Power Supply

Hi, I have just finished building a Kossel mini with heated bed and ramps 1.4.
I have also bought a smart controller to allow me to run without a laptop.

How do I power my Arduino when the usb cable is not plugged in?

I currently have 2 psu's to supply the 12v @ 5A and 12v @11A. (soon to be 1)
Do I need a another to supply 7v?
Can I take 12v to it from one of the above?
Is there a link on the ramps board I can enable?

Sorry if it's a daft question, I just cannot seem to find the answer anywhere.

[reprap.org]

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Power Supply with diode
If your board has a 1N4004 diode soldered in, do not apply more than 12 V to it. Original flavor Arduino Mega are rated to 12 V input. While Arduino Mega 2560 can take 20 V, it is not recommended."]

Did you solder the ramps board yourself or buy a kit?

Basically the arduino takes power from one the main 12v input on the ramps board, presumably ramps converts that down to a lower voltage for the arduino however. The basic end result is that the arduino and basic ramps functionality (I.e smart display) can be used with just USB power, but when your power supply is turned on, they use the main supply automatically, without interfering with the USB connection.

Hi, thanks for the replies.

@jaydmdigital , I will check but never intended to use more than 12v if I ran in parallel with one of the other supplies.

@RickM, I bought the all the parts ready assembled over a period of time from different vendors.

If I just have the usb plugged in, powered from the laptop, I can cycle through the menu's etc. on the display.
If I switch on the 12v power supplies I can also start the printer running and printing.
However, If I switch off the laptop, effectively unplugging the usb, the display goes off and the printer stops.

Is this normal?

I think you misunderstood. Can you verify if your RAMPS has D1 and D2 http://reprap.org/wiki/RAMPS_1.4#D1.2C_D2_-_Diodes The second image shows where they should be.

Quote
Bixx
Hi, thanks for the replies.

@jaydmdigital , I will check but never intended to use more than 12v if I ran in parallel with one of the other supplies.

@RickM, I bought the all the parts ready assembled over a period of time from different vendors.

If I just have the usb plugged in, powered from the laptop, I can cycle through the menu's etc. on the display.
If I switch on the 12v power supplies I can also start the printer running and printing.
However, If I switch off the laptop, effectively unplugging the usb, the display goes off and the printer stops.

Is this normal?

@jaydmdigital
I have D2 fitted but cannot check for D1 until I finish a print that is running.

Thanks for the reply, I am confident this will be the issue.

***Update***

Spot On !

Thanks, I will fit one asap

Edited 1 time(s). Last edit at 12/31/2013 05:25PM by Bixx.