Need some help with schematic

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26201

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I am getting things together for a launch controller. I read through the ground support from a search on launch controllers and came across a post by a member here on the forum. I tried contacting him and haven't had a reply as of today. I want to build a controller just like the one in the pics below so I need someone to help with a schematic. I listed the components as well per zipstrip. Also, any resistors needed? I want to add that I will be using a car battery or 12v lawn tractor battery. What wire should I use? Extension chord?
Looking forward to the feedback,
.View attachment 342664View attachment 342665

Radio Shack – (1) Green LED with Holder Item#: 2760271 (2.19)

Radio Shack – (1) Orange LED with Holder Item#: 2760272 (2.19)

RadioShack – (1) Red LED with Holder Item#: 2760270 (2.19)

Radio Shack – (1) PK2 PHONE PLUGS Item#: 2741536 (4.19)

Radio Shack – (1) 76dB Piezo Buzzer Item#: 2730059 (3.59)

Radio Shack – (1) Panel-Mount Jack Item#: 2740252 (4.79)

Radio Shack – (1) Project Enclosure (6x4x2") Item# 2701806 (6.49)

Amazon – (1) Gardner Bender GSW-22 Normal Off Push Button Switch (4.83)

Amazon – (5) Schumacher EC-25 25' Cable Connector Extension Cord (39.95)

Amazon (by Pinkcoo) - Red LED Aircraft Type Carbon Fiber SPST Toggle illuminated (2.99)

Amazon (by Pinkcoo) - Green LED Aircraft Type Carbon Fiber SPST Toggle illuminated (2.99)

Hobby Lobby - Avery Clear Sticker Paper (3.50 w/ coupon)

MISCELLANEOUS

(3) ¼ Washers – super custom painted black (pennies)

(2) Romantically involved ¼ Quick Disconnects (pennies)
 
Where are you in Ohio? One of our club members built a wireless multi-pad system so I know he could provide assistance with the electronics. Our club meets every Tuesday from 6 to 8:30PM at eRockets in Dayton. You are welcome to attend. You do NOT need to join the club.

We have a launch scheduled for Saturday, April 14th near Cedarville, but the weather does not look good (wind and rain). Check out our website at WSR703.org for more info about our launches and our weekly meeting.
 
Anyone with experience on this? Gotta be someone willing to help me?

Thanks
 
As far as I can tell the circuit is something like this- (ignore the dots- the forum deletes extra spaces, so they're just placeholders)

_________Power LED_Resistor_____________________________________
| . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
|___Key____Continuity LED_Resistor_________Switch 1_____Igniter 1____|
| . . . . . . . |____Launch Button_____| . . |___Switch 2______Igniter 2____|
| . . . . . . . | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
| . . . . . . . |______Bypass LED__Resistor____________________________|
| . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
|_____________________Battery__________________________________|

I have a very similar, though less fancy, controller, and I used household hardware and normal outdoor extension cords. Any heavy gauge wire should work, though, as long as you have enough of it.
 
LithosphereRocketry said:
As far as I can tell the circuit is something like this- (ignore the dots- the forum deletes extra spaces, so they're just placeholders
Click to expand...

It doesn't have two outputs. A power switch, removable safety interconnect, arm switch, and launch switch. Which is two switches too many.

The two hooded toggle switches are just eye candy. (power and safe/arm)

Something this simple, even with the complicating and redundant features, doesn't really need a schematic.

As for resistors, that depends on what you find to replace those Rat Shack LEDs. Get something with an LED built in and you don't need one. Otherwise start with 1K series resistors and adjust up if the LED is too bright.

The listed cable is puzzling. It is too short for anything bigger than 30N-s. If that is all you are launching, an Estes launch controller is more than adequate. A 50' extension cord would be a cheaper and better alternative.

simple.png
 
UhClem said:
It doesn't have two outputs. A power switch, removable safety interconnect, arm switch, and launch switch. Which is two switches too many.

The two hooded toggle switches are just eye candy. (power and safe/arm)

Something this simple, even with the complicating and redundant features, doesn't really need a schematic.

As for resistors, that depends on what you find to replace those Rat Shack LEDs. Get something with an LED built in and you don't need one. Otherwise start with 1K series resistors and adjust up if the LED is too bright.

The listed cable is puzzling. It is too short for anything bigger than 30N-s. If that is all you are launching, an Estes launch controller is more than adequate. A 50' extension cord would be a cheaper and better alternative.
Click to expand...
Care to share a setup you would recommend? Drawing?
 
LithosphereRocketry said:
As far as I can tell the circuit is something like this- (ignore the dots- the forum deletes extra spaces, so they're just placeholders)

_________Power LED_Resistor_____________________________________
| . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
|___Key____Continuity LED_Resistor_________Switch 1_____Igniter 1____|
| . . . . . . . |____Launch Button_____| . . |___Switch 2______Igniter 2____|
| . . . . . . . | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
| . . . . . . . |______Bypass LED__Resistor____________________________|
| . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
|_____________________Battery__________________________________|

I have a very similar, though less fancy, controller, and I used household hardware and normal outdoor extension cords. Any heavy gauge wire should work, though, as long as you have enough of it.
Click to expand...
Having a bit of difficulty understanding this. Can you simplify?
 
26201 said:
Having a bit of difficulty understanding this. Can you simplify?
Click to expand...

UhClem's drawing is much better- just go with that. The only component that isn't accounted for is the power LED & switch in the original box- just a switch on one battery terminal and an LED & resistor between the switch and other terminal.

For mine, I used a plain 5mm yellow LED with a 330ohm resistor. A 5mm LED can take about 30mA, so just take the input voltage, subtract 2V (weird LED voltage drop), and divide by 0.03 to get the minimum resistance- that's all derived from V = IR (voltage = current * resistance). Other LEDs may be able to take more abuse, but my cheap 5mm is easily visible in direct sunlight, and they're literally pennies apiece.
 
The only component that isn't accounted for is the power LED & switch in the original box- just a switch on one battery terminal and an LED & resistor between the switch and other terminal.

What? Not clear?
 
26201 said:
The only component that isn't accounted for is the power LED & switch in the original box- just a switch on one battery terminal and an LED & resistor between the switch and other terminal.

What? Not clear?
Click to expand...

Sorry... here's a schematic:
controller.JPG
Does that make some amount of sense?

What this should do, assuming each step includes the steps before it, is:
Turn on power- POW lights
Insert key/turn on switch- ARM lights
Connect igniter- CONTINUITY lights
Press button- Igniter fires
 
Unless the battery is inside the box, the power switch and light is wasted effort. If you want to turn it off, just disconnect the battery clips.
 
UhClem said:
Unless the battery is inside the box, the power switch and light is wasted effort. If you want to turn it off, just disconnect the battery clips.
Click to expand...
I only included it because it was in the original front panel design- I agree that it's not necessary. My box has a built-in battery but no power switch- there's zero "phantom load", so the controller is just always on.
 
Thank you guys for the effort, I appreciate your time! I don't see the plug key in the schematic. After studying the schematic your right, pointless for a power switch and led.
 
It's represented by "interlock" in my diagram and S1 in UhClem's. If you want two interlocks/keys, you can connect them end-to-end in the place of the switch.
 
You guys talking something like this? Me like this. So on the schematic I would omit the on/off switch and the led that corresponds with it?
Would you be willing to update the schematic?
 
If you want to have a removable safety interlock, it's essentially the power switch... move it from where it is to where your power switch was in your original schematic. It better be able to handle the current, though... I'd use at least a 1/4" phone plug, and you might want to think about using banana plugs instead.
 
Question on the resistors. What watt do I need? Also why the substantial difference in the schematics in ohms?
 
26201 said:
Also why the substantial difference in the schematics in ohms?
Click to expand...

Assumptions.

I assume that you want to limit continuity test current to no more than 10mA. With typical LED forward voltages and a 12V battery, 1K is about right.

Also, LED efficiency varies widely. It used to be that you had to drive them at their maximum current (~20mA) for them to be visible in daylight. You can now get LEDs with high enough efficiencies so at that drive current they would be too bright to look at.

Get an efficient LED (> 1000mcd) and use greater resistance to limit current as needed.

Resistor size is easy. Just assume that it drops the full 12V. Then power is (12V^2)/R and you want a resistor with plenty of margin so use resistors rated about twice that. For example, a 1K resistor would be running at about 0.144W so a 1/4W part would be fine. Particularly when you consider that operation is intermittent and not continuous.
 

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