can't make Endstop_1.3.1's signal detected by arduino UNO + have a weak LED's light

Hi,

I'm testing the Gen7_Endstop_1.3.1 on a breadboard. And I can't make it works fine.

I link the output signal of the endstop to an input belonging to an arduino UNO Board and I plug an external LED+resistor to an other arduino's output.

I use this little arduino code for polling and repeating the signal of the endstop to the external LED :

void loop()
{
   digitalWrite(outExtLed, digitalRead(InEndStop)); 
}

The endstop detects obstacle but the LED belonging to the endstop barely light up as there is only 200 uA through it. My external led don't light.

But if I unplug R3, making the endstop's led useless, the arduino detect perfectly the two state (with/without obstacle) and so my external led works fine.

I guess the endstop circuit design works fine so I don't know what I did wrong.(I use the 5 V alimentation of my arduino board as in gen7 the endstops are alimented by 5V also).

So if you can help me with that thanks ; )

Which signal voltages do you get?

The LED is fed with current/voltage from the signal, so it's not possible to give more juice without dragging the signal even lower. The given resistors are choosen carefully to give about 4V signal voltage (ATmega specs 3V as minimum for logic "1").

If you want a bright LED you'd have to add an amplifying transistor (and loose the K.I.S.S. principle somewhat).

---

Generation 7 Electronics	Teacup Firmware	RepRap DIY

I'm sorry I actually had a 10kOhm R2 instead of 1kOhm.
Now I got a 0/ 3.9V signal and a LED with a way better light.

Thanks