How do I feed the ServoDog?

[TJ Hvasta]

( yeah, yeah, from behind the fence).. The manual only says, 14vdc max.. I feed it with a 12vdc bench supply, but the heatsinks get really warm.. and the servos chattered a bit, so I cut off the power to it. Can I safely feed it with 12vdc, will it regulate to 5vdc for the servos or do I have to feed it with 5-6vdc? I have a 6vdc/5A wallwart I can use instead of the bench supply.

[dgtlpro]

Sounds like you have a ground loop with the bench supply. Also, how long of lead wire is on your servo?

If the lead is to long it could introduce chatter on the signal line.

I use a 12v 1A switching supply from an old network router and it does just fine.

[MikeZ]

TJ, I feed the Servo Dog with two power supplies, a 6v and 9v. I had them from a previous controller so I wired them up to use them both and they worked well. I feed the V+ and G (on the side connector block) with the 9v supply and I feed the 6v + to the S1 & S2 connectors on the sides of the servos and the - to the G with the 9v -. I believe the S1 was jumpered with the V1 and S2 was jumpered with the V2, and both jumpers had to be removed. I hope this helps.

[TJ Hvasta]

The lead from the power supply (actually a Midland Mobile Radio supply) is only 3' long.. the servo line is abt 12' long..

Mike, why the two supplies? One for the board, one for the servos? With the one supply, both the S1 & S2 jumpers are inserted.to power 1-4 and 5-8. It wasnt chattering but running very slowly from stop to stop.. then would pick up its pace again and re-sync..

[MikeZ]

Before using the Servo Dog last year, I used a Wizard 3 board from BPE, it used two supplies, and worked well. So I adopted this configuration with the SD after writing LOR about hook-up configuration, and they said it was a great way to power the servos. If you have some powers supplies available, I'd give it a try. I bought the 6v 3.3a power supply from Digikey and I think the 9v 2.2a came from there as well.

[dgtlpro]

TJ

The problem with your servo chatter is your 12' lead. If you are using inexpensive hobby servos then you might consider running your servo signal (G & S on the dogs servo outputs) the 12' as you have it, then if possible put 5-6 volts at the servo (as close as possible to the servo). I ran into the same chatter issue, timing and sync were off, until I applied power at the servo and ran the signal on a separate line. Managed to get it working with a 25' signal lead.

Edited August 18, 2012 by dgtlpro

[Ken Benedict]

You might want to meter the actual voltage from the Midland supply; some of them supply vehicle voltage, which can be up to 13.8v dc.

[Vic Fortenbach]

If the power supply is old - about 6-10 years, the caps inside the power supply may have dried out. Dried out caps tend to not filter the DC current/voltage well. Bad filtering of the current or "garbage" on the voltage output line will cause any electronic curcuit (including the Servo Dog) to do strange things when powered by this power supply.

[TJ Hvasta]

Thanks for the tips.. it wasnt really chattering, and not all the time.. I had three skulls (with 6 servos ttl) plugged into the SD. Of the six servos, only two were commanded, the other 4 were idle. As the sequence looped for approx two minutes, one jaw servo open, closed very slowly then would pick up in sync with the audio.. work correctly a few more times, then do it again.. Powered down, restarted it was fine for a couple loops, then it would slowly open/closed the jaw...

All these skulls, (actually fourteen 3-axis, 4-servo skulls) ran perfectly off a couple Lynx SSC32 controllers with this power supply (and longer cables) with no problems. The servos are HiTec HS45BB's.. Supply voltage 13.2vdc.. Caps were replaced 3yrs ago.

[dave carlstedt]

TJ, I feed the Servo Dog with two power supplies, a 6v and 9v. I had them from a previous controller so I wired them up to use them both and they worked well. I feed the V+ and G (on the side connector block) with the 9v supply and I feed the 6v + to the S1 & S2 connectors on the sides of the servos and the - to the G with the 9v -. I believe the S1 was jumpered with the V1 and S2 was jumpered with the V2, and both jumpers had to be removed. I hope this helps.

So, If I understand this correctly.... If i copy this arrangement, I will have two wires (one neg. from the 9v. supply and one neg from the 6v. supply) both going into the one G (on the side connector block.) connector. Pleas advise if this is correct...thanks

[MikeZ]

Dave, that's correct. I'm using both my Servo Dog controllers this year maxed out, and the set-up seems to be working well. I'm using Cat-5 servo blocks I made to feed my animatronics using a 25' cable, and so far there's no chatter with this set-up.

[Bernie]

Hello all,

I thought I would chime in on this and suggest a servo signal booster. You can make your own alot cheaper than what they sell them for at hobby stores. Go to this article http://www.servocity.com/html/boosted_servo_extensions.html and they explain why you might be getting servo chatter. Note : Place booster between extension wire and servo wire. In other words as close to the servo as possible.

[cgiambruno]

I am having the same issue.  However, my board does not respond in the sequencer under SD.  It only responds under the DIO32 channel.  The Servodog utility works fine.  I too get the chatter, then a reset.  It only does it during a sequence, and not with the servo dog utility.

[AndrewB]

TJ

The problem with your servo chatter is your 12' lead. If you are using inexpensive hobby servos then you might consider running your servo signal (G & S on the dogs servo outputs) the 12' as you have it, then if possible put 5-6 volts at the servo (as close as possible to the servo). I ran into the same chatter issue, timing and sync were off, until I applied power at the servo and ran the signal on a separate line. Managed to get it working with a 25' signal lead.

 

I'm two years late to this conversation, but this is the exact topic for my question.  We're just getting into animatronics this year with the ServoDog.  With your setup, you say you run power at the servo and signal on a separate line.  Do you not need to connect the servos to a common ground back at the ServoDog?

Edited August 19, 2014 by AndrewB

[AndrewB]

Dave, that's correct. I'm using both my Servo Dog controllers this year maxed out, and the set-up seems to be working well. I'm using Cat-5 servo blocks I made to feed my animatronics using a 25' cable, and so far there's no chatter with this set-up.

 

Mike, I asked this question of 'dgtlpro' as well, but since this thread is 2 years old I thought I'd ask you as well.  Do you need to connect the servos to a common ground back at the ServoDog with this setup?  Or do you just run a single signal wire from the servo to the ServoDog and power and ground at the servo?

[MikeZ]

Mike, I asked this question of 'dgtlpro' as well, but since this thread is 2 years old I thought I'd ask you as well.  Do you need to connect the servos to a common ground back at the ServoDog with this setup?  Or do you just run a single signal wire from the servo to the ServoDog and power and ground at the servo?

I started using these last year http://www.servocity.com/html/cat6_servo_extension.html#.U_OnSBag8Sw. They work great and have built in boosters. I'm using 25' cat 6 cables without a problem. I originally made my own extenders a few years ago, but they seemed to have a little noise. These are rock solid. You can also apply power at the animatronic end if you plan to run farther, supposedly 100' is the max. You will also need  male to male extensions at the Servo Dog end to hook them up.