Search found 92 matches

by Sudo
Wed Sep 10, 2014 4:01 pm
Forum: Hardware
Topic: Possible option for generating VR sensor signals
Replies: 22
Views: 5453

Re: Possible option for generating VR sensor signals

Technically that's a symmetrical wheel that have different zones. Not any different from missing tooth. That's not the non-symmetry I was referring to, like the 1 tooth wheel you showed in the previous thread where it will product no symetrical signal. This wheel one will actually produce a symmetri...
by Sudo
Wed Sep 10, 2014 1:44 pm
Forum: Hardware
Topic: Possible option for generating VR sensor signals
Replies: 22
Views: 5453

Re: Possible option for generating VR sensor signals

In reality you will not find a non symmetrical high count wheel. You only see that with 1-4 ish, in that range. They are not only harder to manufacture, they provide no real advantage at higher speed. Its just not practical especially for automotive application. I'd be damned if you can find a non s...
by Sudo
Wed Sep 10, 2014 12:18 pm
Forum: Hardware
Topic: TMS570 MPU board
Replies: 15
Views: 3730

Re: TMS570 MPU board

Proper routing can easily be solved with more layers as well. Then it's more of a cost issue then a routing challenge.
by Sudo
Mon Aug 25, 2014 9:37 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Am I missing something somewhere regarding what duty cycle means? To me, a 25% duty cycle means during one period, 1/4 spent high, 3/4 spent low... 25% at 'high' voltage and 75% at the low voltage. Thresholds obviously play a part in this as well, though. 75% and 25% duty is interchangeable in my b...
by Sudo
Mon Aug 25, 2014 8:39 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Yes, and by providing a 25% duty cycle signal instead 50%. The DC is not zero anymore because of the imbalance signal. The average is above zero in Russian's case. His signal looks like 75% high and 25% low, which result as a ~3V DC if the signal is +/-6V peak to peak. That's my point. Russian, just...
by Sudo
Mon Aug 25, 2014 8:09 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Both of the center of Valley and Teeth are zero crossing........... It depends on which one you choose. The one with more width is the less reliable one. And that typically is the valley. So let's just let this lay in state. :D Exactly, so why are we purposely inducing a 25% signal? When in reality...
by Sudo
Mon Aug 25, 2014 8:00 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Nothing about the valley is mentioned there, and that's what I've been saying- what happens in the valley, the void between teeth, doesn't matter... usually. The valley HAS a zero crossing point. THAT's what I am saying. It is near 50%. Just because we can't detect it electrically, doesn't mean it ...
by Sudo
Mon Aug 25, 2014 7:49 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Nothing about the valley is mentioned there, and that's what I've been saying- what happens in the valley, the void between teeth, doesn't matter... usually. The valley HAS a zero crossing point. THAT's what I am saying. It is near 50%. Just because we can't detect it electrically, doesn't mean it ...
by Sudo
Mon Aug 25, 2014 7:27 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

I am going to beat this to death... Still need more convincing?
by Sudo
Mon Aug 25, 2014 7:12 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Did you notice that in the last picture, the VR sensor is obviously reversed? That's Irrelevant. Point is: Zero crossing happens in the center of the teeth where it switches from maximum positive flux to maximum negative flux. And vise versa for the valley where it switch from negative minimum flux...
by Sudo
Mon Aug 25, 2014 6:47 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

You have, in a round about way, proven exactly what I was saying. With a toothed wheel, you're looking for the positive-going-negative transition, with a notched wheel, you're looking for the negative-going-positive transition. In either case, it's the sharp edge where the voltage swings quickly fr...
by Sudo
Mon Aug 25, 2014 6:33 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Here's a trigger with just under 1mm wide teeth and valleys. DSC00002.JPG Are you sure the distance between adjacent teeth is equal to the valley? My micrometer says it's almost 3mm between teeth. This wheel will product zero crossing at the center of each teeth (maximum flux) and center of each va...
by Sudo
Mon Aug 25, 2014 6:11 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

The 'valley' between teeth is nothing more than empty space, and is typically where a VR sensor's output should be 0 volts. Nothing about the valley should be considered other than the period the wheel spends in the valley, and even then that is just a waiting period for the next tooth to come into...
by Sudo
Mon Aug 25, 2014 5:43 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

http://rusefi.com/forum/download/file.php?id=741 . That is NOT the wheel being used for the 24 teeth. I had the 97 accord myself. The teeth look more like what I showed you. Again, for the sole purpose of my critizism. I am talking about the 24 teeth!! Not the 1 teeth or the 4 teeth, because those ...
by Sudo
Mon Aug 25, 2014 5:39 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

The wheel I showed you is symmetrical. It is symmetrical from the CENTER of the teeth to the CENTER of the valley, then to the next center of the teeth. It is a mirror image. The valley doesn't have to shape like the teeth to be symmetrical. Study it a little bit... And tell me that's not symmetrica...
by Sudo
Mon Aug 25, 2014 2:28 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

VR sensors do not always generate purely symmetrical outputs, to think otherwise is wrong. VR sensors do not always generate pure sine wave outputs, to think otherwise is wrong. Peak V+ is around 18, valley V- is about -2. Amazing, isn't it? The peak is WAY more than the valley. And that is from du...
by Sudo
Mon Aug 25, 2014 12:16 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Also it's much worse at low RPP Let me make it clearer. Zero crossing point does NOT vary with RPM. Again, it is worst at low only because the input threshold is not perfect zero. At low RPM, it reaches near zero very early. But that doesn't mean it actually crosses zero. So what it ''looks'' like ...
by Sudo
Mon Aug 25, 2014 3:00 am
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Ideal VR is symmetrical believe it or not. I fully understand physical tolerance and real world affects. But the concept is and will always be symmetrical. The point I was making is that Russian was using RS232 to mimick what the Honda ECU would see coming out of its own TTL output. That idea is fla...
by Sudo
Fri Aug 22, 2014 5:25 am
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

I don't understand why you say not using 50% is matching OEM? Real VR signal is always 50% duty cycle, regardless of how the input driver interrupts it. The transient may not look like 50%, but in terms of zero crossing, it is always 50%. The problem with not using 50% with RS232 is that you will ha...
by Sudo
Fri Aug 22, 2014 1:43 am
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Another thing to note is that you are not giving it 50% duty cycle? I think it would be better to be 50% duty cycle. I understand that is how the wheel profile looks physically. But electrically, it doesn't behave that way. During the missing teeth transistion, it essentially floats to 'zero' at aro...
by Sudo
Thu Aug 21, 2014 4:45 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

Oh, nice. So based on the schematic, my theory doesn't apply. VR- is ground. I think you might want to try 1uF for the charge pump caps and go from there.
by Sudo
Thu Aug 21, 2014 2:20 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

The biggest unknown question is that we really don't know how Honda designed their VR inputs. If VR- is expected to float due to an differential input with limited common mode range, and we clamp VR- to ground, is it possible that you end up clipping the VR+ signal to some sort of body diode or prot...
by Sudo
Sat Aug 16, 2014 2:10 pm
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

I don't have much time, I am not sure when I can do it. :( But I can offer some suggestions. Before finalising it to use RS232 for VR simulation, have you tried the differential driver idea that I talked about previously? You don't need any hardware to simulate this. Using your VR+ output from your ...
by Sudo
Tue Aug 12, 2014 3:06 am
Forum: Hardware
Topic: stimulator board
Replies: 182
Views: 37553

Re: stimulator board

That's looks like a defect to me. I don't see that on my or your gerbers. That round capacitor silkscreen is definitely wrong and not even part of the board. Magically appear! :shock:

Do you actually see the GND copper touching EIN_1?
by Sudo
Mon Aug 11, 2014 2:16 pm
Forum: Hardware
Topic: 3D printing ECU case - cost?
Replies: 55
Views: 8108

Re: 3D printing ECU case - cost?

There are games you can play to filter EMI with a 3D printed plastic case design. One thought is to design a multi layer case that allows the user to sandwich aluminum foil in the walls of the case. Cost would be cheap to print. But I think the better point for this idea is that it will be totally D...
by Sudo
Sun Aug 10, 2014 1:20 am
Forum: Hardware
Topic: Frankenso - ECU shield compatible with OEM case / official
Replies: 510
Views: 110911

Re: Frankenso - ECU shield compatible with OEM case

Diode to the USB power is a good idea. I've use ideal diode IC to reduce the voltage drop to 'OR' USB power with other sources. But you may not need it if you don't care about the diode drop.

http://www.linear.com/product/LTC4411
by Sudo
Tue Aug 05, 2014 7:32 pm
Forum: Hardware
Topic: Frankenso - ECU shield compatible with OEM case / official
Replies: 510
Views: 110911

Re: Frankenso - ECU shield compatible with OEM case

Yes, it has to do with inrush current. The general rule is that maximum load perceived by the USB power rail prior to enumeration of a 500mA device needs to be below 10uF || 44 ohms. But once enumerated to a 500mA device, you can switch on the addition load. I usually solve this problem by using a F...
by Sudo
Tue Aug 05, 2014 1:06 pm
Forum: Hardware
Topic: Frankenso - ECU shield compatible with OEM case / official
Replies: 510
Views: 110911

Re: Frankenso - ECU shield compatible with OEM case

Not sure if you've taken into account of the initial 10uF limitation on USB power. I will take a look at the schematic later tonight.
by Sudo
Sun Jul 20, 2014 5:51 pm
Forum: Hardware
Topic: Cheap Potting with Tegaderm?
Replies: 1
Views: 932

Cheap Potting with Tegaderm?

Just browsing cheap way to pot or encapsulate small modules and ran into this link:

http://www.arie.co.za/potting-electroni ... -silicone/

Using Tegaderm will allow silicon to breath to cure. It seems like a great idea.
by Sudo
Mon Jul 07, 2014 10:14 pm
Forum: Hardware
Topic: Frankenso - ECU shield compatible with OEM case / official
Replies: 510
Views: 110911

Re: Frankenso - ECU shield compatible with OEM case

I normally use Saturn PCB Design tool. http://www.saturnpcb.com/pcb_toolkit.htm What you are looking for is Zdiff. The Kicad tool doesn't show the result for that. Why is your "H" value so high? Assuming we will use OSH, It should be 6.7 mils according to their stackup. http://support.oshpark.com/su...