Need Help (verification) on my multi-motor Project (Stepper & DC Motor & Servos)

Hello All,

I am looking for some advice & guidance, as well as perhaps verification on my work so far, on a multi-motor project I am working on.

Background:
Specifically, I am looking to power 1 stepper motor, 1 dc motor, 4 servo motors, 1 end stop and an LCD screen + Potentiometer combo. To achieve this, I would like to use a singular 12V DC power supply source (Amperage yet to be determined), an arduino UNO board, 2 L298N Drivers (1 for the DC motor & 1 for the Stepper), and a PCA9685 driver for the servos. In the schematic seen below, is the point where I have managed to get myself to. To keep 12V for both L298Ns I have them connected in parallel to the power supply, and as said supply is 12V, I am using the 5V logic output on one L298N to power the arduino itself, and the other to power the PCA9685 logic. To provide 6V power to the PCA9685 for the servos, I am using a Mini-360 Step Down Voltage Buck Converter, also connected in parallel to the system. The end stop and the LCD+potentiometer combo are drawing their power from the arduino.

Firstly, I would kindly like to ask for those with more experience than me in this subject matter, if the set up I have come up with will work, and if not what modifications I need to make for it to work. Secondly, I would also like to ask if there would be a way to calculate the amperage for which the power supply would need to be rated for. The specs for the motors I am using are:

STEPPER MOTOR: 12V, 1.7A Rated current/Phase
DC MOTOR: 12V, 270mA draw current, 550 mA Stall current
SERVO MOTORS: 6V, 500-900mA draw current, 2,5A Stall current

At any given time, the stepper must be powered (and holding weight), but it will only move while no other motor is running. Conversly, the servos and the DC motor will only run one at a time, while the stepper motor is powered and static.

Thank you all in advance for any response !

For steppers, drop the L298N. Get a real stepper driver.
For the motors, go for a better solution. L298N is waisting voltage and power.
I don't think that the L298N produces any 5 volt at all. The Vcc 5 volt for that circuit is an input for the logic.
Please produce proper wiring diagrams, not "childrens pictures" as I name Fritzings.
To power all that, Your two cells look "not enough".

Firstly, could you elaborate on the "better solution" for the DC motor ? Secondly, the reason I went with the L298N for the stepper also, is that I've had bad experiences with dedicated stepper drivers in the past (like the TB6600), and also because from what reading-up I did online, the Vcc becomes a 5V 0.5A output pin when the L298N logic is powered from the 12V Vs input using the jumper connector, allowing easy powering (at least in theory) of the arduino and servo driver. In any case, I am not really after a recommendation as to better drivers, but rather how to work with the components I do have, unless of course said components will not work at all. Allthough specific recomendations for alternatives with associated wiring would not be unwelcome.

I can provide a proper schematic tomorrow, just thought this visualization was more universally appealing and up to the convetion, from what Ive seen in the forums. As for the battery, of course I am not planning to use a double AA holder...this was just the only battery available in fritzing. In fact as I said in my OP, I am not planning on using a battery at all, but rather a dedicated 12V power supply.

There has been written tons of explanations regarding the use of L298N. They're totally wrong for steppers and really poor for DC motors. I find no reason to copy all that old information. The info is there, just search.
Word sallad I don't try to use. I don't write any wiring out of Your words. Bad is that all You don't tell shows up directly in a wiring.

Ok so the L298N is a terrible driver, got it. Taking that at face value, would you be able to give me specific driver recommendations for a stepper and DC motor driver that in your personal opinion will do the job ? Afterall, if I am to produce a proper wiring schematic, but I am not use the L298N I will need something to replace them with. And of course if I am to use different drivers, that do not offer this (theoretically) convinient way of powering logic for the Arduino and Servo driver, how would I now go about power them ? Would I need to get 2 additional buck converters and run 5v parallel lines in the system ?

You need to supply links, data, about the steppers You want to use.
The same goes for the DC motor. Running one direction or both fwd and bwd?
If You would read the first topics telling how to get the best from this forum, how to use this forum, I would not need to spend time helping You to write the question in a way that helpers can use.
I've used TB6600 without any difficulties.......

Ive already supplied some data for the Motors that I thought would be relavant, although to be fair I did ommit that for the stepper the Phase Resistance is 1.86 ohms and Inductance is 3.55 mH ± 20%(1KHz). As for the DC Motor, it only needs to spin one way, but having the ability to spin both would be benefitial, if this can be achieved without too much hassle. Speed control is also required. The only reason I ommited this information was because the L289N already covered this functionality, and I was coming here to get my wiring checked, not realizing I would have to go looking for new drivers.

As for the TB6600, the one I purchased before turned out to be a lemon, and it was not inexpensive ~$11, although I guess not as expensive as they sometimes can be (like up to ~$25).

For the steppers You need a bit better drivers than the cheap 4988, 8825 due to the current. Properly used, 6600 would do fine.
For the DC motor a quite common driver would do. However the L298 will waist some 2 - 4 volts and the DC motor will not reach top performance.
Late here and time for sleeping.

Alright, thank you for your assistance thus far. I will update this thread tomorrow with a proper wiring diagram, and i'll try to rework the system with a TB6600. Cheers.

So you have two different stepper motors, because the first one calculates to 7 ohm.
Only the first one can be used with an L298, at low speed/torque, and with a hot L298.
Leo..

Thats the specs I got from the ebay seller I got my generic Nema 17 from. They are for the same motor, and as I am very inexperienced with these I honestly don't know which to believe

Screenshot_38

Time to measure the coil resistance yourself then.

Edit:
This seems to be a low-impedance stepper.
Some other sites list it as ~3volt, with phase resistances varying between 1.86 and 2.7ohm.
This stepper definitely needs a (chopper) stepper driver (not a common H-bridge) that can handle the 1.7A phase current. And a 12-24volt supply.
Leo..

I see, thanks for the information ! It would appear I definately need to replace that H298N then. Would the TB6600 be considered a chopper driver ? What about the A4988 and its derivatives/upgrades ? From doing some research, it seems those are the most common drivers used in 3D printers, where these Nema 17s are mostly used for.

Yes. Stepper driver work like (switching) buck converters. They keep motor current constant.
Make sure you give the driver enough supply voltage if you want torque at full speed.

Not rated for 1.7A, but can be used with a lower current if you don't need motor torque.

Nema17 indicates the size of the mounting plate (1.7"), and has nothing to do with motor specs.
Leo..

1 Like

I see, thanks ! And would there be a way I am assuming to limit the current at 1.5A when using a A4988 or derrivative ?

Yes. steppers like the A4988 and DRV8825 have trimpots to set the current,
and the TB6600 has dip-switches.
Also have a look at this page.
Leo..

As promised yesterday, here is the revised schematic done properly, this time integrating a A4988 (although the wiring doesnt seem like it would change much if it were replaced with a TB6600), and using a secondary buck converter to create a 5V circuit to power all the logic components separately. Any opinions on the feasibility and/or recommendations would be more than welcome.

V-in of an Uno needs 6volt minimum, because it goes through a 5volt regulator with a ~1volt dropout.
Leo..

Thanks Leo ! As I already have a 6V circuit I guess i'll just exchange the V-in of the Arduino to that. Other than that, does the circuit appear sound ?

Could also feed 5volt into the 5volt pin of the UNO.

Not enough time to go over the diagram.
Ground wires and power wires are normally not fully drawn, but replaced by symbols.
That makes it less cluttered and easier to read.
Leo..