230310_172205.jpg (3.78 MiB) Viewed 4847 times
User avatar
By DStage
I'm waiting for few components to finish mods and test on v1.4/v1.5.

In the meantime I have updated repo for v1.3. There are few changes in th BOM. One is for the TPS input filter - new frequency should fix the problem of throttle flapping and the need of C2 and C3 removal. The second one lowers the motor PWM frequency from ridiculous 300kHz to more reasonable 100kHz which should make transistors run much cooler. There shouldn't be any side effects. ... /main/v1.3
  • 1
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12

If you look at cars that have superchargers with c[…]


I'm probably missing a fundamental understanding h[…]

On a pitbike engine I was able to use the pickup c[…]

AE below 1000RPM

The problem mainly is that the MAP value update[…]

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