Wireless Transmitter

[jdgriffin]

My shop is equipped with a dust collection system that is turned on-off by remote wireless (RF) transmitters.
I would love to incorporate a transmitter into my CNC mill that could be activated by an M code.
I've searched the archives with no success. I'm wondering if someone has incorporated something similar into their design. Any direction would be appreciated.

[LaserImage]

I'm not an electronics guy so don't ask me how to wire this up, but what about using a relay to trigger the switch on the remote?

Gary

[jdgriffin]

Gary -

I've thought about doing that, but it appears to be more involved than I had anticipated. The remote has two switches (one on/one off), and they are part of the circuitry soldered to the BSB.

[bharbour]

Originally Posted by jdgriffin Gary - I've thought about doing that, but it appears to be more involved than I had anticipated. The remote has two switches (one on/one off), and they are part of the circuitry soldered to the BSB.

If you have a breakout board (BOB) with a spare SPDT relay, here is a verbal sketch of a way to drive the two buttons from that one relay:
Tie the Normally Closed contact of the relay on the BOB to ground. Tie the Normally Open contact to +V (5 or 12 volts).
Connect the Common pin of the relay to the + end of a 1000uf electrolytic capacitor.

Get a pair of ordinary diodes (1N4004 or similar).
Connect the anode of one diode and the cathode of the other diode to the capacitor - lead.
Get a pair of the little reed relays. If you used a 5V power supply, get 5V relays or if you used a 12V supply, get 12V relays. Connect one end of the coil of each relay to the other ends of the diodes. Connect the other end of the reed relay coils to ground. Connect one reed relay contact pair across the on button and the other relay contact pair across the off button of your remote. Note that some of those reed relays have diodes built in, avoid that variety.

The way that this circuit works is that switching on the relay on the BOB applies +voltage to the capacitor and charges it up through a reed relay coil. The reed relay that switches on will be the one that has the diode anode connected to the capacitor. The other diode will block and it's relay stays off. The capacitor will charge up, current will stop flowing and the first relay will switch off. When you turn off the relay on the BOB, the + end of the capacitor is now grounded and the - end will be below ground. The diode with the cathode on the capacitor will now conduct and turn on that relay until the capacitor discharges. This may take a little fooling with, but should work OK. To get the reed relays to stay on longer, increase the capacitor size.

Sorry for the verbal description instead of a sketch, I am not in a place I can scan a sketch in.

Bob

[jdgriffin]

Bob -

Thanks for the reply. That sounds like a great solution.
I like the idea of only needing one pin.
Thanks again for taking the time to reply.