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[ARDUINO] Spider dagu burn

hello everyone. 

I recently acquired a Dagu Spider malheureusment but I have a little problem that I would like to expose you BEFORE testing it myself. Because Dagu has cost quite expensive for my small ways! And my first test has not been very conclusive. So i have questions :

I'm using :

- 3 servos connected (D13, D12, D11). 2 Tower Pro MG995 and 1 Micro Servo 9g.

- 6 alkaline batteries 1.5 V LR6 - AA

 

.... the board heating  and no LED lights. Is this normal?

.... Am i using a bad batteries ?

..... Can we connect the dagu with an external power supply (like i'm using ) and connect it with the usb at the same time (while the card heated  I made a micro quick test and every time I sent data to the card I lost the connection "COM5") ?

i'm so lost ... please show me the light ^^.

ps : Everything is fine when i use 1 servo (c# program send degrees to arduino prog which move in case). But when i connect the battery with one or more servo ........ it's not the same ...

best regards

Sebastien

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ok, I tested with the right connection (while connecting two servos) and everything seems to work. Chance? I saw in the forum that the red LED is the one that tells me the bootloader on and it shines continuously. I connect all (ei battery + board + pc) and also seems to work with alkaline but I'll even get my NiMH batteries / lithium in the week.

I chose the wrong words in terms of physical units. As you said I'm newbie and I try to be careful next time! 

Thank you very much both of you, Oddbot and 6677 and if I may, I'll keep you posted on my progress! 

Regards

Sebastien

ok ! so i can choose batteries like 6*NiMH AA (R6) 1,2 V 2700 mAh Sanyo but not 6*alcalines 1,5 V 3000 mAh, because nimh deliver much more energy,  Is that it ? 

And the board which burn, it is because  I reversed the + and - of the battery. Sorry i'm a noob ' ^^

Can i connect the board with the good batteries AND connect by the Usb at the same time ?

thank you for having responded to me as quickly !

Seb

If you have connected the power the wrong way then chances are the board is dead however since the alkaline batteries cannot deliver very high currents maybe you will be lucky. All you can do is try connecting the batteries the correct way and see if it works.

The Spider controller can be powered just by the USB for programming if you do not attach any servos. If you have servos connected then you must have battery power turned on to program the board. This is because the USB cannot supply enough current to power servos.

Because you connected power the wrong way, even if there was no permanent damage you may have corrupted the bootloader. If you can get the lights to come on but cannot upload a new program then you should try re-burning the bootloader.

There is a tutorial here: http://letsmakerobots.com/node/35649

Well generally once you've burnt the board, thats it, dead normally. Oddbot did design it so he might know more about whether there might just be 1 particular chip which has died and can be replaced or if the whole board is likely totalled.

He would also be able to advise on the USB and battery simultaneously thing. It worked for my arduino nano, but the nano is not a spider.

Batteries. Alkalines are a bad idea. They are indeed low current. Current != Energy by the way, on a simple level you are correct but try to use the correct terms when dealing with an electronics based hobby. Current is very important to many devices, don't have enough of it then things shut down. Easiest example is the raspberry pi, its powered by a micro USB cable at 5v (as all USB should be) but the model B requires at least 750mA in an ideal world, a computer USB port is only 500mA, pi will attempt to boot but as soon as you try to do something like connect an HDMI cable (needs a fair bit of power to run the HDMI port) it crashes, not enough current to go around. Probably same situation with your servo motors, taking up way too much current and causing the CPU to reset. That said, I did run a raspberry pi and 2 DC motors from 6 AA alkaline batteries one time.

If the board is getting hot and there are no LEDs then either you have a short circuit or you connected the batteries the wrong way.

Alkaline batteries are not suitable. They cannot deliver enough current for the switchmode regulator which draws pulses of high current. You need to use NiMh or LiPo batteries.

No matter if you use batteries or an external power supply it must be able to deliver at least 7V and 2A - 3A of current.

This is a common problem that newbies do not realise how much current is required and that alkaline batteries are not suitable for robotics.