Posted: 8/20/2015 10:08:29 PM EDT
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I am trying to have one buzzer for two or more switched circuits. All wires are grounds except the red line which is hot all of the time. I would like each circuit to ring the buzzer. It does that. Right now, triggering either momentary switch will light both of the warning-LEDs. I want to light ONLY the warning-LED related to the circuit that is closed. Is there a way to do this?
If it were the power being switched, I could use a diode, but I'm not familiar with a diode that would work in this situation. This is for a survival related project, if that makes any difference. General Discussion moves so fast that the electronics gurus won't see it. Thanks very much for your input. 
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You need to rewire this.
The reason why it does not work the way you want it to is because the switches are not controlling the power. You have the switches switching the ground instead of the power Take the plus of the battery and go to one side of each switch only. Take the other side of the switch and go to the plus side of each LED for that side and the buzzer. then connect the other side of the LEDs and the buzzer to ground, ie the negative side of the battery. That way when one switch is pushed you only send power to one side of the LEDs and the buzzer. Not sure what the toggle switches on the bottom are supposed to do. |
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You need to rewire this. The reason why it does not work the way you want it to is because the switches are not controlling the power. You have the switches switching the ground instead of the power Take the plus of the battery and go to one side of each switch only. Take the other side of the switch and go to the plus side of each LED for that side and the buzzer. then connect the other side of the LEDs and the buzzer to ground, ie the negative side of the battery. That way when one switch is pushed you only send power to one side of the LEDs and the buzzer. Not sure what the toggle switches on the bottom are supposed to do. The toggle switches arm the system (to the left) or test the buzzer and light when pushed to the right. The momentary switches are pressure switches used to set off the alarm when the toggle is set to "ARM". |
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You need to rewire this. The reason why it does not work the way you want it to is because the switches are not controlling the power. You have the switches switching the ground instead of the power Take the plus of the battery and go to one side of each switch only. Take the other side of the switch and go to the plus side of each LED for that side and the buzzer. then connect the other side of the LEDs and the buzzer to ground, ie the negative side of the battery. That way when one switch is pushed you only send power to one side of the LEDs and the buzzer. Not sure what the toggle switches on the bottom are supposed to do. I'm going to ASSUME that the toggle switches are supposed to control which led is supposed to illuminate from the switch. As I see it (and correct me if I'm wrong) the toggle switch on the left side should determine which led on the left of the circuit the left momentary switch connects to and the same fore the right side respectively. Did I get that correct OP? EDIT: You guys respond with lightening speed! |
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don't know why the pic is sideways.
anyway. left side power goes to the center toggle. In test the left Red LED and the buzzer both go on. in arm, the power goes up to the momentary switch,and also powers the amber LED, when the switch is pressed, the power goes to the buzzer and is prevented from going to the right red LED by the diode. it also goes to the left red LED. Same thing happens on the right side. is that what you are looking for. the half circle around a wire means the wires are not connected. the negative side of the battery symbol is ground. Everything like that is connected. One side of the LEDs and buzzer. |
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Ok, OP has his answer, now.... THE PRICE!
Don't worry, were cheap. Diodes act like a one way valve, with current flowing only in the direction of the arrow on its schematic symbol (from anode to cathode, or "its plus side to its minus side"). OP, think about it a little and tell us WHY this works? No points off for a wrong answer, but we'll be teaching you how to fish instead of just handing you a makerel. :). If your answer is off, we'll give you more guidance. :) |
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How do I select the proper diode? The buzzer uses 20mA. There are thousands of diodes on Mouser. Thanks. Quoted:
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when you use the diode, the current flows from the end without the bar to the end with the bar. and is blocked going the other way. How do I select the proper diode? The buzzer uses 20mA. There are thousands of diodes on Mouser. Thanks. There should be a table that shows the specs. Double the current of all your LEDs and the buzzer, use that figure the minimum for diode current. No need to crazy past that much. Max fwd voltage should be in excess of your supply, I'd go with a factor of 2. |
| I was just catching up on this thread and there is an interesting feature of the revised design that perhaps has gone unrecognized: when the Test/Set switch (why not "Test/Arm"?) is in the Test position, if there is an alarm condition (momentary switch closed) or a short circuit of the alarm wiring, the Ready indicator will illuminate. Not sure that's worth anything, but it will work that way. |
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...guess you didn't get the memo. It's dead, Jim. Quoted:
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Just go see what radio shack sells and buy two. ...guess you didn't get the memo. It's dead, Jim. Rumors of my demise are greatly exaggerated [RS] Radio Shack has many open stores, their franchisees are still around. |
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Rumors of my demise are greatly exaggerated [RS] Radio Shack has many open stores, their franchisees are still around. Quoted:
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Just go see what radio shack sells and buy two. ...guess you didn't get the memo. It's dead, Jim. Rumors of my demise are greatly exaggerated [RS] Radio Shack has many open stores, their franchisees are still around. yep. they closed a bunch of stores, not all of them. |
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I was just catching up on this thread and there is an interesting feature of the revised design that perhaps has gone unrecognized: when the Test/Set switch (why not "Test/Arm"?) is in the Test position, if there is an alarm condition (momentary switch closed) or a short circuit of the alarm wiring, the Ready indicator will illuminate. Not sure that's worth anything, but it will work that way. True, if you put the toggle in test and press the SPST the amber LED will also illuminate. We don't know what the SPST switches actually are. If they are momentary, since there is no latch, the red LED and buzzer may never go on. If they are throw switches, then they will. OP never said what the application is. I am assuming the test function is just to make sure the battery, Red LEDs and buzzer work before arming the circuit. When you arm the circuit, the amber LED goes on so no need to test that, That is obvious, but he never said what the application is. |
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True, if you put the toggle in test and press the SPST the amber LED will also illuminate. We don't know what the SPST switches actually are. If they are momentary, since there is no latch, the red LED and buzzer may never go on. If they are throw switches, then they will. OP never said what the application is. I am assuming the test function is just to make sure the battery, Red LEDs and buzzer work before arming the circuit. When you arm the circuit, the amber LED goes on so no need to test that, That is obvious, but he never said what the application is. Quoted:
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I was just catching up on this thread and there is an interesting feature of the revised design that perhaps has gone unrecognized: when the Test/Set switch (why not "Test/Arm"?) is in the Test position, if there is an alarm condition (momentary switch closed) or a short circuit of the alarm wiring, the Ready indicator will illuminate. Not sure that's worth anything, but it will work that way. True, if you put the toggle in test and press the SPST the amber LED will also illuminate. We don't know what the SPST switches actually are. If they are momentary, since there is no latch, the red LED and buzzer may never go on. If they are throw switches, then they will. OP never said what the application is. I am assuming the test function is just to make sure the battery, Red LEDs and buzzer work before arming the circuit. When you arm the circuit, the amber LED goes on so no need to test that, That is obvious, but he never said what the application is. Sorry I didn't see the new replies until just now. The new text is TEST/ARM. The pressure switches will not reset. If they are tripped, the connection stays closed until the device is manually reset. While I have you electronic gurus, may I ask another question? I'm working on a wireless version of this same setup. After some initial research, it looks like I can't send a simple ON/OFF signal (from the pressure switch) by wireless to the buzzer setup without converting the signal to a digital language with coding for the wireless card to transmit. I think I need something like this, but with some type of card like an Arduino to create the code at the alarm pressure switch and another in the monitor-box to decode the signal. Is this correct?. wireless Any thoughts? |
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You can use something like this without having to fool with parsing digital data. However it will not be as reliable as a hardwired connection.
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You can use something like this without having to fool with parsing digital data. However it will not be as reliable as a hardwired connection. Yea, that worries me. It seems like the 433 Mhz frequency has problems with interference. So much to learn, and a limited number of hours in one day. |