I need some advice on using the HW-130 Motor Shield. I am currently powering it with 10AA or 15V using only the external ports (EXT_PWR) on the shield, and the entire setup consists of the base Arduino board, a Sensor Shield v5.0 on top, and the HW-130 Motor Shield on top of that. It's a bit stupid, but we kept the middle board so there would be "easier" access to the TXD and RXD pins, which we used to connect an HM-10 Bluetooth module onto.
From there, we maxed out the rest of the ports with 4 DC motors and added 2 micro-servos. The 4 DC motors with wheels attached works fine, but now comes the problems.
Adding on some load to the servos for actual use, we found that it occasionally seemed to take too much power and the Bluetooth module would just shut off. It happened sporadically, but it was either the other servo jerked while the first was in use, or inputs tried making both move at the same time and that killed it.
I've found that the Motor Shield was intended to always have power coming from the Arduino jack, but since the project I'm planning to build will be mobile, that won't be possible. I suspect this could play a part in the problems we've been having, since connecting a jack to the Arduino board seems to fix the aforementioned problem.
Any help would be appreciated, and I will happily provide extra information if needed.
I hope you're not powering any servo from the 5volt pin of the Uno, or from the 3-pin servo connectors on that L293D shield (which also gets servo power from the 5volt rail).
I assume you're not powering the Uno directly from 15volt.
At that voltage you can't power anything from the Uno, including the BT module.
I assume you did not directly connect the RX pin of the BT module to an Arduino pin.
I assume you know that connecting the BT module to pin0 and pin1 of the Uno has it's limitations.
I assume you know an L293 is old technology. That chip can only power tiny motors.
Common yellow car/wheel motors and a 15volt supply is a big NO.
Leo..
I didn't use the pins of the board specifically, but instead the middle sensor shield.
I was not aware L293 was old. This is a project for a Pre-Engineering 20 class.
It appears to be functional, but I'll keep the last warning in mind. I'm just trying to figure out if there's any way to still use the HW-130 shield with only an external 15V supply as opposed to plugging into the jack.
Thank you for your advice.
Depends on your shield. Most of them have a jumper, which when removed isolates screw terminal motor power from the Arduino. Google "Adafruit motorshield v1" for the full specs. Don't confuse with v2, which is the improved version with more modern mosfet drivers.
Leo..
I have the V1 with the switch, but from what I researched, the only way it can operate properly with servos attached is by powering the bottom board with the jack wired to a computer, since the servos draw power directly from the arduino board (that's supposed to have 5V of power connected through the jack). Do you know of any power alternative that would work in the same way?
Thanks, DN
Powering the servos from/through the Adruino is a design fault on those v1 boards,
which they stupidly carried along on the v2 boards.
Small SG-90 servos draw 650mA peak every time they start moving. One servo is already overloading the Arduino. The servos should be powered from a separate 5volt supply, with only signal and ground connected to the Arduino.
That shield can't power those yellow motors with a 15volt supply either.
Normally 8-9volt is used to keep current within the L293D limits.
Leo..
Thank you for the information. We ended up just plugging a power bank into the board. It worked alright even with the 15V, though it definitely seems to be wearing the system as a whole out.
