Hi there! This is incredible forum! I was searching for some info here and on the forums on adafruit.com about the questions I have but couldn't find exactly the info needed.
Im using a Arduino Uno SMD edition. I have the motor shield from adafruit.com which basically has 2x H bridges (L293D) and can control 2 servos, 2 steppers and 4 DC motors. I only want to control 1 stepper motor. My motor is unipolar 12V 0.6A. I have a DC adaptor that I use to power it up which is 12V and 2A. And I also experiment with a NiMh battery - 12V 1.6A. The motor runs perfectly with the sketch Im using - I can control the speed, the directon , etc. What I am not sure though is if the voltage is ok for both the arduino and the motor shield. The motor shield can use anything from 2V to 36V from what I read on their site. But after running the motor for 2-3 minutes the arduino (or what seems to be a voltage regulator - Im not too sure actually if it is that) gets very very hot. I read on the forums here that it's normal to get hot and that if I use it with 12V it can get really hot. But Im not too sure what "really hot" means. Do you think my voltage is fine running the motor ? I will be using it for timelapse dolly system and it will be unfortunate if it stops after several hours of operation. I`ll need it to run for at least 6 hours.
Thanks a lot!
Unfortunately your finger is not a really good method of measuring "really not", as you'll generally think anything above 50C or so is "really hot" while for an electronic component, anything below 100C is not a big deal.
12V should be OK, though it is about the upper limit of what you want to send the Arduino board, ESPECIALLY if you powering other things from the board (like shields, external LED's, etc.)
However, it's possible your DC adapter is putting out more than 12V if it's the old-style "heavy" type (i.e., a linear adapter rather than a switching adapter).
Frankly, the best thing to do is to try to measure the temperature of the regulator. Many DMM's these days come with temperature measuring capability and a small thermocouple. Do you have one?
Also, if the regulator will stop due to overheating it will do so in a few minutes. It's very unlikely that it will stop after several hours.
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-Unfortunately your finger is not a really good method of measuring "really not"
exactly
-However, it's possible your DC adapter is putting out more than 12V if it's the old-style "heavy" type (i.e., a linear adapter rather than a switching adapter).
It's a small DC adapter from an external HDD actually. The same thing happens with the battery I`m using too. I haven't measured the power though. I have to do that to be certain.
-Frankly, the best thing to do is to try to measure the temperature of the regulator. Many DMM's these days come with temperature measuring capability and a small thermocouple. Do you have one?
I`ll try to find one
-Also, if the regulator will stop due to overheating it will do so in a few minutes. It's very unlikely that it will stop after several hours.
That's good. I`ll leave it for at least an hour to see if it stops running.
One thing to do is to put the 12v into the motor shield, but use a 12v->6v switching regulator to drop the voltage efficiently and plug the 6v into the Arduino board. I plan to do this when controlling 12v motors, though I'll need beefier H-bridges than the motor shield.
I'm thinking of using a TPS5430 chip from TI for the switching regulator, but I've not done the design yet. It turns out that TI sells an evaluation board for $10 that has all the design done. All I'd have to do is remove a jumper chip and put in a 3.3kâ4k ohm resistor (to set the output voltage to 6.25â6.5 volts, which is the ideal voltage range for the MC33269D-5.0 linear regulator on the Arduino board.
