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Nifty Wideband to Check Out [JAW, old thread] 
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EDIT: Add link to the best wideband thread on the internet: viewtopic.php?f=6&t=2267

Oh, yeah, sorry, we're talking different things - to your eyes, sure. I have my doubts anything but the first, maybe second digit (ones, maybe tenths I mean) matters to your eyes!

I meant to the ecu, for tuning/EGO/logging!

Now. More Important stuff:

Quote:
1) on the 5v supply, the current draw should be a max of 200ma,
including the display, without the display it would be a max of
100ma. On the 12v supply it would be a max of about 2A, that is
for the sensor heater.
2) When I did the gauge I was just after ease of assembly and not
after space savings. I am going to redo the gauge in a month or so
so that the LED sits ontop/behind of the display IC.
3) The interface is digital, it is an SPI interface.

There is no official test of my wideband vs LC1 or others, but
based on my testing and development work the AFRs are typically
within 0.2 of them. Other users have experienced that JAW and
LC1 are outputting almost identical AFRs. I have yet to really
hear of anyone complaining about large discrepancies between JAW
and another wideband reader.

Regards,

Alan To


And after another pointless reply of mine he adds:

Quote:
Hi,

The thing is that, if you look at the hardware everyone is using similar hardware and it all revolves around the microcontroller. I use an Atmega88, innovate uses the Atmega168, and Tech edge uses the Atmega168. I am sure others use a very similar micro, if not Atmega it will be zilog or PIC. The part that is really critical is the code for the micro, and often you can not really measure how good the code is based on price. I pretty much read and follow the datasheet for the bosch sensor,and design my system according the datasheet specs, if there is some secret that is not in the datasheet then I am at a disadvantage to the competition that knows.

The most advanced part of a wideband system is the sensor, Bosch did a good job with the sensor, so they pretty much should get most of the credit. I get a little kick from selling a DIY controller kit that is cheaper than the sensor itself.

I am very interested in EMS's, a long term project of mine is to build my own ECU.

I live in toronto Canada.

I do not mind you posting my email.


So I'll send him a link here and hopefully he brings some more talent and enthusiasm to our group.


Last edited by Fred on Thu Aug 25, 2016 1:10 am, edited 1 time in total.

Add link!



Mon Jun 09, 2008 10:37 pm
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Thanks for the information Abe! Most appreciated.
8InchesFlacid wrote:
So I'll send him a link here and hopefully he brings some more talent and enthusiasm to our group.
A big thanks for that too!

Fred.

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Tue Jun 10, 2008 6:42 am
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Hi All,

My name is Alan To, I am the designer of JAW. I am here to answer any questions you may have. Thanks 8inches for inviting me and thanks Fred for giving me permission to post.

I don't have any hangups about JAW and I will be open to discussing its flaws and shortcommings as well as it merits. Please keep in mind that low price was one of the primary objectives of JAW.

Regards,

Alan To

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Tue Jun 10, 2008 3:24 pm
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toalan wrote:
thanks Fred for giving me permission to post.

For the benefit of others reading this in the future, as I said in PM there really is no need to ask :-)

Quote:
I don't have any hangups about JAW and I will be open to discussing its flaws and shortcommings as well as it merits. Please keep in mind that low price was one of the primary objectives of JAW.

Perhaps you could start the conversation by giving everyone a run down on its strengths and weaknesses? It's obvious that you are an open honest kind of guy, and I REALLY appreciate that and would love to hear what you have to say about it.

Fred.

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FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Jun 10, 2008 3:35 pm
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Weaknesses:
  • RPM pickup is for 5 volt square wave, for interfacing with a tach you will need to put in atleast a resistor in series with the tach signal. Ideally you want to have a resistor+cap+diode circuit. This issue is addressed with the new JAW I will release in July
  • Slow response time, the response time is ok considering the sensor is pretty slow itself. But speaking as an engineer there is alot of room for improvement. This will be fixed with a firmware update soon.
  • Poor input voltage protection, I just have a zener for over voltage protection. The new JAW unit will have fully voltage protection; over voltage, reverse polarity, resettable fuse.
  • DIY kit that is closed source makes it hard to troubleshoot. Schematics for the new JAW unit will be available to help with debugging and troubleshooting.
  • Uses a voltage regulator to supply the sensor heater with power, this requires a heatsink and makes the unit larger and ugly. The best way to supply the sensor heater with power is to use a mosfet to PWM switch the heater on/off, but this creates noise that goes everywhere, I could put filters everywhere to deal with that, use external Delta sigma ADCs, or use a switching power supply for heater power. The voltage regulator + heatsink is less than $1, any other way would cost alot more.
  • Minimal documentation, I do not like writing documentation, I set everything up so that things are obvious to the technically inclined.
  • Datalogging software is poor, No fancy graphs just numbers. I am not a competent object oriented programmer so that was the best I can do. The source code for the windows software is available.
  • only 2 external 0-5v datalogging channels, others have more but some have none.

Strengths:
  • Price, you can get a DIY kit with display for less than what others charge just for a gauge.
  • Digital communications between the display and unit, more accurate, faster updating and you can set the refresh rate.
  • Resolution of 0.01 lambda, this is based on the ADCs that I use and the fact that the bosch sensor itself is only offers 0.01 lambda resolution.
  • Has datalogging, most budget widebands do not have that.
  • 2 output channels, most widebands have this too.
  • Using a voltage regulator for the sensor heater power supply puts very little stress on the heater. Some units that use PWM for heater power are more harsh and have a tendency to kill the heater.

That is all I can think of for now. The new JAW unit and firmware update should address most the shortcomings, I am also working on new windows software and better documentation.

Regards,

Alan To

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Last edited by Fred on Tue Jun 10, 2008 7:56 pm, edited 1 time in total.

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Tue Jun 10, 2008 6:14 pm
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For the heater circuit- can a CRT heater chip be used? Like this one -
http://www.datasheetcatalog.org/datashe ... 025BEB.pdf

Also i just downloaded the C# code from your website - i am parsing through the code now to see if a graphing screen could be added. Just from cursory glance - it seems the datalog button starts timer1 and timer1 tick gets the data from port and puts it into DL_Data structure - so if i wanted to add graphs i would reference DL_Data - am i right in those assumptions?


Tue Jun 10, 2008 7:22 pm
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shameem wrote:
For the heater circuit- can a CRT heater chip be used? Like this one -
http://www.datasheetcatalog.org/datashe ... 025BEB.pdf


Looks nice! I wonder how noisey it is, probably pretty good? The downside is that it only supplies 1 amp. A couple in parallel might work, I suppose, but I don't know how they interact.

Also, couldn't panasonic have hired someone who spoke English to write that spec? :-P It reads like some hobbyist from norway wrote it. Who cares, if it works.


Tue Jun 10, 2008 8:54 pm
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