l293d shield pinout

[kartable]

Hello,

I will have to drive 2 s90 servo motors in a project and I have purchased a L293d shield for that. Problem is I can't find the pinout to connect to my Raspberry.

The I/O numbers apparently refer to those of an Arduino, but as I have no Arduino and I never had one, it does not help.

Can I use 9 and 10 connected to GPIO 4 and 17 for instance?

Reference 1: https://www.instructables.com/Adafruit- ... hield-Use/
Reference 2 (in French): http://tiptopboards.free.fr/arduino_for ... p?f=2&t=37

[pcmanbob]

If you have purchased the L298D board shown it is specifically design to be plugged directly in to an arduino and is not directly compatible with the pi gpio,

It may be possible to interface it with the pi gpio but it would mean looking up each function of the pins on the board
and then working out if the pi can supply the required interface/signal,

you will also have to do signal level shifting in both directions as the arduino gpio works at 5V were as the pi gpio works at 3.3V and will be destroyed if you connect 5V to it.

So you will probably have to build an interfacing PCB with all the required components on it.

[kartable]

I did not see it as complicated. A Raspberry can drive one servo motor directly, but here I have 2 so I needed something in between. Would you have suggested something else than a L293d?

Now is it a problem to work with 3.3 V out of the Pi to the L293d? I will probably use 6 or 9 V anyway to the servo motors.

As I said, I don't know Arduino and I can't compare the signals from the Pi. If I install the arduino IDE on the Pi, it should be done easily. Am I wrong?

[B.Goode]

I will have to drive 2 s90 servo motors in a project and I have purchased a L293d shield for that.

How is an H-bridge chip/board necessary or helpful in controlling a servo?

[pcmanbob]

The board you have purchased not only controls 2 servos ( which the pi can do directly from the gpio anyway ) but also 4 DC motors or 2 stepper motors which is the L298D bit of its title.

You would not use an L298D to control servos anyway even if you were using the board you have.

The problem is you have purchased an board that is not directly compatible with the pi because its designed to work with an arduino, that's what's making it complicated.

I suggest you do a web search for how to drive a servo using a raspberry pi....

example https://www.youtube.com/watch?v=xHDT4CwjUQE

[ghp]

As kartable already mentioned you can drive a servo direct from GPIO, not needing this board. It will probably help to connect an external power supply for the servo.

The schematic for this specific board is https://cdn-learn.adafruit.com/assets/a ... -schem.png
It matches the image found in your reference.

I would guess that - although logic voltage of the board is 5V - the inputs on the board can be driven by 3.3V GPIO from RPi.

When driving motors, then the following applies:
The board uses a shift register to switch the driver input signals. So you will need to handle the shift operations too. For the shift registers, you need to connect the DIR_EN, DIR_CLK, DIR_LATCH, DIR_SER too

The arduino code for this board is in https://github.com/adafruit/Adafruit-Mo ... d-library/
It will help to match pinouts to the schematics and to understand the shift register.

[kartable]

The board you have purchased not only controls 2 servos ( which the pi can do directly from the gpio anyway )
[...]
I suggest you do a web search for how to drive a servo using a raspberry pi....

I have already used my Raspberry to drive a servo. That's not a problem... Here I have 2 and I won't drive them directly from my Pi.

[B.Goode]

The board you have purchased not only controls 2 servos ( which the pi can do directly from the gpio anyway )
[...]
I suggest you do a web search for how to drive a servo using a raspberry pi....

I have already used my Raspberry to drive a servo. That's not a problem... Here I have 2 and I won't drive them directly from my Pi.

"Here I have 2 [servos] and I won't drive them directly from my Pi."


Why not?

(Knowing what problem you are trying to solve may assist in providing an appropriate solution... )

[pcmanbob]

Then I suggest you use an add on board specifically design to drive servos from your pi like this one from pi hut

https://thepihut.com/collections/raspbe ... pi-ada3416

[kartable]

Then I suggest you use an add on board specifically design to drive servos from your pi like this one from pi hut

https://thepihut.com/collections/raspbe ... pi-ada3416

Thanks. That would probably be the best solution if I would stick to using a Pi. But I will switch to a NodeMCU, given that I have one unused in a drawer