Boe Bot Power

Rift

I was hoping someone might be able to shed a little light on this for me as I have read, and read, and read older threads but still don't have the answer I'm looking for.

Based of what I have read so far. The Boe I'm using is a rev C so it has the Vin/Vdd jumper on it. To my understanding this switch decides whether or not the on-board 5v regulator is being used or not. I have also gathered that servos generally want 5-6v but some users here have pushed them as high as 7.2v with no extreme degradation. Any further then that and you are likely to start melting things.

So basically the way I see this is that if I am running the battery through the on-board regulator I can safely use up to a 12v battery pack. However If I switch over to Vdd then I shouldn't be exceeding, to be safe around 5-6 volts. It is also my understanding that the more voltage the more oomph the servos will have. Now I am looking to squeeze as much as I can out of them but, I'm not looking to melt them either. So I am assuming that 6.5 volts would do the trick for me. Would I be safe running 6.5 volts into the Boe-Bot through Vdd?

I also can't seem to find a rechargeable battery pack in that voltage range, and am not sure what the next best thing would be. I have found a 7.4 volt battery pack but I'm going to assume that is to much, unless maybe I make my own regulator setup?

The bot will be running 3 servos (2 continuous and 1 normal) and a ping. Also possibly the AppBee with Xbee. Not sure yet if I will be using the later.

Also could someone clarify as to why the instructions for the Ping with bracket/servo kit instruct you to switch from Vin to Vdd? Is this to allow more power to the servos?

Any help in the matter would be greatly appreciated Iv sort of hit a wall with what the best route to take would be.

Thanks!

Mike G

The BOE spec is 6-9V; recommended 7.5V 1A.

The BOE BOT comes with a 4 AA battery holder. Any reason why you can't use rechargeable AAs?

The PING uses 5V (Vdd) because it is a 5V device. It has nothing to do with saving power, Vin and Vdd come form the same power source. Look at a Parallax Servo Controller (PSC) if you have special servo requirements.

I would use the BOE BOT as outlined in the manual until I get a feel for the robot.

Rift

I guess I have something confused here I was under the impression that switching between Vin and Vdd, switched whether or not the power is going through the 5v reg on the BOE. It was my understanding that switching to Vdd bypasses the 5v reg.

From what iv read rechargeable AA's are not recommended because they simply don't supply enough voltage. Unless of course you get the add-on expansion and run 5 of them instead of 4.

So something like this would be fine to run with the bot? Would it have to be set to Vin or Vdd tho?
http://www.sparkfun.com/products/9703

Mike G

Right Vdd is regulated and Vin in unregulated. A 7.4V 2200mha battery produces 5V on Vdd and 7.4V on Vin. If the jumper between the X5 and X4 servo headers is removed, you get Vin on the servo headers. The default is 5V. This is all in the manual.

Do not wire a PING to Vin.

John Abshier

Mouser sells a 1.6 volt AA rechargeable battery. I have used it with a BOE Bot and they worked well.

John Abshier

Rift

Despite reading the manual and reading several posts I had still been confused on the matter of what needs how much voltage and what jumper does what. This however is now solved. Thanks for the clarifications

John I checked mouser but did not see any 1.6v rechargeable AA's.

Were the batteries you were referring to these guys

http://www.depoteco.com/wordpress/wp-content/uploads/2009/04/nizn1.jpg

John Abshier

I am not at home but I think those are the batteries. I owe you an appology. I think it was Jameco where I got the batteries and charger.

John Abshier

Found it http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2115848_-1

Rift

John no need to apologies it was an honest mistake. I ended up finding them on amazon with the charger too. I had no idea before this that 1.6v AA's existed. Thanks for pointing me in the right direction.