1 warning light, 2 outputs?
 

Currently have the CEL hooked up as a warning light for coolant temp and shift light. You can only have 2 conditions for outputs, but I want to also trigger the CEL for oil temp and pressure. Can I just wire the CEL to both outputs or will I run into issues when just one of them turns on.

i dont see how youll notice a CEL light for shifting...

I put an extra bright LED in there. Its worked so far. Just want to add more functionality.

its just a ground, i suppose if it goes solid you'll know its some sort of issue of three.

So no issue running 2 outputs to one LED? I couldn't think of any, but wanted to check.

No problem.

i don't really see how it would hurt, but might wait to see what others say. the outputs are just simple transistors that just toggle the output to ground.

Ok. Thanks. Its not really supposed to be a diagnostic light. Its more of an oh shit stop driving light.

As brain said, I think it's just OC transistors that are floating when open.

In case they are not, just put in some diodes isolating the outputs. That's definitely safe.

They are indeed open-collector transistors.

No need for a diode. The functionality of a diode is inherent in the construction of an NPN transistor. You can parallel as many outputs as you like in this manner.

What Joe said.

Thanks guys. Wired it up today, will test once my extra resistors and caps come in.

get an expander board, bro.

I have one bro. But its filled with circuits. And they all need stupid 2.49k resistors.

Work has 2.47k and 2.5k. And 2.51k and about every other damn resistor possible. But no 2.49k.

for a simple relay output?

you need a 1K resistor, a pn222222222222222 transistor, and a 1N40001 diode.


https://www.miataturbo.net/attachmen...ine=1455638836

No circuits are for inputs. Using nitrous 1 and 2 for my CEL.

Built circuits for JS4 and JS5 as inputs, which is why I need the resistors.

I have an ms3x. I'm using all of its inputs.

What type inputs? Analog? Are you going "Pat-nuts" with the pressure sensors?

Maybe....

F/R brake pressure
3 Map sensors
2 AIT sensors
Oil pressure
Oil Temp
Fuel pressure
Fuel Temp (through flex sensor)
Coolant pressure
Traction control adjustment input
Boost control adjustment input
Launch control adjustment input

I have a spreadsheet with everything

https://docs.google.com/spreadsheets...it?usp=sharing

if analog then all you need is 2 diodes and a 1K resistors for each...

otherwise, whatever ciruict you're builing. 2.49K and 2.5K and 2.51K all fall within the 5% margin of error of these things...

laymen's: close enough.


edit: looks like youre doing a temp sensor.

those other resistors you found are fine, you'll just want to measure whatever resistor you use and make sure to input the actual value as a bias.

the MS uses 2.49K that are 1% error ones, so pretty spot on. That's why they are blue. Otherwise all others are +/- 5%.

it's used for the 5vref pullup.

damn....