Tag Archives: shield

Universal Signal Isolator Shield: Rev. 1.2

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Since there has been a lot of interest in my Isolator shield these past few months, I have been optimizing its design.

The result of this optimization is this PCB:
Rev.-1.2-pic
It’s called “the Rev. 1.2”.

Nothing major has changed. The pinouts are still the same, the major components are the same, the functionality is essentially the same.

The changes are as follows:

  • New SPI header. It just passes through the SPI signals, nothing more. It does not connect to anything on the board.
  • New SPI_CS header. Useful only if / when connecting SPI peripherals.
  • Reset button. Because you never know..
  • New circuitry for the POWER_RELAY header. It now uses a MOSFET and it includes a diode for the reverse current coming back from the relay’s coil.
  • Decoupling cap for the IR receiver. Not absolutely necessary, but good to have.
  • More decoupling for the DC_UNR input.
  • Ground planes. Lower Arduino noise, at least in theory.

Here is the updated parts placement:
USI-parts-placement-rev1.2

And this is the updated BoM:

[table “” not found /]

Soon I will update the shield’s page with the new info.

They’re here!

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I’m talking about my new Universal Signal Isolator PCBs:

USI_bare_slanted USIs_bunch

IMG_0320_res

I built one to test it out and everything seems to be working as it should. Next step is a page for the project, with schematics, a BoM and build instructions.

It is compatible with the current versions of both the ArDAM1021 and TFT HiFiDuino projects.

For now you can find more info in this post.

 

Universal Signal Isolator shield for Arduino DUE & MEGA

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A few years back I designed a little Arduino shield who’s main function was to provide electrical isolation between an Arduino and a DAC (specifically a TPA Buffalo III).

The years have passed and my needs have changed with the introduction of the dam1021 DAC and its serial interface. My first though was to design a new shield specific to the dam but then I said “why not design a universal isolator shield?”. It would provide electrical isolation for both I2C as well as serial signalling.

Thus was born the Universal Signal Isolator shield for Arduino DUE & MEGA:

v0.97_crop

OK, it does look a lot more complicated than my first shield but remember, you only need to solder in the parts that your DAC actually needs.

So, what does this thing do?

1) Electrical isolation of I2C signals, complete with support of 8 isolated inputs or outputs (via an MCP23008 IC). Three of the MCP’s pins are high current outputs (up to 100mA).

2) Electrical isolation of up to 2 serial ports (implemented with an Si8642).

3) Electrical isolation of the second I2C interface of the DUE (implemented with an ADUM1250).

4) Powered either by 5VDC, 8-15VDC (non-regulated) or 7-12VAC (includes support for on-board rectification and filtering).

5) Support of a 5VDC power relay (up to 100mA).

6) Header for connecting a Nextion display.

7) On-board EEPROM memory (24LC256).

8) And of course full compatibility with the previous shield (same pinouts for the encoders, IR, TFT, etc.).

I will release the Eagle files once I have confirmed that the shield works as expected (I’m waiting for the first (and hopefully last) batch of PCBs).

TFT Hifiduino Code v0.95

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Update: TFT Hifiduino Code v0.95 available!

Download from here: B3_arduino_code_v0_95 (Note: As always, the code on this page may not be the current one, i.e. there may be a newer version available. The latest version is always up at the project’s official page.)

Here is a partial changelog:

– Changed rotary encoder code. Should work for MEGA as well as Due (no longer using interrupts).

– Added remote control codes for virtually all of the functionality that is offered by the encoder so now all of the parameters can be set via remote.

Bugs:

– Selection bar is still buggy. Haven’t gotten around to sorting it out.

Missing functionality:

– Disply backlight handling. It is next in line to be sorted.

– Sleep mode. Much research is needed, so won’t be implemented soon.

Also, I’m working on a simple MEGA / Due shield that should simplify things a lot. It is a work in progress, so I’m not ready to publish schematics or anything, but you can have a look at the current version’s 3D model:

Render_01