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You are correct! However, the error was on the schematic only. The circuit itself did contain a common ground for the 3v AND 9v power supplies. I've included a new schematic to fix the mistake. Good catch

Hi, My teensy has gone to the great recycler. I think I might have accidently touched one of the u controller pins with a 9V source, but I wanted to make sure that there is nothing in the circuit design that might have caused this. I am posting the schematic in the hopes that someone will give...

OK, I hooked Vcc to the +3.3v pin and it made the motors weaker. Not sure why. As I said, I am still experiencing some variation between motors, but it is much better than before now that the ground loop issue has been fixed. For the benefit of future readers, I am attaching a schematic of the...

Ok. I went back and learned how ground loops can add noise to a circuit. Based on that, I rewired my project such that the ground rail has one and only one path for the current to follow. I uploaded a new diagram that you can use to compare what I did before to what I did now. I tested the...

Hi, I know its been a few days, but I wanted to report back. "With all those motors hooked to the Teensy you may be drawing too much current" I understand your point, but the thing is I am only running one motor at any given time. It is strange that the problem is only on the motor "at the end...

Hi Guys, I want to report back on this issue. Its taken me some time, because I wanted to completely rewire all the connections and do other trouble shooting. FYI, for my H-Bridge driver chip, I am using break out boards for DRV8837. I am running a total of nine 5V DC electric motors with my...

Hi, I am trying to drive a bunch of 9V DC motors using some H-Bridge chips and my teensy. For my application, I need that the motors turn on and then off very rapidly when asked to by the microcontroller. I hooked up the motors, but I noticed that motor performance was very inconsistent, with...

Thanks for the input guys! I think I've found the problem. Nothing to do with the code or even the setup. It is the wires themselves. I used breadboard jumpers made in China. There is almost no copper in the core, and I am using a low voltage signal for PWM. I tried some actual solid core...

Hi Everybody, I have a project where I need to operate 9 LRA's with high frequency PWM (10K hz). According to the chart from pjrc, the 4.0 has 20 pins which are PWM capable: 0-12, 13-15, 18-19, and 22-23. I am using the USB serial, which I think eliminates pins 0 and 1. I am also using two I2C...