So after seeing some discussions on relay boards and the trouble folks have with getting the various ebay modules working, I decided to develop a Mega/Due based Relay shield.
Kept it simple - Omron G5T-1A 5A SPST thru hole Relay capable of 120AC/240AC/30VDC @ 5A, 3.5mm pitch screw terminals, double 110mil wide traces for lots of current capability, with NPN BC846 transistors needing low current to turn on, 750 ohm base resistor, and 1206 diode for induced coil current handling mounted under each relay.
Board is wider than a Mega also with mounting holes that do not interfere with the Mega headers.
http://www.components.omron.com/components/web/PDFLIB.nsf/0/FE367B32CF6CFE818625739300706BB7/$file/G5T_0609.pdf
Relays are available with 5V (40mA) or 12V (16.7mA) coils.
Relay coils can be powered from onboard 5V,VIN, or 5V/12V can be brought in from external.
Any thoughts?
Figured I'd do an Uno version next with a shift register vs committing 8 pins.
I don't think I see any LEDs to indicate when the relays are picked or dropped. 8)
Got any Bobuino2s left?
I'll put together an order.
Relay shield, with relay's driven by shift register.
Clock/data/latch only go to a header, vs SPI pins, for flexibility.
LEDs to show state, I can add that.
Bobuino2 are available.
E-mail me, let me know about FTDI & screw terminals.
Bobuino2 are available.
E-mail me, let me know about FTDI & screw terminals.
Got to get ready for Xmas.
I'll put together an order in about a week.
(maybe 4-5, Bobuino2s and 4-5, 1284weenys)
Looks great.
I would try testing it by creating some code that prints to serial monitor a counter status of ON/OFF cycles, then drive all relays ON/OFF simultaneously and/or in a pattern ... perhaps even while switching an inductive load.
perhaps even while switching an inductive load
Well maybe add some SWC to the contacts then, Transorbs or MOVs, however, one should as usual look after an inductive load at the load itself.
Well maybe add some SWC to the contacts then, Transorbs or MOVs, however, one should as usual look after an inductive load at the load itself.
No, the testing wouldn't be for that purpose ... the idea would be to see if the proximity of the relays to the MCU or other electronics could cause any problems while activating ... just some pre-production stress testing.
The coils are not driven by Arduino/328P outputs directly. The NPNs and TPIC6C595 provide signal isolation.
Think I'll add a barrel jack connector in parallel with the screw terminal so users don't need to cut ends of power cables to supply coil power.
The proto area is a new symbol.
LED for relay power could be useful.
The proto area is a new symbol.
I am not familiar with Eagle.
I use WinQcad, you can hide the pin name and the pin number.
You can do similar with Eagle. I wasn't too concerned about it on the schematic as it's just a 15x20 area of unconnected holes.
I got the barrel jack squeezed onto the boards, forgot the relay coil power LED when I was adding them tho. Will add that and am then ready to order some boards.
Company credit card was caught up in the Home Depot data breach, waiting on a replacement so I can buy parts from digikey. Had a couple of UK charges show up that made it apparent something was going on - wasn't me riding the London Eye!
Got my first relay card assembled, a Mega with 8 relays, screw terminals, and relay-on LED indicators.
D22-D29 drive NPN transistors to drive the relay coils, with 5A/250VAC/30VDC SPST contacts.
First time doing double-side mounted SMDs, that was kinda of interesting.
Nice work as usual.
With SMD on both sides you do have to think a bit differently when laying things out.
It does give more real-estate for your CCTs.