Hello guys, I am trying to open 3 solenoids using a L293D (motor shield) and an arduino uno, i was trying to find wich pins i need to write in the code using Firmata (to be faster) but with all pins set on high, even from 14 to 19, I have 0 volts on M2 and M3, how is this possible?
Hi Emerald,
What voltage are you using and where does it come from? The L293D like the L238 loses about 2+ volts acress the output, better to use a FET based chip or module like the DRV series. Most drivers will drive one pin HIGH and the other pin LOW, so try all pins! Are you using one of those relay module of the Chinese type? I have used a couple and discovered that because of the opto input you may have to drive it LOW to make it work.
Show us your schematic and code, then we can see what's going on, etc.
hope it helps, regards.
Mel.
Cactusface:
Hi Emerald,
What voltage are you using and where does it come from? The L293D like the L238 loses about 2+ volts acress the output, better to use a FET based chip or module like the DRV series. Most drivers will drive one pin HIGH and the other pin LOW, so try all pins! Are you using one of those relay module of the Chinese type? I have used a couple and discovered that because of the opto input you may have to drive it LOW to make it work.Show us your schematic and code, then we can see what's going on, etc.
hope it helps, regards.
Mel.
I am using firmata and i tried all LOW and HIGH but i still have 0V
And i am using one from DK Eletronics
Hi Emerald,
Why not try the Arduino IDE or I really like Uecide, I know nothing of firmata or it's workings.. so can't help, we still need to see your schematic and code to see what your doing and if it's wll wired up right!! Without this no one can help yiu.
Regards
Mel.
I could but I dont know which pin I have to set HIGH so i cant continue with the code
Hi,
Then read the L298 or driver module data sheet? As I said before until we see your schematic (even if hand drawn) and code we can't help you, my chrystal ball is broken!! what driver are you using, and the solinoids too.
Regards
Mel.
This is the Datasheet http://www.ti.com/lit/ds/symlink/l293.pdf
This is the L293D http://www.engineersgarage.com/sites/default/files/L293D_1.jpg
Hi Emerald,
Sorry but your not giving us what we need, those links are for the L293 chip, not a driver board/module!! So what are you using?? what power do these soliniods need? we need to know.
Regards
Mel.
Solenoids are 12v but at the moment i dont need to use them since I have first to find out why M2 and M3 are always on 0V, what do you need?
Cactusface:
Hi,
Then read the L298 or driver module data sheet? As I said before until we see your schematic (even if hand drawn) and code we can't help you, my chrystal ball is broken!! what driver are you using, and the solinoids too.Regards
Mel.
I am using this one: Arduino Playground - HomePage
Hi Emerald,
That board is a nightmare!! it sends the instructions to the motors in a serial fashion! using the TTL chip in the centre. I could never get my head around it, and you have to use their lirbray too, it's gobbly gook!! Pull one of the L293's out and stick it on a breadboard, wire it up as per data sheet and try it that way.
Sorry but I can't help with this board. If you powering solinoids why not just use 3 FETS? it's simpler.. Google FET circuit.
Mel.
Hi,
For all to see;
Tom..... 
I have another problem, when i plug the shield with the L293D in the UNO i have M1 and M4 permanently set to HIGH, with voltage.
Even if i say in setup to set them low
const int buttonPin = 2; // the number of the pushbutton pin
const int ledPin = 13; // the number of the LED pin
int buttonState = 0;
const int motorPin = 12;
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(buttonPin, INPUT_PULLUP);
digitalWrite(motorPin,LOW);
(its just a part of code), with firmata i can coltrol them and set them to LOW and have 0v, but i cant with the code, what could be?