Internet of thing Digital Thermometer DS18B20

I purchased this ic a long time ago. Never had any chance of using it. But now the this small itsy bitsy integrated circuit is sending data on the internet.

You can check the link at http://abhaykant.com/mtb

It is connected on a custom gateway device.

The ds18b20 can take power in two ways. The circuit that i made is using the parasite power.


This time i used clear nail pail paint over the copper trace.

ds182b20 interface schematic
ds182b20 interface schematic

printed circuit board is designed in KiCad open source EDA tool.

 

UPDATE : 14 September 2018

Using nail paint as a substitute for PCB lacquer is a cheap solution. It should be avoided when making a rugged PCB. If their is a lot a mechanical vibrations and stress, then the nail paint will chip away leading to oxidation.

3.3 volt receiver signal level Interface board for esp8266-01

In my previous attempt at designing this board here. It was good. But to make the pcb smaller. I redesigned the pcb, i shifted some component here and there.

This PCB contains a 3.3v level shifter at the receiver pin.

Here are the schematics and pcb layout.

esp8266-01 interface schematics
esp8266-01 interface schematics
drill layout top esp interface
drill layout top esp interface
top silk layer esp interface
top silk layer esp interface
bottom trace esp interface
bottom trace esp interface
Top View of esp8266  interface board
Top View of esp8266 interface board
PCB bottom copper traces and pads
PCB bottom copper traces and pads

Etching time : 1 hour and 20 minutes

That’s very long time but the solution is used up. as this is a small board i don’t want to dip the board in new solution. Also i let the PCB sit for a while , and by doing this the etching is uniform and the i also found out that the traces are much sharper than before. So it is a good idea to let it sit for around 30 minutes before you shake the container. As i am doing this manually, so that is why it is a slow process.