Help needed for 5 button selector circuit

yes, with that kind of switch you can do it. on each switch you need to use the NC (normally close) contact on one side to maintain a constant voltage to all relays on one of the NO (normally open contact). So each Relay needs to be a DP, one pole for your use and the other for the Loop lock to keep the relay in. All the switches will be wired in series using this NC contact so that when ever you press one, it will open the circuit at the end of the string which is supplying the lock voltage on the contacts.

So just picture the lock voltage being connected to each (NO) contact of each relay in parallel. on the other side of the (NO) of each relay, you will connect one side of it's own coil. This is where Coil will be getting it's energized voltage from to hold it on. the other Coil connection will just be tied to common along with the rest of the relays. -- Now for the activation of the relay you want --

When you press a button, the (NC) contacts on the switch that is in series with the rest of the (NC) contacts of the other switches will open. this will cause loss of voltage in the remaining string of (NC) contacts and which ever relay that was locked on will now release. With the (NO) normally open contact of each switch, you will supply to each coil power on the coil side connection of the relay.. remember i said the coil will be connected to the opposite side of the locking contacts on each relay? this is where you connect your momentary source to pull in the relay. when the relay pulls in, the locking contacts will maintain it and with the mechanical slowness of the relay returning, you should be able to release the button quick enough to have it put the locking source back on before the relay pulls open. If you find that the relay pulls back to soon? You can then use a Cap on the output of each switch that energizes the relay coil going to common to hold a charge. use a diode in series after that to feed the relay coil. The diode is to prevent the cap from being charged while the relay is locked on so that it releases quickly, and only be charged from the switch.. I don't have a ASCII translation program to use here otherwise, i would have drawn it out for you.

personally, i would use Flip Flops with RESET and SET (RS) type. The (NC) would force a Reset of all flip-flops with their RESETS tied together, and the closer and opening of the NO contacts would be tied to each Flip-flop's SET pin. The Q outputs would reflect the state. The RESET and SET pins need to be pull low to high to activate. you would need small cap on the reset line to prevent debouncing.

--
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

Hi, Glenn. You want simple? Here's simple. Get a 12VDC supply, some

5VDC coil DPDT relays, and 5 resistors R that have a resistance about 1.2 times the coil resistance of the relays, and can handle the wattage when 12VDC is applied. Go to your junkbox and dig up 25 diodes, and make 5 of these (view in fixed font or M$ Notepad):

| VCC | + | | | .-. | R1| | | | | | '-' | | | o--< From SW2 | | | o--< From SW3 | | | o--< From SW4 | | | o--< From SW5 | | | .----o | D| RY1| | - C| D | ^ C| .--|

Thanks! Both of those are great ideas! I was trying to think digital but good old hard wiring works.

-- Glenn Ashmore

I'm build>> I have a bank of 5 DPDT momentary push button switches like the kind used

This will do it, and you can use simple SPST momentary pushbuttons.

PNP +12 -+--. .------[1K]----+----+----+----+---{{{-+----+ | e\\ /c | | | | | | | --- [D6][RLY] [D7][RLY] [D10][RLY] | | |a | |a | |a | | | +----+ +----+ +----+ | | | | | | | [SCR1] [SCR2] [SCR5] | | Pb1 /| /| /| | | ___ | | | | | | `----------+--o o---[10K]--+ +---------+---{{{------+--+ | | | | | | | | +--->|-------+ | | | | | D1 | | | | | | Pb2 | | | | | | ___ | | | | | +--o o---[10K]------------+ | | | | | | | | | | +--->|-------+ | | | | D2 | | | | {{{ {{{ | | | | Pb5 | | | | | ___ | | | | +--o o---[10K]------------------{{{----+ | \\ / | | | D11 --- +--->|-------+ | | D5 | | | | | `------+---[.1uF]------+ | | | | [1K] [10K] | | | | Gnd --------------+---------------+-------------------------+

For SCRs you can use 511-X00602MA2AL2 from Mouser, (18 cents each) or anything else that will turn on at relatively low current, with a hold current of ~ 10 mA. Diodes are 1N4148 or whatever you have, and the PNP can be just about any common jelly bean part, like a 2N3906.

_How it works_ The PNP is biased on by the 1K and D11, until a + pulse through the .1 uF cap biases it off, briefly. That causes any SCR that is on to turn off. The + pulse occurs when any button is pressed. Whichever button is pressed gates the corresponding SCR on, which energizes the corresponding relay. The SCR stays on until the next time a button is pressed.

Ed

one set of NC switch contacts is used to cut the holding power of the other relays

shown is relay m of n

___ ___ | | _-v .--->ONm +V --o | o...o | o--->>-----~: | --- --+-- --+-- Vsus : ^---+-->|-.D2 | S1a Sna : | --+-- |~|---+------+-------o o---< +V |\\| `-|