Control your motors with L293D

thanks.

thanks.

nice

any information about L298N H-Bridge

anything else than its data sheet…

**Just one more question, **
Which diodes should I use ?

would it be possible to have

would it be possible to have a second power source generating 9V but limit the power input to the chip to 4.5V using a voltage regulator ? i am asking because i need to use a second power source at 9V but the L293D gets realy hot at just 4.5.

Yep, having a second source
Yep, having a second source will work, with the grounds tied together. I think Vcc1 is meant to be a 5 volt supply, while Vcc2 is to run the motors, which is suppose to be anything from 5 to 36 volts if I remember the data sheet corrrectly.

Molex connectors

Those are Molex KK connectors. Commonly used in PCs for fan power connetions (3 pin version).

 

What about controling 3,6V DC motors?
I read the datasheet and I’m afraid to understand (sorry, I’m french and my english is poor…) that the H-Bridge can only be used on motors with at least 4,5V voltage. Could you confirm? Second problem, my motors ask about 1A per motor, and the H-bridge can drive currents of up to 600 mA, so I’m afraid the motor ask too much and kill components, right? The L293D seems to be better to resolve that second problem, right? Has the L293 to be powered separatly from motors? Is it possibe to power it through Arduino at 5V? Sorry for all of that question, I’m new in electronics/robots…

I have used the L293D on a
I have used the L293D on a Picaxe28x1 board with 3V motors. Since the L293D eats up about 1V, feeding it 4,5V will work, because it would end up being about 3,5V. If 600mA is too low, take a look at the L298. There are separate power pins for the chip and the motor, but there is nothing wrong with connecting them to the same power source, as long as the power is within the specs of the L293D and the motor. I wouldn’t recommend using the 5V output from the Arduinio for powering the motors, since I don’t think you can draw that much power from the pin. I tried using it for two servos once and it couldn’t deliver the power.

Minimum voltage/maximum current ratings

Yes, you are correct, the minimum motor supply voltage for the L293 (and L293D) is 4.5V. I’m having similar problems with the L298 and a car chassis that uses motors that go way too fast at 6V – they start to turn at about 1V.

As for the current, again, you are right . The L293/L293D will only supply 0.6A, while your motor requires 1.0A. The L298 is able to supply more current, up to 4.0. Once again, a minimum motor supply of 4.5V.

It is always best to keep your motor supply separate from your logic (Arduino, PIC, etc.) supply. Just connect the grounds (0V) in one place. Motors will draw large currents and cause voltage variations and noise on the power supply. If the logic is powered separately, then there’s less chance of trouble.

Thank you very much for your
Thank you very much for your replies! It’s more much clear for me now. So I’m going to study what the L298 can give to me…

Hey Sir, can you please let

Hey Sir,

can you please let me know if the l293d works only with PWM or if it can also be used with an SPDT switch.

Thanks in advance.

You can use a switch

Yes, the chip will work with a switch, but of couse you would not get any speed control. In fact, there wouldn’t be much point in doing it that way – you could simply connect the motor(s) directly to the switch. But, if the switch is too small to take the current of the motors, of if you want to have long wires to the switch, or for some other reason, you could generate the logic levels that drive the L293D from a switch.

 

I’ve just checked my l293d

I’ve just checked my l293d and how low can you go on the vcc2. I have vcc1 = 5V and hooked the vcc2 to regulated power supply and went down as low as 2.7V. Below that motors stop. I have 3v motors (tamiya double gearbox mabuchis) and I wondered whether L293d can be good to drive them. I think I’ll use this solution 5v fed through a diode to vcc2 giving 4.3 V and pwm not exceeding 190/255. This gives ca 3.0V rms relative to ground on positive motor terminal. The actual voltage across two terminals is higher (so it seems not the rule of thumb that l293d eats up 1v off vcc2 - depending on how you measure it, but in worst case it eats almost nothing - i checked that on the scope and peak-to-peak voltage on the motor is almost the vcc2, at least in the 3-4.5v voltage range, where I checked it).

And I thinkg the diagram on top of the page should indeed be corrected, as powering motors from the same voltage the uc is powered is asking for trouble. Not every controller board uses big 7805 1A regulator. Some have 78l05 or other tinier SMD versios, which will not handle motor load.

According to the datasheet
According to the datasheet that Sparkfun links to on Page 1 it states High Impedence Diode-Clamped Inputs. Am I missing something? http://www.sparkfun.com/commerce/product_info.php?products_id=315

Yes, “input” would be the
Yes, “input” would be the word missing. The flyback diodes are placed on the outputs, around the load to reduce inductive spikes. The 754410 has diodes on the output, but from what has been said these are only rated for ESD clamping, rather than for inductive kickback though they still might provide some protection.

MCU Code for PWM
Hi, I am unable to open the sample code. What program is compatible in opening it? I am using MPLAB to create the code for my microprocessor and am using the PIC18F1220. The h-bridge I am using is the L293DNE but have added diodes where they are needed. I will need to use PWM as I am driving a twin motor gearbox with differential drive. Any advice would be greatly appreciated! Thanks!<o:p></o:p>

This is Arduino specific
This is Arduino specific code. It is similar to C but with some slight variants. You would need to download the Arduino Development environment from Arduino.cc

MAJOR UPDATE
I´ve made a major update on this. It is simpler, more accurate according the datasheet, and now I mention the use of a voltage regulator, capacitors and unregulated power supply.

Good stuff
Pretty cool additions, and better clarification, looks good!

Thanks :slight_smile:
Thanks :slight_smile: