Hi,
So I built my second vr circuit based on this diagram. http://www.msextra.com/ms2extra/MS2-...nition.htm#2vr

This was before I found H4inf's PDF

I was wondering if there is any reason this circuit won't properly condition the second VR signal, If so i'll gladly build the other circuit. Just thought I would ask before going through the trouble. Thanks in advance

Sean

 

the 1-shot output from the circuit that you built might not be wide enough for the chip to catch it if you're using ms2/extra 1.0.2

With ms2/extra 2.0.0, it should be OK, but you might end up with noise problems. For 2.0.0 you should put the chip into zero-crossing mode, and not use the 1-shot output.

Ken

 

im sorry but what do you mean the one shot output. im trying to do mine as well with the jimstim and it wont work. i used h4in pdf document "how to" is there anything different i should do from h4in write up?

 

Hrmm, I'll have to read the lm1815 datasheet so I can explain the "one-shot" better.

Basically the lm1815 has several modes. One of them creates a square-wave with a width that doesn't change, and the rising edge of the square-wave is where zero-crossing happens on the VR signal (when the tooth passes the sensor).

The other mode is "zero-crossing" mode, which generates an edge each time the VR signal goes through 0 volts. Many have found that this works better for them with their setups (not just on rx7's).

Ken

 

can you please give me some more input on that. im not as electronically inclined as you are ken and believe me i appreciate the knowledge.
also i cannot load the 1.0.2 firmware. i have the 2.0 loaded but it will not let me go back to the 1.0.2 firmware . i dont know if the 2.0 is giving me the problems but the boost control feature is nice to have

 

Here you can find the data sheet for the lm1815, http://www.national.com/ds/LM/LM1815.pdf, If you aren't electronically inclined learn to be!

 

thanks for link i appreciate it definitely trying to learn as much as i can

 

If you can get access to an oscilloscope it is very easy to understand how the thing works because you can see the traces change as you enable different modes.

Mine is not working either, but I will enable that mode today maybe and see if it works.

 

The LM1815 can't be triggered by the jimstim as the output signal of the jimstim never crosses zero. You will need to place a .01uf capacitor in series with the second trigger on the jimstim to properly trigger the LM1815.

The easiest way is to screw one leg of the capacitor into the corresponding pin on the jimstim and use one of the jumper plugs to connect the second trigger output and the other end to the other leg of the capacitor:



Just to give you an idea, here's a graph of the difference. The top graph is the jimstim output, the bottom is the jimstim output coupled with a .01uf cap.

 

thanks gross polluter that makes things a lot easier with the pictures and your write up. im starting to grasp how this works now.