help improve/convert my circuit to solid state

[strokedmaro]

Hello...I'm the new guy here and would like some input from the pro's out there. Attached is a section of a circuit I'm working on and would like to convert it to solid state. Basically, I need a way to do away with 5 bulky 12vdc automotive relays that don't handle vibration very well. Power requirements would be 12-13vdc @1amp or less for everything in the circuit.

First, I'm sorry about the picture but its the best I can do to show what I mean. Ok...the solenoids in the picture are ground activated. There are 2 modes controlled by the switch at the top of the pic.

In manual mode (RED) the ground from the switch energizes the top two relays...keeping automatic control signals (BLUE) from reaching the two solenoids. At the same time, the ground from the switch crosses over the de-energized contacts of the other 3 relays energizing both solenoids to give position 1 as shown in the legend. (other parts of the circuit create the other combos but I only want to focus on this part)

In automatic mode, the ground is removed by the switch de-energizing the top 2 relays allowing for computer controlled solenoid positioning (BLUE).
I also need help with the diodes...I'm not sure they even work this way so hopefully someone can give me direction. I basically need a component to block the (BLUE) automatic signals (grounds) from reaching the top two relays across the other 3 relays de-energized contacts (GREEN) This would chatter the hell out of those poor relays.

Im open to any ideas so don't be shy and thanks in advance for helping!!!

 

[ronsimpson]

>I am not clear as to “Position 1”, “Position 2”, “Position 3”, “Position 4”.

>I think:
>In automatic mode the two inputs at the top-right directly control solenoid A and B. >Ground=solenoid on.

>In manual mode the top-right inputs do nothing.
>Solenoid A & B are on.
>If the input to Relay 3 is +12 volts then A&B are off.
>If the input to Relay 3 is open then A&B are controlled by the inputs to relay 4 & 5. If open then solenoid is on, if +12 then solenoid is off.

OK do I have it right??????

 

[strokedmaro]

>I am not clear as to “Position 1”, “Position 2”, “Position 3”, “Position 4”.

>I think:
>In automatic mode the two inputs at the top-right directly control solenoid A and B. >Ground=solenoid on.

>In manual mode the top-right inputs do nothing.
>Solenoid A & B are on.
>If the input to Relay 3 is +12 volts then A&B are off.
>If the input to Relay 3 is open then A&B are controlled by the inputs to relay 4 & 5. If open then solenoid is on, if +12 then solenoid is off.

OK do I have it right??????

You got it! in manual mode the combinations for each position are dictated by energizing either relays 3, 4 or 5. In auto 3 4 and 5 do nothing and the positions are made by computer automatically.

Now, I just need a way to prevent the grounds from the computer (while in auto) from going through 3 4 and 5 and de-energizing 1 and 2. Im not sure if a diode works with ground signals. Maybe put it in backwards? What component could I use. Also, the resistors on 1 and 2 are supposed to simulate the solenoids when in manual so the computer doesn't throw up the red flag. Ive pretty much come to the conclusion that regular relays will be most cost effective at least in the prototype. If someone knows how to make this solid state please let me know or if you know what kind of diodes or other components I could use in their place to prevent the auto grounds from fluttering relays 1 and 2.....shout it out. THANKS

 

[ronsimpson]

First try!

>I changed your switch to a DPDT to make the logic ease.
>If the switch is in the up position then AUTO A/B controls solenoids A/B.
>If the switch is in the down position then input A,B,OFF control the solenoids.
>If A and OFF are open then current flows through R5 turning on Q3 and solenoid A.
>If A or OFF are at +12 volts then Q3 is off and the solenoid is off.

 

[strokedmaro]

PM sent....looks pretty awesome but need a little more explanation (for the new guy)

 

[ronsimpson]

Points +12 VOLTS and GND need to go to you source of power (battery). GND = cold side of battery.

A transistor is a device something like a relay. If there is no input current then the transistor is open (no output current). If there is input current then the output is on.

In auto mode control current flows from +12 volts through the solenoid through the switch to the point labeled “auto A” and to ground.

RED. Inputs A and OFF are at 0 volts or not connected. A small amount of power flows through R5 into Q3, turning it on. Solenoid current passes through Q3 to GND.

Blue. Input A is at +12 volts. A small amount of current goes into Q1 turning it on. In on mode Q1 steels away the input current from Q3. Thus Q3 is off (open).

Green. Input OFF is at +12 volts. A small amount of current goes into Q2 turning it on. In on mode Q2 steels away the input current from Q3. Thus Q3 is off (open).

 

[strokedmaro]

That is truly awesome...thank you very much..I have been reading a little trying to learn on my own and just have a question or two for my personal knowledge.
in you schematic, you've drawn in blue the 12 vdc from "A" to the base of Q1...it really goes through R2 then through the emitter of Q1 to the base right? If so, what prevents the voltage going through R2 to the emitter of Q2? Also, what is the purpose of the 2 diodes and finally, why are Q3 and Q6 different? Do they handle more current or something. Man, Im really learning a lot here...thank you!!!

 

[strokedmaro]

is there a way to modify this to allow a ground signal from "A" "OFF" and "B" to do the controlling rather than 12vdc?

 

[ronsimpson]

If inputs A & OFF (B & OFF) are not connected then the solenoid could be on.

If any input A or OFF is at 0 volts (gnd) then the solenoid will be off.

 

[strokedmaro]

I see your new schematic..

would this work for all intensive purposes? I sent you a PM

 

[strokedmaro]

I tried to do it myself with what I learned so far....

 

[strokedmaro]

by the way..when researching for the components to build this, I found several different variants. Like TIP41, TIP41A, TIP41C....prices were more than $2-3 different depending on last letter...whats that about. Where can I get transistors that will work for this project and what watt rating would you suggest for the resistors? Thanks!

Also, why the double diode's D5/D6; D10/D11?

 

[ronsimpson]

Any TIP41 should work A,B,C.
1/4 watt resistors.

 

[ronsimpson]

The modification you did probably will work. It has the same logic I used in my last post. My post=less parts--more diodes, simple to build.
Both do the same thing. When A is low it steels power form the TIP41.
I get parts from digikey.com

 

[strokedmaro]

Thanks for all your wonderful information!!! I do like yours better than the one I came up with (mostly borrowed from you ) , i just wanted to see if I understood the concept enough to come up with something that worked. Also so that I fully understand whats going on, can you please explain the purpose of the double diodes D5/D6 and D10/D11? Also diodes D2 and D3...I don't understand their purpose and would like to so I can try to design things by myself. THANKS AGAIN!!

 

[strokedmaro]

How hard would it be come up with a way to light either a digit or 4 seperate LED's that showed whats being commanded in both AUTO and MANUAL.
Some way of using gates to complete the following

Ground on solenoid A and B= Digit shows "1" or first LED lights (2,3,4 out)
Ground on Sol. B only = Digit shows "2" or second LED lights(1,3,4 out)
Neither Sol. has a ground = Digit shows "3" or 3rd LED on (1,2,4 out)
Ground on Sol. A only = Digit shows "4" or 4th LED on (1,2,3 out)

This would complete the entire project