Plans for animation timer circuit
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Rich883
Joined: Oct 5, 2009
Topics: 17 Replies: 24
Topics: 17
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Here is the schematic for the circuit I used. There are a bunch of 555 timer web sites with calculators to change the R and C values for different timing, and for other applications so you can experiment. All the parts are available at Radio Shack, however they will be less expensive from someplace like Digikey, or All Electronics. I soldered this together on a small perf board, and use single solid 24awg wire to make the connections.
Here is a quick hand drawn schematic.( I left my laptop with Visio at work tonight.)
The power source is 12VDC
The relay is a SPDT 12VDC relay
555 Timer Pin Connections
1- Ground
2- connect to one side of the ?start? momentary switch and to a 10k ohm pull up resistor which is connected 12vdc (the other side of the momentary ?start? switch is connected to ground.
3- Connect to one side of the relay coil - This pin goes ?high? and provides 12vdc when the circuit is active (the run cycle) - the other side of the relay should be connected to ground.
4- 12vdc
5- connect one end to a .01microfarad capacitor, and the other end to ground - this would be a small disc type capacitor
6- This pin has three connections, (1)a jumper to pin 7, (2)connect to one end of a 1M ohm (1000k) resistor who?s other end connects to the 12vdc, and (3) connect to one end of a 100microfarad capacitor who?s other end connects to ground(this is a electrolytic capacitor, remember the - sign?s lead goes to the ground side) Note - this combination of Resistor and Capacitor (R/C) provides the timing for the ?Run Cycle? changing these values will change the time the relay will be closed.
7- Jumper to pin 6
8- 12vdc
In my case the momentary start switch is paralleled to both the switch in the fascia board on the layout, and a DCS Accessory(ACC) position for activation from either.
Good luck!
Rich
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JohnBoy
Joined: May 14, 2008
Topics: 110 Replies: 517
Topics: 110
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Excellent Rich, and thanks very much for the in-depth explanation on this. I've had difficulties in the past wiring up a 555 in "one-shot" mode like this, so I plan to come back to this and learn from what you've done here.
Here's the tutorial I used when I was first experimenting with 555's:
http://www.sentex.net/~mec1995/gadgets/555/555.html
Cheers,
John
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Rich883
Joined: Oct 5, 2009
Topics: 17 Replies: 24
Topics: 17
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I should note that although I typically don't, many like to place a diode across the relay to protect the chip from any spikes.
Progress: