Finding the right Power Supply ... please help

Other Hardware Motors, Mechanics, Power and CNC
1

Hi, thank you ahead for dropping by. I'm making a 3D printing nozzle for a design project (later will be attaching to the studio's robot arm). I started off with basic arduino kits and already ordered the following list..

and lastly the arduinUNO itself

I used my classmate's 12V 10A adapter to test the arduino - solenoid air valve. by connecting arduino, diode, 10k ohm resistance, TEP102 trasistor, the valve, push button, LED, etc
According to this diagram

ps : instead of TIP120 I am using TIP102
instead of 1K resistor I am using 10K resistor
instead of 1N4004 diode I am using the one that I have ( may be 1N4007 or 1N4001 )

Question 1 : My assembly of the solenoid valve is correct ? ( I don't want to burn my chips... I have tight budget.. )
Question 2 : What kind of Power Adapter should I buy. I have no idea at all.. I see some online are 12V, 24V, 36V, with various Amp. Will be plugging to UK wall. 240 V

Will this work?

Thank you in advance !!

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2

You have a variety of voltage requirements. A 12v supply and a number of switching regulators would do what you need. The current rating does not appear to be large, a couple of amps. Safer to go for a bit larger.

12v will work the Arduino but the regulator may over heat. Use switch mode reg to bring it down to 7 to 8v. You could use the regulator to set to 5v and feed it straight in but using the onboard reg would be safer.

The servo needs less than 7v so another regulator required.

You don't say what voltage the steppers are so can't comment on supply.

Weedpharma

3

Hi thank you very much for your reply, I think the stepper and big easy driver board together needs 12 volts..

So in conclusion, if I buy 12V adapter, I do not need to lower the volts for
2: stepper 12 V
1: valve 12 V

but I need to somehow lower the volts for
1: servo 3-7.2 V
1: arduinoUno 5 V

.. is that so?
and what exactly the amp should I need... I found my friend's 12V 10A power supply makes his UNO abit hot..

I am looking into 12V 5A and 12V 6A,, is that a good idea?
These 2..

http://www.amazon.co.uk/JnDee-Supply-ADAPTER-Transformer-Powering/dp/B0086DE6FI/ref=pd_sim_sbs_diy_3?ie=UTF8&refRID=06DE7E4RAP8F1Z7J3YJN

Thank you so much, appreciated your help ! :slight_smile: :smiley:

4

A 12v 10A will not cause any more heat than a 2A supply. The Amp rating is what it is capable of, not what is is supplying. The heat is due to dropping the voltage from 12v to 5v, and this is done by dissipating the difference in heat.

P = V x I

= 7 x .2. Allowing current draw of 200mA
= 1.4 W

If you drop the V supply to 8v, the voltage in above becomes 3v and power drops to 0.6 W.

A 5 or 6A supply should be ample.

Your summary of voltages is correct.

Weedpharma