Sinclair ZX80 / ZX81 / Z88 Forums

Hi,

I'm working around the DJY-40 module.
It allow to send or receive serials datas or a 8 bits GPIO bus, with a distance of 120 meters.

Data sheet: https://www.rcscomponents.kiev.ua/datas ... asheet.pdf

The config of the chip is poorly detailed and let me in a trouble.

This new original project is a first try to drive eighth miniature locomotive located in a narrow case.
It will be able to drive the speed, the way (forward and reverse), the horn and lights.
Rail will be powered with 12v AC, for all trains, and the module will drive each locomotives by RF signals throw the modules IDs.

I give you the raw project as is.

But, i can't tell you if this project is realistic, without more informations on the DJY-40 module.

I prepared the schematic for the ZX81 card. (POKE 10 to 17, 8x8 buffered outputs)
And the locomotive schematic, but need help around the PWL (NE555) pulse drived by a simple DAC circuit.

Have a look to my primary work, and let me know.

ZX81 card schematic: Locomotive driver: Have fun.

Hi,
Here the ZX81 card.
Don't suit to the SPECTRUM connector.


Schematic: NOTE: This release had to be update with a /ROMCS high level while sending data.
D0-D7 are locked and target to the BASIC ROM, not on the card.


Have fun.

Update 0.1:
D1 added to drive the /ROMCS

Schematics:
Kicad project & Gerber:

Hi,


This module is a locomotive driver based on a DJY-40 mini-circuit.
It alloy to send a serial value to another mini-circuit on a 8 bits IO BUS.
Each mini-circuit had to be set to a name ID 1 to 8 (256 available) and be set to the BUS mode.

We use 3 bits (B0-B2) for the speed. 0 to 7 voltage rang (step 2v),where 0 is STOP and 7 FULL Speed.
1 bit (B3) to set the forward or reverse mode.
1 bit (B4) to the horn (buzzer).
3 bits (B5-B7) are free for other stuff.(magnetic coupling, smoke generator, waggons lights...)

The front and rear lights are coupled to the B4 bit, and can be connected on a pinhead connector.

The remote can be use to test or move the train without the ZX81 card.
You had to push SPEED1+SPEED2+SPEED3 to reach the full speed, SPEED3 set the rang 4/7 (VCC/2)

You can use a 12v-9v AC on the tracks, the driver have a DC rectifier.

25x175mm PCB, can be place on his edge if no room in the locomotive.


The voltage divisor can be made with 1/4 W resistors, but 1/2 W will avoid to create heat inside the train.

The circuit seem to be reliable, but had to be test (poor DJY-40 datasheet).

Have fun.



Wiring diagrams:

Update 1.2:
-U4 (L7805 regulator) footprint was corrupt.


Kicad 9.0 project:
Full Kicad project (DC motor driver & remote)
Notes:
To update to Kicad 9, just update the binarys, not the libs.
Move your old one in the "/9/share/kicad" directory.
Take care to preserve your updated librarys in "symbols" and move all new files in "3Dsharpes" an "footprints".
Or install the full 9 release, and overwrite all new files, with older one.
Hope the library's problem will be solve in next release, especialy the "Symbols" path, using single-file features.
The library manager able to help, but never worked properly on my computer !


I experimented a bugg in the 3D viewer, with a "ALL BLACK" preset ! (Night mode!)
Just change colors to "DEFAULT COLOR" by clicking the color square.
Change all colors to default, and save it to "Default PCB".