V3.3.0 firmware / configuration software - for V3 hardware

[brentp]

Patriq,

What type of sensor are you using? if it's a standard thermistor type sensor, then use the schematic you posted, retaining the pull-up resistor. Then wire up the sensor in this manner:
http://www.autosportlabs.net/MJLJ_V4_ve ... e_resistor

For the hard rev limiter- yes: it is designed to fit in the slots of the V3 and V4 controller.

[DannyP]

I still haven't calibrated my sensor. Autometer was very helpful, though. They emailed me a pdf of their sensor specs: temp vs. resistance. Should be fairly easy to chart the output voltage of the circuit, just have to get to it.

[Patriq]

Patriq,

What type of sensor are you using? if it's a standard thermistor type sensor, then use the schematic you posted, retaining the pull-up resistor. Then wire up the sensor in this manner:
http://www.autosportlabs.net/MJLJ_V4_ve ... e_resistor

For the hard rev limiter- yes: it is designed to fit in the slots of the V3 and V4 controller.

Yes, it is a standard type - one wire only. Grounded through the engine. I bought an extra instead of using the one currently in use for the dial on the dash.

Could I use whatever type of capacitator for the signal circuit prior to the processor, as I asked about in the previous post ?

What I was wondering about regarding the hard rev limiter, was if I could use the spare holes in that board instead of bying a experimental board that would come in addition to the hard rev limiter board and the original board?

Thanks again Brent. I was especially pleased to see all new products since I last visited this website a couple of months ago ! Keep up the good work !

[brentp]

Hi Patriq,

Thank you for the kind words!

For the capacitors- use standard ceramic, 50V. The Hard Rev limiter board does not have extra holes for prototyping. If you're referring to what I think you are, those holes are for passing thermal energy from one side of the board to the other. However, not all space is consumed by the hard rev limiter; you'll be able to fit a secondary board side by side in the same case.

Regards,

[Patriq]

Ok, thanks Brent !

Oh - those are vent holes !
Ok, I'll add an expermintal board to the list of components I'm ordering.

Regards,
/Patriq

[Patriq]

Here is the result file from my easy-therm.

Load it in mjlj configurator. At known temperature check what aux gauge reads. If necessary edit the file and add more zeros from the top or from the end of the file, but keep it at 256 lines.

Not sure if it will be correct, post back the results.

Yvan - did you measure from the sensor with everything installed in the car when you tried it in a glass of water?
Since I guess the result will be depending on the system you are running on ?

Since U=I*R, R will be the same in any system since it's the same sensor. But U will differ with the battery you are using.

Also - I don't quite get it. Is MJLJ reading the U value ? Is I constant and since the resistance differ with the water temperature, so does also the voltage U ?
So I is determined by the capacity of the battery you are using in your auto - and U is then determined by the R of the sensor ? Which also means that you would have to test the system in the car you are using since any resistance added by the circuit will affect the value.
Also it would need to be recalibrated if you change battery - since then the Ampere from the battery could change ?

Or am I completely wrong here?

[DannyP]

Patriq, the MJLJ is reading a voltage output, not current. Since you have a 5V source, buffered through some caps and resistors, then through the variable resistance to ground, thus changing the output voltage. Your 5v is regulated and doesn't change, so the output should be very stable no matter what your 12v battery is doing.

[Yvan]

Patriq, the mjlj only reads resistance from the temp sensor, and I did not bother with deep analysis how it operates. I believe that Brent did a good job with mjlj design, and, as DannyP wrote, mjlj has regulated voltage (12V and 5V), so you do not have to worry about it.

BTW, can you test if user configurable outputs switch on and off with the temp changes. I still have the same problem (and hot weather is here, I could use this feature to switch auxiliary a/c fan on and off).

[Patriq]

Patriq, the MJLJ is reading a voltage output, not current. Since you have a 5V source, buffered through some caps and resistors, then through the variable resistance to ground, thus changing the output voltage. Your 5v is regulated and doesn't change, so the output should be very stable no matter what your 12v battery is doing.

Ok, that's more what I would have thought.

So, if I would just run the MJLJ in the kitchen I should be able to confirm what temperature corresponds to what output voltage with the sensor connected to the aux input and grounded?

Thanks again guys !

[Patriq]

Christmas comes early at Autosport Labs!

This requires a hardware modification. On the V3 board there is a pad near the processor labeled "AUX". We STRONGLY suggest you build a signal conditioning circuit to place in front of the AUX input to protect your precious processor! you have been warned!

Brent !

1. When you say there is a pad labeled "AUX" - is it the one I have boxed with orange in the enclosed image ? Or should I just solder a wire to the pin on the processor and run that wire up to the proto-board ? EDIT: Ignore this - the board was clearly marked AUX. I must be blind.

2. You mention that one should mount a plug at the end of the encasement for bringing in the signal. Couldn't one just snap one of the leads for the molex and bring in the signal at the same position on the molex as on the V4 board ? EDIT: Embarrasing - Shows that you should do your homework - more than one time. I now found that V4 has two more pins on its Molex. Well - I'll use one of the Molex pins I won't be using anyhow.

3. Any favourable point to pick up +5V for the signal circuit board ? Could it just be the Vref pin on the Molex for the TPS ?

[DannyP]

Since you answered the first two, I'll help you with #3. Yes. That is where I grabbed mine from.

[brentp]

Patriq: You got it!

[Patriq]

Here's what I did. I'd be glad if anyone checked it for me.

Soldered up the circuit previously mentioned on an experimental board. First photo is of it.
It is wired as the text says. Not too pretty, but it should work. I jumpered the components with snapped of leads - but solder eventually flowed over the bridges.

I picked up +5V from where the MAP-sensor otherwise would be. It had a vacant slot.
Sensor signal in I took from one of the pins on the Molex. I removed one of the pins from the pcb. When I removed the pin with the solder iron the plastic in the Molex melted slightly. Therefor the pin doesn't rest solidly in the molex. It could be good enough as it is, but I will add som glue to really make it stick. AUX in is wired to the slot on the pcb, and ground to the pin on the molex where it is soldered on the backside.

[Patriq]

More photos of installment.

[Patriq]

Ok.
I've now started to test the aux input with my V3 board. I simply put the sensor connected to the aux input and read the temperature corresponding to the voltage reading for each bin and entered it from 0dgsC to 99dgsC. It took a little while, but was interesting to follow.

I then tried it out with the configurable outputs. I set output 1 to activate with AUX inverted at 60 degrees C, and output two to activate with AUX inverted at 85 degrees C. Both activated properly. The red "lights" in the configurator software was lit, and I confirmed that output pin 1 and output pin 2 had ground after the AUX had reached 60 dgs and 85 dgs respectively.
But..... after temperature was lowered below 60dgs , actually down to 30 dgs - both output 1 and output 2 was still active.

Shouldn't they have come off ?

Other than that it works flawlessly it seems so far.