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The platform the software runs on is the Wemos D1 mini module with an ESP8266 micro-controller. Each decoder has its own PCB to put together the hardware components required for its function.
The hall sensor is placed into a “holder” on a small PCB with a connector. A current detection circuit is contained on a PCB to create a single current sensor.

The original “EAGLE cad” files for the decoders, servo tool and sensors are together with the decoder software on Git.
I was requested to put here the link to the PCB-manufacturer I normally use. So, here it is:

Explanation PCBs

eltraco_to_pcb2.jpgThe PCBs contain more than one design. They can be separated with e.g. a proxxon table saw.

The Wemos module fits into two female pin-header strips. Orientation is with the USB connector to the left side for the decoders. For the servo tool the USB connector is at the bottom side. To verify the correct position it is advised to load the Eagle-cad files into the free version of Eagle-cad and have a closer look at the "board" presentation of the design..

Underneath the Wemos module other components are placed. The DC-DC converter lies over other components. The DC-DC converter is soldered onto a four pole male pin-header and than soldered onto its place on the PCB.

In general GND is at the left side of VCC+/5V+.

On the three pole sensor connectors from left to right the pins are GND, 5V, Signal. On the output pins of the LED switch decoder left is GND and right is 5V.

The bills of material of the decoders are on a separate user page.

The placement of the components can be found in the black and white pictures below.

DC-DC convertor

eltraco_dcdc_adj.jpgeltraco_dcdc_fx.jpg At left the back side of the DC-DC converter is depicted. This piece has a small potentiometer to adjust the output voltage. It can also be fixed to provide a specific output voltage. The way to fix the output voltage to 5V can be seen on the right photo. The copper trace of the ADJ is cut and a drop of solder is bridging the two solder pads of the 5V position.

Double turnout decoder

eltraco_to_layout.jpgOn the turnout decoder the position for the two fuses is depicted with the vertically placed resistor.


Single turnout decoder


The value of the components is now on the PCB.


Sensor decoder



Switch decoder

eltraco_sw_layout.jpgAt left the layout for the switch decoder. It depicts version 4.0a of the design. The Pcb's below are created with version 4.0 of the design. When the Pcb's arrived I realised that the Wemos module was positioned the wrong way. Hence I changed this and voila version 4.0a.

eltraco_sw_pcb5.jpgThe PCB's presented here are conform revision 4.0. The last picture shows the Wemos module in the position for revision 4.0a but on this PCB it will not work in this position. The "Gerber" files etc. provided are all version 4.0a.

Current detector

eltraco_cd_layout.jpgOne pole of the driving current(red) needs to be connected to pin 1, the right most pin, of the 5 pole connector. Pin 2 .. 5 provide driving current after detection to one and the same block. These 4 contacts provide the possibility to feed a long stretching block at four positions.


Hall sensor


DCC++ Command Station


Servo assembly


users/eporocrail/putting_hardware_together-en.txt · Last modified: 2018/11/12 08:56 (external edit)