L298n shield and wemos mini

HI,
Strange issue here. I have the wemos connected to the L298n Hbridge shield to drive two motors to open/close two windows. I am using the 5V output from the 298 to power the mini. When 12V power is applied to the 298, I get 5V at that terminal on the 298 and 5V on the mini. LED on mini flashes. Problem is that the mini does not connect to WIFI. I have tried three different 298's and mini's but none work. However, if I disconnect the mini from 298 5v and ground and instead connect via USB to a computer, the connection to WIFI is accomplished but switches are not recognized. If I then connect the mini ground back to the 298 ground all switches are recognized and system is fully functional. Finally, if I connect a wire from 5v on the 298 to the mini and then remove the USB cable, wifi and full system functionality are maintained.

Any thoughts on why this might be happening as I am at wits end!

Good start however you should download the data sheet and check it out. Spend some time with it and understand what the pins are for. You will find it has a minimum logic voltage of 4.5 volts. I believe the WeMos is 3.5 volts. I did not find any pins that supply 5 volts to power other devices. A schematic would go a long way in helping us solve your problem, at this point we can only guess as we cannot see your project.

HI, I have attached information about the l298n and Wemos D1 mini that I am using. Also included is how my circuit is wired. I hope that this additional information will enable you to give me more thoughts on how to solve my problem

Scan.pdf (599 KB)

The WeMos draws high peak current of up to 400mA during transmit.
The regulator on the L298 might not like that with 7volt overhead.

Try a 470uF electrolytic buffer capacitor across 5volt/GND of the L298 module.
Leo..

Hi,
Welcome to the forum.
Please attach images as jpg or png, it is easier to be viewed on some platforms, and the image will be put into the post as as a viewable image automatically.
Your circuit diagram, needs to be on a fresh sheet of paper, using the data sheet and drawing connections does not make for a very clear diagram.
Layout makes 80% of a schematic readable.

Thanks.. Tom.. :slight_smile:

Thanks Leo. I will get a capacitor in the next few days, try it and report back. The spec on the L298N says the logic current is 36mA so you could be spot on.

Tom, thanks and I will do the format you suggest in the future.