Anyone making Kaylee’s (12 volt powered imp’s with an isolated RS485 output) as I have need of a handful of them (or something like them)
I could potentially make a Kaylee shield that you could plug P3V3 into. Looks like a pretty simple board as long as all the parts are available.
Might be worth making a very ruggedized version for potential tour use. Thoughts?
If by tour, you mean for DMX use, then you may need to add an AND gate between the imp and driver to accurately provide right length of break it uses to indicate the start/end of the stream of values.
There was a discussion before about it between Hugo and a guy using a 'scope but a search on the forum fails to find it.
If you were to do one that could do DMX, I would suggest making it easy to add buttons to (and though I have a few ideas for DMX this is not the initial thing I need it for)
I would also suggest mounting the driver in a holder (rather than soldering it down) as they can be seen as a “sacrificial” component (like a fuse) and therefore need to be replaceable
I’ll order the components and prototype… what is your time frame?
Theres no rush, what would be the minimum order quantity?
Has anyone seen that DMX thread, it had some example code and an interesting disscussion
@philmy That’s the bunny, thanks!
It’s funny the forum search box can’t find the term “DMX”
That should be a simple enough board that I could build a small quantity, and then if there was a lot of interest I would do a larger run.
Ive got a “Kaylee shield” built in Eagle that you can plug P3V3 into. Are you interested in that configuration? Is either the XLR or RJ11 jack ok?
When you say driver, do you mean the RS485 chip? Are they easily damaged? This board won’t be particularly expensive, its just the chip, and LDO and some resistors and capacitors. The XLR connector will probably be the most expensive part aside from P3V3.
I would say RJ11, the reasons being
- it would encourage someone making a cased DMX device to have the final connector mechanically separate from the pcb (so the force of a ham-fisted use of a xlr doesn’t get transferred to the circuit board)
- you side-step the tiresome 3-pin versus 5-pin dmx debate
- you bring the cost down.
The reason I mention having a changeable rs485 chips is the ones in the system I used to support regularly got toasted by installation contractors mis-wiring them.
If you not using a terminal-strip (as we were) maybe it won’t be a problem and if worse comes to worse if the board is a low-cost item the entire thing could be replaced.
Kaylee is laid out with an RJ11 connector, and then a 4 pin header. RS485 doesn’t specify any connector types, but DMX512 does. Perhaps I should use RJ45 connectors.
I would imagine we could slide a simple reverse polarity protection onto the board so that you couldn’t destroy the driver.
The RJ12 my old system used was
If you are going to go RJ45, I’d follow the DMX standard but with the addition of the +12 on both of the unused pins (to minimise voltdrop)
CAT5 Color Code
ESTA Standard Signal
White/Orange DMX Data +
DMX Data -
Alternate Data +
Pin 4 Blue
Pin 5 White/Blue
Alternate Data -
Pin 8 Brown
RJ45 seems like a good choice. Does anyone from EI know if there has been any progress made that would eliminate the need for the AND gate?
@MakeDeck I’m looking at de-glitching reconfiguration between UARTs and DIGITAL_OUTs right now, and uart.break() is also near the top of the feature backlog, but it may still be a while before either of these get released.
No worries… I’ve got an RS485 shield created in Eagle, so I’m going to get 10 boards printed and built and see how much interest there is.
I would be up for some RS485 any chance of screw terminals a well? This is a very common way to surfaces RS485 especially industrial context like talking to power meters and PLCs on modbus. A quick google RS485 images will give plenty of examples.
If I place a row of 0.1" header holes, you could install 0.1" pitch screw terminals easily… that’s no problem.
Good news thanks
In fact, I think I’ll make all the connectors easy through hole parts for the first time around… then you can populate with whatever you like, and the board will be really inexpensive.