Show Posts
Pages: [1] 2
1  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: July 01, 2014, 12:44:23 am
The basic idea. Data lines from Arduino to Servo Driver are not shown.

Hey steinie, hope you're doing good!

Where would you break the circuit and put the Amp meter (Red&Black) at?

At the servos pwm signal lead?

Or from the Vo coming from the LM323 to the Servos Vin?


Regards
2  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 28, 2014, 08:25:00 pm
Quote
and a TS7806 (instead of the 7805).

You can use a small diode like below to increase the 7805 output to ~5.7v for better servo performance.



Vin (battery): 8.31 V
Silicon diode: 1N4148
Vout: 4.95 V

Following this polarity:
http://en.wikipedia.org/wiki/File:Diode_pinout_en_fr.svg

As you can see, it's not increasing the 7805 Output to ~5.7V

Regards
3  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 27, 2014, 10:49:39 pm
Quote
where should it be placed?

"put a large capacitor between the arduino 5v pin and ground ".

You think a zener diode (4734) will work?

If you are talking about the 7805 regulator, I doubt a ziner diode would work. I use the little inexpensive diodes like below. Always good to have a bunch for experimenting.

http://www.radioshack.com/product/index.jsp?productId=2062587


Yes, I'm talking about the 7805 regulator and by the way just bought 1 zener just in case. I wasn't able to see your answer before I did it, though I think I may have any other diodes in my belongings.

Thanks
4  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 27, 2014, 03:43:44 pm
Quote
where should it be placed?

"put a large capacitor between the arduino 5v pin and ground ".

You think a zener diode (4734) will work?
5  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 26, 2014, 08:07:27 pm
Quote
Any special diode? There's no need for any additional capacitor, is it?

No, a small common signal diode will work. As to separate power supplies for the arduino and servos, with a proper circuit setup, a single power supply can supply both electronics and motors (very common in the RC world). You may want to put a large capacitor between the arduino 5v pin and ground to help protect the arduino from low voltage dips when the servos move. Remember to connect arduino and servo to a common ground.

Thanks again zoomkat. Just blew off the Arduino 5V and GND pins by my brains' short circuit a few days ago, though I'm still able to power it by the jack barrel. So instead of putting a large capacitor between those two pins, where should it be placed?

Regards
6  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 26, 2014, 12:26:06 am
The battery is the perfect voltage to connect to the arduino external dc power barrel jack but it is only 1000mAh so I don't know how long it would run your uC.. You might do a test. Charge the battery and run the uC to see how long it takes to get drained down to 7.6V. Then recharge it and do the same experiment using it to power only the servos. (run the arduino off USB cable).


Thanks again raschemmel for your great advice on this! I really appreciate it.

I'll definetely do that and see how long it takes for the battery to discharge and see if it fits for my purposes based on that criteria.
7  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 25, 2014, 07:59:03 pm
Quote
The problem is my battery can support both things running at the same time; it might not be the appropiate output voltage required for both of them.

It is considered bad practice to power a uC and an inductive load from the same source.

Thanks in advance raschemmel. So, is it strictly necessary to add another power source? Which device should I continue to power from the battery (uC or the servos)?

And if it's not much to ask for, what other power source would you suggest me to use for the component that needs to be isolated?

Regards

Quote
and a TS7806 (instead of the 7805).

You can use a small diode like below to increase the 7805 output to ~5.7v for better servo performance.



Thank you zoomkat, you're very kind. Any special diode? There's no need for any additional capacitor, is it?

Cheers
8  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 25, 2014, 07:58:29 am
Quote
My servos (both) running at full speed (1300 us, 1700 us) draw 260 mA (currently powered with 4.90V coming from the Vo pins from the TS7805)
Looks good to me. A larger voltage will just make the 7805 work harder and heat up. You can go to a 7-9 volt 3000ma for a longer run time.


First of all thanks a lot steinie44 for your kind response,

I forgot to mention that I'm trying to power both the arduino mega 2560 (directly from my 7.4V battery) and the continuous rotation servos from the Vo coming from the TS7805 (4.96V). The problem is my battery can support both things running at the same time; it might not be the appropiate output voltage required for both of them.

I'm thinking about getting a new one (11.1 V @ 1A Lipo Battery) and a TS7806 (instead of the 7805).

Do you think that'll work?


Thanks in advance


Regards
9  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 25, 2014, 06:15:24 am
Hey all!

Hope you're doing great!

I have a similar situation, unlike this case, I just need to power 2 continuous rotation servos (http://www.pololu.com/file/0J693/AR-3606HB.pdf) and the Arduino Mega 2560 R3 board with a 7.4 V @ 1000 mAh LiPo battery (https://www.sparkfun.com/products/10472).

I've been having troubles and I don't know what kind of voltage regulator I should use. In the mean time, I bought a 7806 but I don't know if it fits my drawn current purposes.

Any help will be great!

Thanks in advance

Regards

By the way using the TS7805 (powered by the LiPo battery at its Vin and GND pins) I got this measurements taken previously:

Vo: 4.94V @ 26°C (06/22 @ 05:30 am to 06/26 @ 01:30) which falls into the operational range.

My battery offers 7.4V @ 1000mAh (nominal) at full charge reaches up to 8.31V aproximately. Earlier today voltmeter was showing 7.60V.

My servos (both) running at full speed (1300 us, 1700 us) draw 260 mA (currently powered with 4.90V coming from the Vo pins from the TS7805)

Do you think I need another battery? Maybe one of 11V @ 1200mAh, or another voltage regulator?

Any help will be great!

Regards
10  Using Arduino / Motors, Mechanics, and Power / Re: Servo Driver and Arduino with One Power Source on: June 14, 2014, 09:13:45 pm
Hey all!

Hope you're doing great!

I have a similar situation, unlike this case, I just need to power 2 continuous rotation servos (http://www.pololu.com/file/0J693/AR-3606HB.pdf) and the Arduino Mega 2560 R3 board with a 7.4 V @ 1000 mAh LiPo battery (https://www.sparkfun.com/products/10472).

I've been having troubles and I don't know what kind of voltage regulator I should use. In the mean time, I bought a 7806 but I don't know if it fits my drawn current purposes.

Any help will be great!

Thanks in advance

Regards
11  Using Arduino / Installation & Troubleshooting / Re: Arduino Mega 2560 external power supply using VIN & GND fails on: June 13, 2014, 06:17:04 am
Rodolfo, did you connect vin and gnd at the same time than the usb connection?

(I did)

I wonder if this could be the problem.

No, I didn't. I connected only the external power source (LiPo battery).

But based on my experience, I can tell you that connecting both power sources at the same time (battery and usb) is not the problem. I did that before, I'm guessing that the problem might be the voltage supplied by the battery (in my case 8.21 V), so that the Arduino power summary (documentation) might be wrong in what external power source range (7-12 V) refers.

Or it might be the output current coming from the battery, but there's any warning about it,

Regards
12  Using Arduino / Installation & Troubleshooting / Re: Arduino Mega 2560 external power supply using VIN & GND fails on: June 13, 2014, 01:17:30 am
By the way, does anyone have an idea of which is the maximum input current allowed by these pins (Vin & GND)?
13  Using Arduino / Installation & Troubleshooting / Re: Arduino Mega 2560 external power supply using VIN & GND fails on: June 12, 2014, 07:20:09 pm
Probably the mistake could that i connected the usb and vin & gnd to external power supply at the same time?

I cant figure anything else...but i am new in arduino, so i am not really sure...

Hey man! hope you're doing good, same thing just happened to me a few mins ago. I hooked up the leads from my 7.4 V LiPo battery to Vin and GND pin headers, and some diode burned off. Battery had a charge of 8.23 V so it's still in the range (7-12 V), so I don't know why those pins are not working anymore.

I'll appreciate any comments on this.


Regards
14  Using Arduino / Installation & Troubleshooting / Re: Upload Timeout Error on Mega 2560 - Not Sure What Changed on: January 30, 2014, 08:34:55 pm
Hey I got the same problem, I tried to load different codes and some of them made it,

but by now I get to upload a code, but then this message appears, even though load is complete:

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer

Don't have any idea of how to fix it, please help
15  Using Arduino / Programming Questions / Re: Continuous Rotation Servo Problems on: January 28, 2014, 01:51:18 pm
Thanks Robin2 for your kind response.

I already fixed the problem, took me like an hour twisting the screw until it stayed still, also needed to open it to perform a better adjustment.

By trim pot I mean servo’s potentiometer access port (screw).

I though I had failed cause the servo was spinning only in one direction and not the other way around, possibly due to bad twisting and damage of the screw, but fortunately that was not my case.

Here is the datasheet and code, just in case.

http://www.chd.hk/UploadFiles/Att/2012111512192137.pdf

Code:
#include <Servo.h>
Servo RServo;
Servo LServo;
 
void setup() {
  RServo.attach(3);
  RServo.writeMicroseconds(1500);  // Stop
  LServo.attach(4);
  LServo.writeMicroseconds(1500);
}

void loop() { }

Regards
Pages: [1] 2