[Wbo2] Using the Bosch WB sensor with L1H1 circuit board

[Peter Gargano]

allen brown wrote:
> Maybe ask them about the display fiasco and the use of
> commercial grade parts. . . 

You're referring to the so-called "Cold Fix" for the 5301 display. 
That 5301 display works with the DIY-WB.  Note: we don't sell it 
anymore, but the design is still available free on-line here :

   http://techedge.com.au/vehicle/wbo2/5301.htm

for the free firmware, see "Obtaining the Software" paragraph :

   http://techedge.com.au/vehicle/wbo2/5300.htm

I get one or two request per week for the free firmware (hex file 
only, not in source format, but the original Silicon Chip source I 
modified is available).

The 5300/5301 design used a PIC processor rather than the faster, and 
nicer Atmel processors we now use. On the first units we sent out we 
had mis-programmed the "fuses" so that it worked fine until it got 
very cold, and the internal pull-ups changed in value so much that the 
unit didn't work as was intended. Using the correct "fuse" setting 
that the circuit was designed for solved the "problem".

It would have made no difference if we had used a commercial or 
industrial part, we just didn't find there was a problem until the 
Norther winter arrived. I could only reproduce the problem here with a 
"can of cold".  We never made a secret of the problem ....

   http://techedge.com.au/vehicle/wbo2/1v5/fixes.htm


Allen, you also asked, by implication, what we currently use ...

The processor in the 2A0 DIY kit is an Atmel Mega8 running at 16 Mhz 
with an industrial temperature range. Here's a cut and paste from the 
data sheet (the P in PI indicated a Plastic DIP package, I = Industrial).

   ATmega8-16PI    Industrial     (-40?C to 85?C)

You can see an image of the 2A0 constructed PCB with "PI" processor 
here  - this image has been up on the web site since September 2004 ...

   http://wbo2.com/2a0/const/r4comp.jpg

You can also see we have three quad op-amps LMC6484-IN - again 
industrial temp range, but the 74HC4052 muxes are not industrial range.


Peter Gargano
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