Dawn Robotics Forum

I have just built the RPi Robot Camera kit. The camera, pan & tilt all work fine however when I try to get it to move the pan tilt head moves rapidly (shakes) and the whole thing crashes and reboots. Help.

Hi Phil,

First up, welcome to the forum. Secondly, sorry for the massive delay in replying. I still haven't worked out how to set up a notification for when there is a post awaiting approval, although I'm off to Google it after this...

With regards to your problem, it sounds like a power issue, as if the batteries you're using can't provide enough current. Can you please give some details about how you're powering your robot i.e. are you using AA batteries (if so how many, and rechargeable or non-rechargeable?), or are you using a USB power bank?

Regards

Alan

Hi this is second query relating to same problem however slightly different, I didn't think my previous query had come through to you.

I'm using fresh Duracell batteries (6), I did suspect power problem (see previous post) and tried connecting Pi to mains adapter and controller to batteries however I burned out the controller card!

Now replaced, Robot calmer no servo shaking when trying to move. It just moves (quickly) forwards briefly then the Pi reboots (however all power lights (camera, dagu Pi) remain on. The pan tilt servos work fine also camera, just as sooner as I try activating motors to move the robot the problem occurs.

Phil

Hi Phil,

Are the batteries you're using rechargeable, or non-rechargeable? Non-rechargeable will struggle to provide the current needed to the Pi, motos and WiFi all at once.

I would say that for reliability, you should use rechargeable batteries if possible. I have had the robot run off non-rechargeable batteries but runtime is very low (only 30 minutes approx) success depends on

• Batteries used - Duracell are a good brand, so should be ok
• Type of Pi - The new model B+ draws less current
• Type of WiFi adapter - the recommended Edimax EW-7811Un seems to draw less current than other WiFi dongles.

If you are using rechargeable batteries then I need to have a bit more of a think. If they're rechargeable, what is their capacity in terms of mAh?

Regards

Alan

Alan wrote:Hi Phil,

Are the batteries you're using rechargeable, or non-rechargeable? Non-rechargeable will struggle to provide the current needed to the Pi, motos and WiFi all at once.

I would say that for reliability, you should use rechargeable batteries if possible. I have had the robot run off non-rechargeable batteries but runtime is very low (only 30 minutes approx) success depends on

• Batteries used - Duracell are a good brand, so should be ok
• Type of Pi - The new model B+ draws less current
• Type of WiFi adapter - the recommended Edimax EW-7811Un seems to draw less current than other WiFi dongles.

If you are using rechargeable batteries then I need to have a bit more of a think. If they're rechargeable, what is their capacity in terms of mAh?

Regards

Alan

The batteries used were fresh Duracell (non rechargable), its a Pi B+ and Edimax dongle.

Hi Phil,

In that case I think the best thing to do is to try rechargeables (Duracell 2400mAh are good). In our blog post on battery life we were able to run a robot with a Model B Pi on alkaline batteries (Sainsbury’s Extra Long Life) for approx 50 minutes), but it was rubbish compared to NiMh batteries.

Out of interest, do you have the updated version of the kit containing a UBEC? (this should be included if you bought your kit after August).

Regards

Alan

Alan wrote:Hi Phil,

In that case I think the best thing to do is to try rechargeables (Duracell 2400mAh are good). In our blog post on battery life we were able to run a robot with a Model B Pi on alkaline batteries (Sainsbury’s Extra Long Life) for approx 50 minutes), but it was rubbish compared to NiMh batteries.

Out of interest, do you have the updated version of the kit containing a UBEC? (this should be included if you bought your kit after August).

Regards

Alan

Yes forgot to mention using the UBEC. I think maybe i'll invest in a power bank.

Phil