Society of Robots - Robot Forum

General Misc => Misc => Topic started by: Admin on April 23, 2009, 05:25:33 PM

Title: Axon improvement mod, need test volunteers
Post by: Admin on April 23, 2009, 05:25:33 PM

I've noticed on my Axon that as the battery gets really low that my Axon will reset often. For example, if I have a 6V battery and its say low at 5.5V, and then suddenly I turn on a lot of servos, the Axon will reset.

This is normal, but I have a mod idea I'd like to test that in theory should allow the Axon to handle even lower voltages without resetting.

It involves soldering a small SMD capacitor between ground and 5V (on the ADC line under the board). Its like 5 minutes of effort.

If you have:
solder (RoHS preferred, but lead-based is ok)
soldering iron capable of 380C or higher (no cheap irons!)

then just send me your mailing address. I'll mail you a free capacitor to try out in the next few weeks.

Solder it on and go about building your robots like normal. Then just report back whether the Axon works fine or if it did anything weird after a week of using it or so.

Title: Re: Axon improvement mod, need test volunteers
Post by: airman00 on April 23, 2009, 05:27:42 PM

what value capacitor, I might have one lying around

Title: Re: Axon improvement mod, need test volunteers
Post by: Admin on April 23, 2009, 05:43:17 PM

It must be a tantelum capacitor. I haven't yet decided the capacitor value yet, but I doubt you have one of those.

I had bought caps already . . . Mouser said it was 22uF, but the datasheet is 2.2uF. So gotta go back and order new caps . . . sigh . . .

Title: Re: Axon improvement mod, need test volunteers
Post by: TrickyNekro on April 24, 2009, 05:29:38 AM

I'll try it out.... But hey.... I can find a lot of tantalums no worries....
I know the south Greece supplier.... :p (he cooperates with mouser, digikey, EBV......)

Title: Re: Axon improvement mod, need test volunteers
Post by: Admin on April 24, 2009, 08:13:49 AM

I ended up deciding on a 10uF tantalum, 0805, rated at 16V and ESR of 6 ohms.

Title: Re: Axon improvement mod, need test volunteers
Post by: Admin on September 06, 2009, 08:41:38 AM

I tried this about a month ago, and have been testing like this since. Definitely a huge improvement when Sharp IR rangefinders are used. I used 5 (all that I own) and there was still zero noise in the 5V power supply.


edit: clarified that no noise was in 5V line

Title: Re: Axon improvement mod, need test volunteers
Post by: Webbot on September 07, 2009, 01:57:57 PM

Are you soldering caps directly to the Sharp IR board? If not - you should  ;) These beasts are current hungry.

Title: Re: Axon improvement mod, need test volunteers
Post by: Admin on September 07, 2009, 02:54:14 PM

Quote from: Webbot on September 07, 2009, 01:57:57 PM

Are you soldering caps directly to the Sharp IR board? If not - you should  ;) These beasts are current hungry.

Nah, thats too much effort :P