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Adding push button to 2 way motor circuit

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I do not understand why you need the 5 volt power supply as your push buttons are connected between collector and emitter of the transistors. (This is my understanding.) It would be better if you post a schematic of EXACTLY how it is wired at the moment. Are you sure that the 12 volt supply is not dropping under load ?

Les.
 
This was the original drawing we worked from:

Relay 12V Polarity Reversal.gif


The original relays were automotive type to make sure we could handle the motor current and I have long forgotten if we even established the current load? As drawn this circuit should work fine. You need to look closely at your modifications to the original circuit. Something isn't quite like the picture as they say. :)

Ron
 
Hello Les and ROn,
I really think I shorted something when I soldered wires at the E/C poles of the board for the push buttons.
TY both for re-thinking it - my best choice is to make a new board, that will teach me to use different methods, different boards. This willt ake a few weeks until I get everything, but I have two relay boards I will use for a quick fix - will post new thread on it,
Again - you both have been very patient!

Les - the 5v comes form the MC (uC)

Rainer
 
It should work as drawn so something is amuck. :)

Ron
 
Ron,
I have ordered stronger relays and parts - so, new board will be made at some point, in meantime I will try the relay boards :)

Rainer
 
Q1 and Q2 are setup to drive the relay coils. The relays are common automotive 12 volt coil relays. The Q1 and Q2 base resistors were chosen accordingly. The relays can be had at any automotive store.

Ron
 
Was able to secure the relays - so, am starting to re-do the original circuit as well.
Question: if lights D3 and D4 (schematic at post #1) are actual automotive lights (high amp), will the resistor before the light still be needed?
 
D3 and D4 are standard red LEDs. If small low current 12 volt automotive bulbs are used the series resistors can be eliminated.

Ron
 
I am hoping this may be my last question for you all. And, I am thinking I asked it already but can not find where, so, here it is:
In schematic by Ron (post #1) the Lower and Raise are indicated as 5V (which comes from the uC/ MC.
Am I correct in thinking that I will have to send a negative/ neutral back to the uC?
This IS what I did in the original board. If I should not, this may have been my problem.
The uC I am using is: https://www.cainetworks.com/products/webcontrol/webcontrol-faq.html

Rainer
 
OK, now I see the remainder of the circuitry. You are using a web based controller. Here are the specifications for your controller:

Web Controller.gif


Note under Outputs you have 8 outputs, having an output level of 5 Volts (TTL) with a max current of 30 mA. You also have 8 digital inputs having a level of 5 Volts. Note TTL Logic Levels. You would send one of the outputs to Raise and another Output to Lower. You would run your limit switches to two of your digital inputs. So you send a Raise command, when Raise reaches full travel it will stop and the controller gets a logic signal telling it that Raise is at its limit, the same process holds true for Lower. You would write your controller code for any decision making. While a web based type controller would not have been my first choice it should work fine as long as you can write the code to support doing what you want to do and get it interfaced with your hardware. Yes, there will be a common or ground. Common or Ground on the uC board runs to the common of the circuit.

Ron
 
Good morning Ron,
TY - I needed to double check on the ground.
I have used the controller already and have written the code (which comes much easier to me than electrical circuits since I used to write my own patient care type program in FoxPro and then Access many years gone by :) )

Rainer
 
Yep, the grounds are common to each circuit. Cool on the controller.

Ron
 
I assume that the SPDT switches are controlled by the chicken coop doors, and know the 2N2222 transistors can handle the current required by the small underhood push-in automotive relays from fuse blocks.
 
I assume that the SPDT switches are controlled by the chicken coop doors, and know the 2N2222 transistors can handle the current required by the small underhood push-in automotive relays from fuse blocks.

Typical automotive relays have a coil resistance around 70 (low) to 85 (high) ohms and draw less than 200 mA coil current. The average 2N2222 can handle a collector current of around 800 mA. Worst case using the parts called out, I don't see exceeding 1/4 of the rated 2N2222 current. I don't even see a need for a heat sink on the 2N2222.

Ron
 
A 2N2222 cannot handle the current draw for a Bosch or similar-sized auto relay. I recommend a capable 2N1613/ NTE128.
As for the signal to the uC, it must know if and when a door switch is closed to avoid operation issues. Garage door openers have shut-off circuits, so too should this circuit.
 
A 2N2222 cannot handle the current draw for a Bosch or similar-sized auto relay. I recommend a capable 2N1613/ NTE128.
As for the signal to the uC, it must know if and when a door switch is closed to avoid operation issues. Garage door openers have shut-off circuits, so too should this circuit.

How much current does a Bosch automotive relay draw? Just a basic SPDT relay. Bosch no longer even manufacturers the relays, Tyco bought the rights from Bosch and here is what we get:

The most commonly used relay in car audio and security is the Bosch type relay (AKA: 5-pin relay, AKA: 5-prong relay, AKA: 5-terminal relay...). Although Bosch is no longer producing the relay (Tyco purchased the relay division from Bosch), it's still referred to as a Bosch relay. On this page, it will also be referred to as a Bosch type relay. The photo below is the bottom of the relay. Take note of the markings (85, 86, 87, 87a, & 30) near the terminals. 85 and 86 are the relay coil terminals. 30, 87 and 87a are the various contacts. This is a double-throw relay and has five terminals (two for the coil and three for the contacts). A single-throw relay would have only four terminals (two for the coil and two for the contacts).

Additionally:
Coil Resistance:
In a DC relay coil, the coil resistance determines the current flow through the coil. The current draw by the coil of a Bosch relay is ~0.160 amps (~75 ohm coil). In an AC relay coil, the resistance does not solely determine the current flow through the coil because the coil has inductance. The inductive reactance along with the DC resistance work together to limit the current flow through the coil.

Now call it a Bosch Relay if you choose but the coil current is .160 Amp and the coil resistance is about 75 Ohms. A 2N2222 will do just fine. You are looking at less than 1/4 of what a 2N2222 is rated for so why won't the 2N2222 work? Here is a link for my relay data. Never had a problem driving an automotive relay using a 2N2222 including continuous duty.

If you would like to redesign the circuit have at it.

Ron
 
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