isopod v2 connections

[scotty]

Hi, I am new to DSP hardware and programming and am reading all I can to learn as fast as I can. I have an Isopod V2 that I want to use for an autonomous robot (eventually line-following, obstacle avoiding, etc). First I just want to make the robot move, under battery power. I will be using two rc servos modified for continuous rotation.

From reading various posts in the forum, this is what I have gleaned so far. I will hook up a 9V battery to J1 pins 23 and 24 to power the pod. I will hook up a 6V battery pack to J5 pins 1 and 2 to power the servos. I will hook up the servos to J6 pins 1,2,5 and 19,20,23.
(1 and 19 are signal, no?)

Aside from how to get isomax to make them turn, have I got things hooked up right?
Scotty

[RMDumse]

Originally posted by scotty
I will hook up a 9V battery to J1 pins 23 and 24 to power the pod.

Yes, put GND to pin 23 and +V power to pin 24. But really a 6V battery made of 4AA's would probably work better and last longer. 9V "transistor" batteries have low capacity and notoriously short lives. Anything over 5.5V on the analog regulators is just wasted as heat. The only thing on the board that uses the 5V is the CAN bus chips, so your supply could even be as low as 4V and still be fine.

You want to use separate power for the board vs. the servos, because the servos can draw so much instantaneous power when they start, the can spike the 6V batteries lower than 3V, which will reset the processor board.


I will hook up a 6V battery pack to J5 pins 1 and 2 to power the servos.

Oh no. On IsoPod(TM) V2 there is no place onboard for servo power. (On IsoPod(TM) V1 we had full three pin connectors for the RC servo connections. But on V2 we condensed several connections into a single connector, and dropped the explicit power routing for the PWM to RC Servo connections. We offer an adapter board that does this function on a messanine board.


[QUOTE][B]I will hook up the servos to J6 pins 1,2,5 and 19,20,23.
(1 and 19 are signal, no?)

You could do this if you wanted, but you would be powering the RC Servos off the +5 of the board itself, and would be likely to spike the board power, and make it susceptible to spurious resets (or not, depending on your servos current characteristics).

Better to hook the +V and GND of your separate power for the servo to the servo connector, then hook from your signal pin (1 and 19 if you'd like, but I'd probably just use 1 and 3 so I stayed on just a single PWM unit.) and then a common GND between both the GND of the servo battery and the GND of the board, so the out flowing PWM signal has the required return path to GND.


Aside from how to get isomax to make them turn, have I got things hooked up right?

Close. Adjust as above. Maybe you want to look at our RC Servo Adapter board. At least the schematic, if nothing else, so you get the idea of what we did. Nothing too special about it, it is just wiring and distribution of signals in a form ready for RC Servos. In that case, though, lots and lots of servos.

[Dave]

Part of the connection is correct Scotty. Power for the IsoPod would go to the Vin (pin 24) and GND (pin 23) of J1.

A servo header cannot be plugged into to the pins of an IsoPod V2 without the use of the RC servo adapter we have available. The seperation of the connections as you've done would be the easiest method to try without the adapter. You are correct in that Pin 1 of J6 is a signal pin (PWMA0) that can provide the drive signal for a servo. The pin behind it (pin 2) is connected to the regulated 5 volt output from the regulator, that has produced that voltage from the 9 volt battery plugged into J1. This might cause some extra heat from the regulators if trying to connect a 6 volt battery pack in on the pins of J5. Back to J6, the GND of pin 5 would be good to connect to your servo somehow to provide a common refernce. Pin 19 (PWMB0) would be another signal pin to your other servo, however you would not have to skip using pin 4 (PWMA1) to drive a second servo if that were needed. Each of the 12 PWM pins can be used to provide a servo signal.

In order to have a seperate voltage supply for the servos, you might consider connecting the servo power wires directly to the postive 6 volt side, and connect the negative wire to both the servo ground wire and the ground of the IsoPod. It's a bit easier connection with the RC-Servo Adapter board, where the external battery can simply be plugged into the V= connection to power servos. Also, 9 volt batteries do not have a lot of capacity, so another 6 volt pack could be used for the IsoPod that would generate less heat in the regulator as well as last longer. Better still, using rechargable 4.8 volt packs in both cases, for the servos and for the IsoPod.

[scotty]

Thanks to both of you for clearing that up for me. Is the Isopod v1 obsolete and no longer available? I actually don't really need to control lots and lots of servos, and I sort of like the idea of the full three pin connectors.
Scotty

[nmitech]

scotty , I think the MiniPod will do the Job for you as well. But first, please checkout the board size to make sure.
http://www.newmicros.com/cgi-bin/store/order.cgi?form=prod_detail&part=MiniPod

If MiniPod is not fit for your application, then let us know. We can hand build the IsoPod_V1 as request.

[RMDumse]

And the IsoPodX(TM) and the ServoPod(TM) both also has the connector fields for RC Servos. It's only that we tried to really compress the IsoPod(TM) V2 into such a small space that brought us to loose those dedicated connectors.