i put the positive lead towards the timer, and here's what happened-

If I touched the front resistor lead (which would be the one going to the transbrake relay in my diagram) to ground it held time. If I held that lead to ground, it held time then turned off, even though it was still grounded. If I touched the lead to power, it did nothing.

If i left that lead and disconnected power, the LED lit for time, then turned off when the cap was depleted.

I'm going to try flipping the capacitor to have negative facing timer.

 

nothing changed.

Here's what I'm getting right now.

idle:
discharge & threshold: 0.18
control: NC
reset: 11.25
output: 0.06
trigger: 11.14

connecting input lead to ground (light comes on at first contact)
discharge & threshold: fast increase (meter only shows 6-7 volts)
control: NC
reset: 11.21
output: 11.21
trigger: 8 volts (holding lead, LED on and off)

 

This is how I envisioned the operation of the circuit.

Start with "input point" disconnected. Output LOW
(Transbrake ON)

Connect "input point" to ground. Timer cycles. Output HI Then LOW
(Launch, Transbrake OFF)

Wait (Output still LOW)
(Pass being made, restage)

Disconnect "input from ground". Output still LOW
(Transbrake ON)

Connect "input point" to ground. Timer cycles Output HI then LOW
(Launch, Transbrake OFF)

REPEAT this until you are out of money .

Also:
If that cap is .1 uF and "disc shaped" it probably
is not polarized.

 

i've been doing this with a .01 electlyte cap, and just put in a 15000f (.015uF) green square cap, no difference. It's like the edge-trigger doesn't even exist.

 

This is how I envisioned the operation of the circuit.
See attachment.

If that cap is .1 uF and "disc shaped" it probably
is not polarized.

attachment?

 

Here's how it SHOULD work:

1. The transbrake is held as the tree comes down- can be anywhere from 1.08 to 3.5 seconds, depending on opponent.
2. During this time, the input relay is seeing 12 volts. HOWEVER, the timer needs to either be PASSIVE-ON (on, but not counting), or not-yet-activated.
3. When the green light comes on, the transbrake is let go, and the input relay is de-activated. This is t=0.
4. the LED (or load in general) should be energized for T second, starting at t=0, ending at T.
5. The LED (or load in general) should then be de-energized.

Here's how it's set up right now, except I am manually shorting the input lead to the edge-trigger to power (does nothing) or ground (times from initial contact), and have an LED where the bottom relay should be (transistor output)

 

Look Back I had to edit.

No attachment just an explanation.

 

It's doign what I want, everything seems right- but it is riggering based on first contact, not contact removed. Like the edge-trigger circuit doesn't even exist.

 

It is supposed to trigger on "first contact".

The connection to the NC contact of the relay
hooked to the T-brake switch makes contact when
the T-brake is RELEASED. Contact is MADE when
switch is RELEASED. This is why the input is hooked
to the NC side of the relay. You added some connections
to the newest diagram that I don't think need to be there.
I think Post #53? has the original good idea.

Sorry about the attachment thing I am having trouble
on this end.

I hope I am not misunderstanding or leading you astray.

 

Maybe this will clear things up

 

It is supposed to trigger on "first contact".

The connection to the NC contact of the relay
hooked to the T-brake switch makes contact when
the T-brake is RELEASED. Contact is MADE when
switch is RELEASED. This is why the input is hooked
to the NC side of the relay. You added some connections
to the newest diagram that I don't think need to be there.
I think Post #53? has the original good idea.

Sorry about the attachment thing I am having trouble
on this end.

I hope I am not misunderstanding or leading you astray.

I'm trying to edge-trigger, so that it starts counting at end of trigger, not start

 

It is supposed to trigger on "first contact".

The connection to the NC contact of the relay
hooked to the T-brake switch makes contact when
the T-brake is RELEASED. Contact is MADE when
switch is RELEASED. This is why the input is hooked
to the NC side of the relay. You added some connections
to the newest diagram that I don't think need to be there.
I think Post #53? has the original good idea.

Sorry about the attachment thing I am having trouble
on this end.

I hope I am not misunderstanding or leading you astray.

Thank you. I am a certified dumba$$. It didn't don on me to make it hit ground when coil DE-energized. By edge trigger, i thought it would start at end of trigger- it just makes it a one-input deal. wow. I feel dumb now.

 

It is supposed to trigger on "first contact".

The connection to the NC contact of the relay
hooked to the T-brake switch makes contact when
the T-brake is RELEASED. Contact is MADE when
switch is RELEASED. This is why the input is hooked
to the NC side of the relay. You added some connections
to the newest diagram that I don't think need to be there.
I think Post #53? has the original good idea.

Sorry about the attachment thing I am having trouble
on this end.

I hope I am not misunderstanding or leading you astray.

just tested with the input relay, and it works. How did that not hit me in the head any sooner? :Stumped:

 

Whew, I hope it works as planned.

 

updated the pic in case it can help anyone else reading this.

The cap for that portion of the circuit shouldn't be a polarized electrolytic type. It will probably work ok, but a non polarized cap(the disc shaped ones are one version) would be preferred.

You can make two aluminum electrolytics into a non polarized one by connecting the two negative legs to each other and using its positive legs in the circuit. By adding the diode around R3 in my drawing the large opposite polarity voltage spikes are snuffed out(snubbed). So with a diode in circuit an electrolytic cap will probably have a reasonably long live.

To magnethead,
Add the diode on your edge trigger portion of the circuit as a measure
of safety before cycling that thing too many times that spike could
be a problem for the chip when repeatedly cycled.

Welp, it just blowed up. Guess I need some diodes, eh? Chip is blazing hot to the touch.

So what's my shopping list now? 10 2-watt rectifier diodes, 2 556's (a spare to keep on hand), 3 10Kohm resistors, 2 220-ohm resistors, am I missing anything?

 

I hope you were not running it without the
snubber/flywheel/protection diodes on the relays.

The snubber on the "edge trigger" portion probably
did not cause failure.

I am guessing the heat is from the HUGE timing cap
that you are discharging through pin 7 of the chip.
This is the reason I told you about the recommendations
for the R/C combinations for the timing portion of the
circuit in the datasheet way way back (maybe this morning?).
There are ways around this problem. I don't know of a
solution right off, but I am sure there is a solution

For now enjoy your smoking components, the next step
will be figuring out what happened and what to do about
it.

I'll check back later.

 

I hope you were not running it without the
snubber/flywheel/protection diodes on the relays.

The snubber on the "edge trigger" portion probably
did not cause failure.

I am guessing the heat is from the HUGE timing cap
that you are discharging through pin 7 of the chip.
This is the reason I told you about the recommendations
for the R/C combinations for the timing portion of the
circuit in the datasheet way way back (maybe this morning?).
There are ways around this problem. I don't know of a
solution right off, but I am sure there is a solution

For now enjoy your smoking components, the next step
will be figuring out what happened and what to do about
it.

I'll check back later.

I don't have any diodes at all..that's why there's 10 of them on my shopping list..LOL!

I'm not switching the relays with it yet. you think the 1000uf cap is what's causing the heat?

I don't know if this would effect the heat, but I don't have anything connected to the output pin of the other side of the 556, but everything else is there. Could the lack of connection be part of it?

For pin 5, does that capacitor also need to be a nonpolarized?

I'm going to finish wiring up the box itself, adding the LED's and such, I've pretty much finished the circuit board, now I have to do the inputs/outputs.

 

you think the 1000uf cap is what's causing the heat?

What do you think happens when you short circuit a "large" cap
charged to approx. 8 volts (2/3 Vcc) to ground multiple times.
There is a "transistor" inside the chip that shorts it to ground.
Somebody has to dissipate some heat.
We are getting past what I know. Somebody who knows or
GOOGLE will be required.

 

What do you think happens when you short circuit a "large" cap
charged to approx. 8 volts (2/3 Vcc) to ground multiple times.
There is a "transistor" inside the chip that shorts it to ground.
Somebody has to dissipate some heat.
We are getting past what I know. Somebody who knows or
GOOGLE will be required.

Damn. I thought that's what the resistor was for!

Thankfully, in use, it will only happen once every hour, for 8 hours, twice a week. hopefully it wont get so hot then.

for pin5, does that cap also need to be nonpolarized?

 

Damn. I thought that's what the resistor was for!

There is no resistor between pin 7 and cap.

Thankfully, in use, it will only happen once every hour, for 8 hours, twice a week. hopefully it wont get so hot then.

Intermittant use may work, you may only need a change of values
of the timing components to solve the problem. You can change these
values and still keep the same timing. A little thought now will
produce a better product.

for pin5, does that cap also need to be nonpolarized?

Yes, it should be. Ceramic caps in that range will probably only
offered "non-polarized".

I'm out till tomorrow.