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Farangwithaplan

Advice on a cheap adjustable power supply

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I am just starting to play with electronics on Arduino / ESP boards and the like and am looking for an adjustable power supply say up to 12 volts. I realise Adruinio runs and 5v but I would like to play with stepping down. I don't want to spend a fortune as I am not building rockets but just something that will do the job I need. Also I hear the ESP boards are quite fickle on the power input. Some can only accept between 3 and 3.3 volts or their smoke escapes. Will this be a problem with cheap adjustable power supplies?

 

On the ESP boards, I could just select ones that are fed via USB if a power supply I need to do the job is very expensive. Any ideas on what I should be paying for something for a beginner unit?

 

Also, please excuse my bad terminology. Feel free to correct it is I have used any wrong terms.

 

 

 

 

Edited by Farangwithaplan

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Does it HAVE to be adjustable?

 

A cheap PC power supply can be jigged to run without a main board and should give all the voltages you need. Some will need a dummy load on the main 5V or 12V outputs to regulate correctly (enter 12V 21W car bulbs).

 

Certainly anything that can be remotely fussy I would be putting on a fixed power supply, much less danger of human error.

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For really cheap you can just solder (quickly) pig-tales on D-cells and wire-nut them in series...


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Have a dig around on youtube, I’m sure there are some cheap solutions rather than an expense bench power supply. I have been using raspberry pi for a few years. There are 5v 2.5-3.0A on aliexpress that can be had quite cheaply, but they have micro-usb, which may be fine for arduino nano.
 

I just started playing with arduino too, basic robots, they run from little 9v batteries, or 4x AA batteries. Checking on aliexpress, 75B will get you a power supply with a barrel jack for uno 3.

 

I have some nano boards which weren’t really comparable with Mac OS, along with some buck converters which will step down 12v to 3v, and some other arduino bits that I will never use. If you want them, PM me your address.

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17 hours ago, Crossy said:

Does it HAVE to be adjustable?

 

A cheap PC power supply can be jigged to run without a main board and should give all the voltages you need. Some will need a dummy load on the main 5V or 12V outputs to regulate correctly (enter 12V 21W car bulbs).

 

Certainly anything that can be remotely fussy I would be putting on a fixed power supply, much less danger of human error.

Crossy, I really don't know what I need. I have a lot of reading to do. I had to look up Ohms law because it had been so long since I had to use it. I just assumed that an adjustable 0-12 volt power supply would be useful to cover from automotive power to ESP boards at 3.3 volts. Methinks I have a lot more reading to do. The posts in this thread already have given me food for thought.

 

 

2 hours ago, recom273 said:

Have a dig around on youtube, I’m sure there are some cheap solutions rather than an expense bench power supply. I have been using raspberry pi for a few years. There are 5v 2.5-3.0A on aliexpress that can be had quite cheaply, but they have micro-usb, which may be fine for arduino nano.
 

I just started playing with arduino too, basic robots, they run from little 9v batteries, or 4x AA batteries. Checking on aliexpress, 75B will get you a power supply with a barrel jack for uno 3.

 

I have some nano boards which weren’t really comparable with Mac OS, along with some buck converters which will step down 12v to 3v, and some other arduino bits that I will never use. If you want them, PM me your address.

Thanks for the offer Recom. In the short term I have decided to go with the Lolin NodeMCU V3 ESP 12e based development boards. Mainly because of the USB power input as well as pin variable regulated input power, a 5v out pin when connected via USB and the built in WiFi. The multiple pin outs and the fact the board is ready to go out of the box all for about 150 baht per unit. That makes it a no-brainer for a newby like me. The board also works well in the Arduino IDE space and with Python.

 

I played with the Web Server script last night and it was quite intuitive.

 

 

 

Edited by Farangwithaplan

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44 minutes ago, Farangwithaplan said:

I had to look up Ohms law because it had been so long since I had to use it.

 

I still have to use the (very non-PC) ditty we learned as apprentices to remember the resistor colour code (I have trouble actually seeing the modern resistors, let alone reading the colour bands).

 

You know, the one involving persons of color of dubious parentage, non-consensual sex and the occupants of the Temple of Vesta getting bored (answers on a postcard ...).

 

My Arduino projects are mostly powered by battery packs or 9V / 12V wall-wart power supplies from Amorn.

 

  

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Crossy wrote: 'You know, the one involving persons of color of dubious parentage, non-consensual sex and the occupants of the Temple of Vesta getting bored (answers on a postcard ...).'

Sounds like the same one Aussies learned. You may have stolen it from us.

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11 minutes ago, carlyai said:

Sounds like the same one Aussies learned. You may have stolen it from us.

 

Probably required learning for all English speaking electronic engineering students of "a certain age" 🙂

 

IIRC it was Wireless World magazine that ran a competition to come up with a "new" version.

The winner was :-

Black Beetles Running On Your Garden Bring Very Good Weather.

 

Boring!

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7 minutes ago, Crossy said:

 

Probably required learning for all English speaking electronic engineering students of "a certain age" 🙂

 

or; since retired military electronics students, dittying (over a certain age) at the bar after work...

"BBROYGBVGW" 

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For Arduinos you can use an input voltage of 6 - 20V. And then on the Arduino pins you can get regulated 3.3V and 5V.

This is obviously only for limited power. If you just run the Arduino and an LED or two it works. If you want to supply lots of additional modules with the Arduino 3.3V or 5V that won't work.

 

I think with the ESP32 you have to supply 5V and then you they have a 3.3V converter on board,

 

It's important that the power supply is clean. Adding a big electrolyte capacitor is a good idea.

 

In general I suggest you browse a website like this https://www.es.co.th/

They have cheap and fast delivery in Thailand. And you can visit their shops in Chinatown. It's fun!

 

You should look for power supply. Then you will find i.e. things like this one for 66THB.

3-Terminal DC-DC Buck Converter 5.0V/1A, ±2% Input Voltage 7-26Vdc

https://www.es.co.th/detail.asp?Prod=017605771

 

Make sure you look at the datasheet, which can be downloaded for almost any product. There you will see suggestions about capacitors which you need. Then you can put something together like this. The parts are all cheap.

 

5V.thumb.jpg.574b66efb61962a20ad8bb698aef6637.jpg

 

Be careful with linear regulators. They get warm, sometimes very warm very fast...

 

In general I recommend you look at the Arduino forum. They have lots of tips and ideas about hardware, software, ideas, etc.

https://forum.arduino.cc/index.php

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Andreas Spiess is one of my favorites on YouTube. Have a look at i.e. this video:

 

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If you live in Bangkok northern area go to Zeer Rangsit (Airport Asia Hotel) there are some very good electronics supply places where you will find what you want.

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