Practical Testboard for ESP32 and ESP-PROG

I newly bought an ESP-PROG and made a setup to test and debug my greenhouse control with breadbords and dupont wires. I had a lot of troubles with bad connections, so I decided to make a testboard with minimal use of breadboard and wires. Here is what I came up with.

This instructable is intended for those, who already have knowledge of ESP32, ESP-PROG and debugging with VsCode. I am not going into details about those subjects here. This is about hardware only.

If you need a tutorial about setting up your ESP-PROG, this great article by Simon Stuart on flowduino helped me to seamlessly do my first debugging.

https://flowduino.com/2021/09/02/debugging-esp32-programs-properly-esp-prog

1 ESP32. I use 38 pin NodeMcu-32S

1 ESP-PROG. Espressif

2 Mini DC-DC step down converter one 5V and one 3V3. The ones with about 98% efficiency

8 bit dil switch

9 LED. I have used 3 yellow, 3 green and 3 blue. Any color will do

2 trim potentiometer. I have used 10 K

8 resistors 10 K

9 resistors 330 R. If you need to turn on more than 7 LEd's simultaniously, use 470R

1 power socket 5.5*2.1-2.5 mm with solder pins

1 double side prototype board 7*3 cm (24*10 holes)

1 double side prototype board 8*6 cm (27*22 holes)

1 Dual row Pitch 2.54mm IDC 10-pin connector and socket

1 Dual row Pitch 2.54mm IDC 6-pin connector and socket

1 short lenght of flatcable

3 Single row female 2.54mm pin header 40 pin

1 Single row male 2.54mm pin header 40 pin

1 Single row male 2.54mm pin header 90 degree 40 pin

1 jumper

5 3 mm bolts, nuts, 4 short spacers and 1 washer

8 2 mm bolts, nuts and short spacers

1 piece of Plexiglass 13*14 cm and one piece 4*5 cm

2 small cable strips

Solder wires

All the above can be bought cheap on AliExpress

Cut one piece of plexiglass 13 * 14 cm and one piece 4 * 5 cm. Drill an 8 mm hole i the middle of the small piece for the power socket.

Fix your small piece to the big piece with a screw wing and drill 4 3.5 mm holes thru both plates. If you do not have 3 mm screws, 2 or 4 will do. Adjust the hole size acordingly.

Place your ESP-PROG and mark holes for the cable strips. One of them should be placed, so that it is up against the jumper sockets for power selection to keep the ESP-PROG in place, when you detach the USB cable.

Fix the ESP-PROG and drill a 2.5 mm hole for the stop screw. Cut 3 mm thread and place the washer and and the screw. The washer must be high enough to stop the ESP-PROG, when you attach the USB cable. If you do not have thead cutting tools, drill the hole 3.5 mm and use a nut instead.

Place the prototype bords on the big plexiglass piece and mark holes. Drill the 8 2.5 mm holes.

Now it is time for soldering. Place all the components on the 2 prototype boards as shown in the pictures. The 38 pin ESP32 come in 2 versions. 1 with distance of 10 * 2.54 mm and 1 with 11 *2.54. I always use 11, but if you have both, you can place 1 extra 19 hole socket up against the other. Place your ESP32 in the two strips before soldering to ensure correct distance.

In the IO strips, I have taken out pins for TX, RX and IO00 before soldering. They can be easily drawn out with a needle nose plier. I dont want to risk destroing my ESP-PROG by incorrect wiring to those pins

The internal power supplies, 12V to ESP32 board from the power plug and 3.3V from ESP32 board to IO board are 90 degree male connectors placed on the bottom side of the ESP32 board.

We are almost done. Attach the power wires. The ESP32 board to 12V from the power plug and the IO board to 3.3V from the ESP32 board. Fix the boards and the power plug plate to the big plate with the screws and nuts.

To make life easier, I have attached an image of the usable pins. This, of course, only works for 38 pin ESP32 development boards.

You now have a testboard with 3.3V, 5V and 12V supply. Connectors for 8 digital inputs, 9 digital outputs and 2 analog inputs. The LED's can also be used for PWM and analog outputs by changing light intensity. You will probably still need a breadboard now and then. Like I did for my greenhouse three DS18B20 temperature sensors.

The flat cables are quite easy to make yourself. You do not need any special tools. Only a vise and a pair of scissors.

https://startingelectronics.org/articles/IDC-ribbon-cable