Search found 92 matches
- Wed Sep 10, 2014 4:01 pm
- Forum: Dev: Hardware
- Topic: Possible option for generating VR sensor signals
- Replies: 24
- Views: 23102
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...
- Wed Sep 10, 2014 1:44 pm
- Forum: Dev: Hardware
- Topic: Possible option for generating VR sensor signals
- Replies: 24
- Views: 23102
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...
- Wed Sep 10, 2014 12:18 pm
- Forum: Dev: Hardware
- Topic: TMS570 MPU board
- Replies: 15
- Views: 13146
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.
- Mon Aug 25, 2014 9:37 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 8:39 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 8:09 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 8:00 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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 ...
- Mon Aug 25, 2014 7:49 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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 ...
- Mon Aug 25, 2014 7:27 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
Re: stimulator board
I am going to beat this to death... Still need more convincing?
- Mon Aug 25, 2014 7:12 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 6:47 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 6:33 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 6:11 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 5:43 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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 ...
- Mon Aug 25, 2014 5:39 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 2:28 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Mon Aug 25, 2014 12:16 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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 ...
- Mon Aug 25, 2014 3:00 am
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Fri Aug 22, 2014 5:25 am
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Fri Aug 22, 2014 1:43 am
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Thu Aug 21, 2014 4:45 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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.
- Thu Aug 21, 2014 2:20 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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...
- Sat Aug 16, 2014 2:10 pm
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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 ...
- Tue Aug 12, 2014 3:06 am
- Forum: Dev: Hardware
- Topic: stimulator board
- Replies: 182
- Views: 148386
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!
Do you actually see the GND copper touching EIN_1?
![Shocked :shock:](./images/smilies/icon_eek.gif)
Do you actually see the GND copper touching EIN_1?
- Mon Aug 11, 2014 2:16 pm
- Forum: Dev: Hardware
- Topic: 3D printing ECU case - cost?
- Replies: 72
- Views: 80121
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...
- Sun Aug 10, 2014 1:20 am
- Forum: Dev: Hardware
- Topic: Frankenso - ECU shield compatible with OEM case / official
- Replies: 552
- Views: 582515
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
http://www.linear.com/product/LTC4411
- Tue Aug 05, 2014 7:32 pm
- Forum: Dev: Hardware
- Topic: Frankenso - ECU shield compatible with OEM case / official
- Replies: 552
- Views: 582515
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...
- Tue Aug 05, 2014 1:06 pm
- Forum: Dev: Hardware
- Topic: Frankenso - ECU shield compatible with OEM case / official
- Replies: 552
- Views: 582515
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.
- Sun Jul 20, 2014 5:51 pm
- Forum: Dev: Hardware
- Topic: Cheap Potting with Tegaderm?
- Replies: 1
- Views: 3100
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-electronics-with-silicone/
Using Tegaderm will allow silicon to breath to cure. It seems like a great idea.
http://www.arie.co.za/potting-electronics-with-silicone/
Using Tegaderm will allow silicon to breath to cure. It seems like a great idea.
- Mon Jul 07, 2014 10:14 pm
- Forum: Dev: Hardware
- Topic: Frankenso - ECU shield compatible with OEM case / official
- Replies: 552
- Views: 582515
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.oshp...