Hijacking the built-in LEDs for HM-10

[espruino-discuss2]

Posted at 2014-07-02 by Alex

Hi All,

Since LED1 LED2 and LED3 are the same ports as A13 A14 and A15, I was thinking if we could somehow plug something in to port A13 (for example) and light the LED1 if that something gave a high signal?

This is for use with the HM-10 status LED. It works with an external LED just as stated in the docs, but to have just one cable to the A13 would be great :).

Regards,

Alex

[gfwilliams]

Posted at 2014-07-02 by @gfwilliams

Yes, that's no problem at all - as long as you set LED1 to be an input first - either by doing digitalRead(LED1) or pinMode(LED1,'input').

I'd suggest using LED2 or LED3 though, as LED1 is flashed at startup - so is automatically made into an output (which might conflict with the HM-10).

[espruino-discuss2]

Posted at 2014-07-02 by Alex

Great thanks :) I was trying with the opendrain mode but I was afraid to damage the board so I figured I'd check first :)

[espruino-discuss2]

Posted at 2014-07-02 by Alex

Could I solder it to that pin (A14)? or is that a bad idea with the leds flashing on updating the firmware?

[gfwilliams]

Posted at 2014-07-02 by @gfwilliams

Problem is Espruino pulls up to turn the LEDs on, so Open Drain won't work :) In fact I guess you might find that it's the wrong way around for the HM-10?

If not, how about using a resistor? You'd have to work out exactly but something like 1k should be enough to light the LED (not brightly) while not causing any problems if it ends up 'fighting' with Espruino?