Electronics > Projects, Designs, and Technical Stuff

Tiled control panel ideas

<< < (3/4) > >>

Ian.M:
Use RS-485.  The hardware is cheaper than CAN, and resource requirements on the MCUs are low, though I would get ones with a hardware UART.   Snaking a ribbon cable  to and fro behind all the tiles with an IDC socket on a header for each board would be the easy way to hook them all up.   Each would need a unique address  but that would be easy enough to do when the MCUs are programmed or one board at a time in a test jig with a normally grounded pin on the header pulled high to put the board into address learning mode. 

If you want inspiration for a protocol to run over RS-485, consider MODBUS RTU.

USB<=>RS-485 interfaces are readily available so you can do most of your testing and commissioning from a terminal program running on your PC, without suffering from having to get both the master and slave device firmware working properly without knowing which end the problem is.

Marco:

--- Quote from: Doctorandus_P on February 16, 2019, 04:21:51 pm ---With Uarts you can also easily use a diode on each device and connect RxD and TxD together to make a wired-or (wired-and, nand, whatever) bus. Bus capacitance may become a problem, you can consider using a strong pullup (100 Ohm or less) and a NPN transistor on the TxD line of each uC.

--- End quote ---

In this case 1-wire is an option. Might have to tweak the protocol to allow a new slave to indicate its presence to start a new enumeration cycle.

T3sl4co1l:
Keep in mind EMC -- if you want this thing to behave while in any sort of noisy environment.  Don't underestimate how noisy a mere finger is -- especially in dry weather!

Consider not using logic level and open collector buses.  This rules out I2C, stock SPI, async serial (logic level), and so on.  There are I2C-RS422 converters, but really you'll have an easier time with SPI or shift register chain (74HC164s and 595s) plus RS422 transceivers.  CAN is a combo RS485-like interface plus protocol, very reliable for these sorts of things.

Or shove everything behind a shield as well as you can, or provide frequent grounds so each tile can be individually grounded and protected and filtered.

It doesn't seem like you'd get very much value out of a single tile that size (unless it's covered in LEDs..?); you may consider a hierarchical approach, where the smallest tile elements are dumb, and several can be wired into a common interface which has probably an MCU and comms.

Tim

Doctorandus_P:
How far are you with your tile project?
Have you considered using 32mmx32mm tiles?
This is the size of very common 8x8 dot matrix displays with MAX7219.

Smaller PCB's wil also make the individual PCB's cheaper.
Or allow you to put more (diffeent) tiles in the same area.

danners430:
Hey guys, sorry for the radio silence - I never got notifications unfortunately when I got replies...

(For clarity - Tapatalk is just the app I use on my phone to access the forum... And I'm using the free version, hence the adverts)

Bit of an update:

I've purchased a whole bunch of HT1632C LED matrix drivers, which were cheap as chips, so I'm just gonna connect all the LEDs in a matrix with a wiring harness - basically keeping it simple, albeit with a little more wiring to do.

The 40x40 PCBs are dictated by the tiles on the control panel itself, which is already manufactured... I've been given the thankless job of kitting it out. Should be simple though using the matrix controllers, the PCBs are essentially now just a mounting solution for the LEDs...

Many thanks for all your suggestions, and my apologies for the silence

Sent from my ONEPLUS A3003 using Tapatalk

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod