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gca-wiodrive-en

WIODrive Central DCC station, booster or Motor controller.


Copyright Rob Versluis and Peter Giling


Description

WIODrive was first developed as a booster (WIOBoost), but quickly the idea changed to make it a central station.
And developing that, the idea emerged to also be able to simple control a motor speed.
And the H-bridge chip L6203 on this unit provides all these options with a max of 3,5 Amp.
Now, by simply making the right settings, WIODrive will behave as described:

  • Central station (display connection also available)
  • Booster with its own current limit switch.
  • PWM motor speed control.

This last option makes it useful to remote control motorspeed, when build in in a G-scale loc or tender.

The complete WIODrive is basically not more that an ESP8266 D1 module, a power driver L6203 and a voltage regulator.
The large resistor at the top left corner is the 0,47Ohm resistior where the current is measured.
The standard A/d converter in the ESP is not really accurate, but perfectly suitable for this.

Power supply

Connection to connec tor marked PWR1.
Power supply needs to be adapted to the right scale, when used as booster or central station.
There are a few levels that should be considered.
N scale needs 12 - 16 Volt
HO scale needs 15 to 20 Volt
G and 1 need 19 to 24 Volt
It is advisable to select the right voltage for the WIODrive.
So in short time, a small power supply will be available to give you that selection.
It is deliberately not included on the WIODrive, to keep the unit as small as possible.
This unit, with a groundplane of only 56 x 50 mm, contains only through hole mount parts, without any SMD.
That fact ensures the possibility of an available kit.


Central station

When WIODrive is set for DCC, it will provide the loc commands to the rails, with a maximum current of approx 3 Amps.

Booster

In fact the same function as central station, but the pulses com in from another WIODrive.
Booster will switch on its rail output, when a decent DCC signal is received.

Motor drive

The pulse output from D32 can also be set as PWM, which will control the speed of a connected motor.\

Short circuit protection

Th L6203 is provided with its own hi current and hi temperature protection.
But in practice there is a better ways to do that.
Specially the reaction to a short circuit on the rails should cause a fast reaction.
The booster itself (like the central station), will shut off when the max amps is reached.
This maximum can be changed in Rocrail settings.
After shut off, the WIODRive will wait approx 5 seconds, and after that will try to start up again.
In this short circuit situation, the pulses from the central station remain available, even when the
central station itself found short circuit.
The H-bridge is controlled that way by the enable input, without effecting eventually connected following WIODrive boosters.

Multiple boosters

Tne IBB connector of the WIODrive is available for connection a following -as Booster set- WIODrive.
Railsections, connected to different boosters, should be separated with al least on rail cut of the two.
The short time that a train is getting power from two boosters, is no problem at all.
Even the cutout for Railcom is 100% in phase, between boosters.

Connections

Se1 servo motor

This is the 3 pin header at the edge of the board.
Please remark the or(orange) and br(brown indication, pointing to the wire colours af a servo.

ESC1

A connector that can be used for controlling an ESC motor drive, as used in remote control cars, boats and planes.
It can also be used for a second servo motor.
Important note: Please check the power consumption of the connected unit, It might be much more then the max available 0,5 Amp from WIODrive.

Hall1

To connect a hall sensor, mounted somewhere in a loc, to count the rotations of an axe.
Might be used in future for feed=back in motor speed control.
Not available yet.

IBB1

Inter Booster Bus.
To connect the next booster .
Important note: All WIODrive units, that are interconnected via this way, should have their own power supply!

RC1

A standard serial bus connection, same as om GCA_PI01.
So far, used to connect an ID-12 RFID sensor.
Further applications might be developed.

IIC1

The standard I2C connector.
This bus is very large in options, so far now, only used to connect a display.
The supply the display is set to 3.3V.

Lights

When used as a Locdecoder (motor driver) in a large scale train, these outputs provide
power for front and back lights.
They will be changed with direction of the loc.
Connection are common anode, like in all standard locdecoders.
The on board resistors R6 and R7 allow the direct connection of leds.
For your convenience, it is possible to use different values for these resistors,
so the brightness can be adapted to your needs.
Maximum output is 0,5 Amp, but with the used 2.2 kOhm resistors the current out will be max 10 mAmp

OUT1

Th obvious connector, where the rails should be connected.

Hardware

Assembling remarks

Put all parts in same order as on parts list, including the headers for LOlinD1.
Do not put in Lolin D1, it has to be programmed first anyway
Be sure to fasten VR1 with 3 mm bolt, an addional 3mm washer should be placed between board and VR1,
to avoid shortcicuit with the pads of GR1.
After soldering U2, insert GR1 at such height, that mounting holes of U2 and GR1 are in line.
This makes it possible to fix the complete unit with a bolt through U2.
PWR1 is to be connected to power supply. After switching on power supply, check voltage on 5V & GND pins of U1 (pins closest to T2).
If this unit is supposed to function as booster, do this configuration without IBB1 connected.

gca-wiodrive-en.txt · Last modified: 2020/01/20 20:59 by phg