555 timer to turn on 2nd 555 timer

Hi,
In the diag below I have 555 Timer A which turns on LED in 6 seconds and I have 555 Timer B that is basically what I need for a water rocket parachute deploy release. (started this new hobby with Grandkids). Both circuits work fine individually. My question is how do I "connect" the two so that A turns on B (in this example I would want B to turn on after the 6 seconds). Being new to circuitry I tried to connect various pins from one to the other--not doable. After googling I think this is possible but nowhere can I find a simple instruction on how to do this. I appreciate (and my Grandkids will too) whoever might be able to help me. Thanks, Richard

 

[MOD Note: fixed image orientation]
Note to @SeniorCitizen ... it helps people help you to have images that are easily read

 

Alec,
Thank you for the prompt detail reply.
Below is the "modification" I did. When I power up, the A timer waits 6 seconds and then the red LED lights up, but the B circuit doesn't seem to have power (I put a green LED to verify). Could you pls let me know if I mis-interpreted your above suggestion. If my diag of the mod is OK then I'll recheck and recheck my wiring. Not sure if this makes a difference, but I breadboarded "A" to one power rail and "B" independently to the opposite side power rail. And coming out of the 48K (with parallel diode (your note above)) I connected to the "B" power rail. Thanks, Richard

 

Alec,
Again....thanks a lot; here's more info:
1) please disregard the voltage on the diagrams; the battery supply would be 3.7 lipo battery)
2) initial state of A & B would be NO POWER
3) when A gets 3.7 vdc it begins to count down
4) At the end of 6 seconds A would then establish power (3.7 vdc) to the B circuit board
5) B would then immediately give a signal to the ServoMotor and the 60 degree (full travel) rotation would release the parachute.
6) B could stay in the power state until I retrieve the rocket.
7) the B circuit as-shown (which I found on-line) has two switches S1 and S2; I don't need the switches. I need to have that "switch-area" modified so that when power to B is established, the servo motor immediately turns-on and rotates the 60 degrees. While you were helping me with this A to B interface, I've been googling to find out how to do that (not sure how yet). There is another board MSP430 that does all this, but I want to use the inexpensive 555's

I hope I've answered all your questions.
Looking at my previous posts to you (I now realize) any question I post should have "full" details....sorry.
Thank you, Richard

 

Hi,
Thanks for the heads-up for a better approach. I will look into buying the CD40106.
To answer your question, yes the servo runs fine on the 3.7vdc (CW & CCW with enough poop to release a rubber band). I ran circuit B many times by itself. With that in mind could you let me know your suggested modification.
I appreciate your time.
Richard

 

Alec,
Had a few issues with the 555's incorporating the latest suggestion. However.....reason for the delay to get back to you.....that night I ordered CD40106BE as you suggested (preferred for this application). Anyway....I received it today (that was really fast) and was excited to set it up. Please see attached new modification. I hope I used the right terminals and that my "substitutions" for C2,C3 & pulse-width 10k pot are ok. (FYI, I checked battery voltage first (3.9v) and then tried combinations of both delay pot and pulse width pot. )
My latest observation/concerns:
1) The servo doesn't appear to move at all. (shouldn't it be moving CW or CCW after the delay ?)
2) Not sure if the delay part is working....since voltage (pin 8 to grd) appears immediately
3) What voltage tests can I do to check things out
4) The red light never comes on...I assumed it would light up after the delay
I've taken the breadboard apart 2 or 3 times....and the latest one, I made things very neat and spread out so I could trouble shoot....but I'm at a loss at the moment.
Thanks,
Richard

 

FYI, here's my breadboard (without power and servo wires connected for ease of viewing).

 

Thanks a MILLION Alec ! ! (redoing the capacitors in parallel did the trick). Using the cd40106 I am now able to have a delay, then rotate the servo...yippee.
One minor item... When the delay sends a signal to the servo, it rotates CW...which is fine. Then when I re-did it, the servo didn't rotate....I think because the servo was already in the full CW position. So I assumed I have to reset the servo back to the full CCW position before the next use. However I was not sure how to do that. With trial & error I figured out a "clumsy way" to reset it CCW.... by powering the circuit on/off multiple times quickly (before the red light came on) the servo moved a small amount CCW each on/off...so I did the on/off's until the servo was in the full CCW position. Then on restart...at the end of the delay, the red light comes on and the servo rotated fully CW. Is there a simple way to "reset the servo back CCW" before the next use.....some sort of a reset button thing. For example, when I retrieve the rocket, I could press a reset button, then shut the power off....ie. ready for the next use.

 

PS: the red light and servo ( both on the same pin as I originally had it) worked fine, so I didn't have to redo the red light source (however, thanks for the suggestion...it may come handy in the future).

 

Update to my "clumsy" approach. I put a switch between the servo and pin 8. So after the servo goes to CW, I then turn that switch OFF.....then I do the power on/off's towards CCW "without having to rush". When done going CCW, I then turn Power OFF and then turn that switch back to ON....so it's ready for the next use. It's still a clumsy for sure. Relative to your comment above, I look forward to your next reply.