2017. február 25., szombat

Quick and Dirty - SMD LED Tester

I needed an SMD LED tester for my ongoing project. Unfortunately the local parts store puts everything into a single paper bag without designation, so I wasn't able to distinguish between the red and the blue 0603 LEDs.
A Kelvin clip from eBay, two banana plugs, a 330 ohm resistor, some loudspeaker wire, and lots of heatshrink.
The resistor in the wire:

The finished "instrument":

First I thought that the shorter heatshrink on the clip's leg will designate the positive lead but later realized that it would be a great idea to put heatshrink onto the tips and in this small size I had red one also.

2017. február 18., szombat

Project 2017#1 - ESP8266 Programmer 1.

It's been a while I didn't write anything. It doesn't meen I didn't do anything, just had no time/lust to write.
Here is my first project in this year (to by honest I started it in 2016 but it is the time to finish).
I started to work with ESP8266, and as many of us I bought the NodeMCU 0.9 board (years ago to be honest). This is a great board, to begin with it, but I don't like to put such ready made boards with programmer, regulator integrated to put into my projects. I prefer to have my own regulator, bare chip/module, and some ISP interface.
So I decided to build an ESP8266 ISP based on the NodeMCU board. I chose the original NodeMCU 0.9's programmer on two reasons:

  • It use CH340G chip, what is in SO package. The later ones use CP2102 and I still terrified of soldering the QFN package (I will try it once, I promise)
  • It has the automatic programming capability (RST, GPIO0 pins), mens I don't need to push buttons when I start the programming sequence

The original programmer use 5V to power the CH340G:

At the time I started to work on this project, it wasn't clear if the ESP8266 is 5V tolerant, so I felt it isn't a good idea to keep it this way. So I redesigned the circuit a slightly.
Here is my version:

I was able to manage to put everything to a single sided board:

and etch, build it at home:

It works like champ with my ESP8266 projects.