how to lift and drop a pet door, motorized, remotely

[pebe]

Ok Garry. Here is the circuit. I have drawn it in colour to make it more readable.

On the left is the radio receiver. There are two relays marked A and B (I assume that the letters correspond with the letters on the two buttons on the transmitter, and that you will use A for ‘open’ and B for ‘close’). At the right is the 12V 3A power supply (I have not shown the mains power connection).

The 6 terminals at the bottom are the connections to the two relays that I have shown the wiring and motor connections for. ‘C’ is the common contact, ‘NO’ is the contact that is normally open, and ‘NC’ is the normally closed contact. You can see that the motor is connected between the two ‘C’s. As drawn, the door has closed and opened the bottom limit switch. No button is being pressed so both sides of the motor are normally connected through the relays to the –ve supply (assuming you purchased the receiver with the 'momentary' type of action), and the motor is stopped.

When you press the A button on the transmitter, relay A will change over so C connects to NO instead of NC. 12V is then applied to the left side of the motor via S1 and NO/C. As the right side is at 0V through C and NC, the door will start to open, and S2 will close. When the door gets to the top the top limit switch, S1, will open and stop the motor. When you release the button the relay will revert to normal. When you press the B button 12V will be applied to the right side of the motor so it will run in reverse, closing the door until the bottom limit switch, S2, opens.

D1 and C1 may not be necessary. I have included them because I don’t know what the starting current of the motor is. If it high enough to make the 12V supply voltage dip, then C1 will stop that dip being passed to the receiver and giving erratic radio reception. I suggest you try first without them (link across D1). The capacitor, C2, is to suppress any electrical noise from the motor brushes. Again, that may not be necessary and you could try at first without it.

The antenna of the radio receiver as supplied is coiled up. As you are using it at close range you could leave it like that. But if there are any reception problems, then uncoil it.

Check that the A (open) button actually works the A relay by measuring continuity between C and NO when the button is pressed, otherwise the limit switches will need to be transposed. When you are ready, set the door in the half open position and press the A button and check that the door opens. If it closes instead of opening, reverse the connections to the motor to change its direction.

I hope I’ve covered everything. Best of luck with your project!

[GaS753]

Pebe, just to give you an update - all of the parts you suggested for my project were ordered and in fact the fist one was delivered today! Thank you so much again for helping me, my excitement keeps growing. The US celebrates a holiday this day - so happy Labor Day. Garry (GaS753)

[GaS753]

Well I told you I was new to these blog things and after checking the site almost every day looking for your circuit, I just discovered the pages 1 and 2 at the site and going to page 2 discovered your circuit and instructions - wonderful. I am still waiting on the remainder of the parts I ordered, particularly the wireless gate garage opener remote control switch and transmitter. Hopefully it will arrive soon as I have received everything else. Your circuit looks great and again you have gone the extra mile. I can’t thank you enough pebe for all your help and hopefully I can get started soon and all will go well. Thanks again Garry (GaS753)

[GaS753]

Just an update pebe, I am still waiting for that wireless control and transmitter - it sure does take a long time for it to arrive. GaS753

[GaS753]

The wireless gate garage opener remote control switch and transmitter parts finally arrived but now I need some more help pebe if you would be so kind. I would like to send you a circuit drawing of how I understand what eBay sent with the part and the diagram you sent me but I don’t know how you did that. If there is no way you can explain for me I can write it all out for you but of course the drawing would make it much simpler. Thanks so much again for your continued help. Garry [GaS753]

[pebe]

Hi Garry,

I make up my circuits with the 'Paint' program supplied free with Windows XP. Someone else asked me how I used it so I wrote up a description for him.

I am not sure if it will work with Vista. Unfortunately the newer Paint program provided with Windows7 leaves a lot to be desired for this purpose, though the procedure is similar.

I could send you a copy of the writeup and the symbols I use if you care to PM me with your email address.

[GaS753]

That sounds great, and thanks for your usual quick response pebe, but I don’t have a windows machine as I use an Apple Mac so I couldn’t use your work. Do you have any other alternatives or should I just write it out longhand? What does PM me with your email address mean? Thanks so much again pebe. Garry [GaS753]

[pebe]

I can't help you with the Apple Mac because I've never used it. But there is probably a package for it that will draw a graphics image and save it as a .GIF file or similar.

PM means a Private Message. Just look at the right hand side of any of my postings and you will see a little icon with 'PM' beside it. Click on it and it will take you to a form where you can send me a private message. Just send me your email address there. Doing that in a PM means that people searching the internet and forums just to gain email addresses, will not be able to harvest it.

Not much point in that now though, as the writeup is of no use to you.

[GaS753]

Well here goes - since I have had no luck on the net finding a Mac circuit drawing program, but I will keep looking. - I hope I can write it all out correctly pebe. Thanks for the PM info.

If I look at the drawing eBay sent me of the Radio Receiver which looks much like your drawing of it, only with more detail. Beginning at the bottom with the 6 terminal posts spread across the edge - 3 for “Relay A” and 3 for “Relay B” marked left to right A B C A B C (this lettering of each terminal is not indicated on your drawing).

The way I understand the eBay drawing is that it shows:

Relay A - term A is the point where the red wire connects on your
diagram from the NO of Relay A to S1. [The red wire also connects from S1 to D1 and to S2 and the + side of the 12V power supply as well as it also connects D1 to the + side of the 12V power supply and + side of C1.
Relay A - term B is the point where the black wire connects on your diagram from the C of Relay A to the motor and to C2.
Relay A - term C is the point where the black wire connects on your diagram to the point NC of Relay A to C1 neg. and to the neg. side of the 12V IN of the Radio Receiver. [also jumped to Relay B - term C]

Relay B - term A is the point where the red wire connects on your
diagram from the NO of Relay B to S2. Then the red wire also connects from S2 to the + side of the 12V power supply and to D1.
Relay B - term B is the point where the black wire connects on your diagram from the C of Relay B to the motor and to C2.
Relay B - term C is the point where the black wire connects on your diagram to the point NC of Relay B and to the neg. side of the 12V power supply. [also uses the jumper to Relay A - term C]


the underlined portion refers to the Radio Receiver card to the left on your circuit drawing and what I believe is represented by the relay connections you have indicated in green

the bold portion - refers to the right side of your circuit drawing which is wiring I need to supply - something small like 16 guage ?

If I have it right pebe, I will begin putting it together. Thanks! Garry [GaS753]

[pebe]

I have been trying to find a spare receiver which I had, but cannot find it. So I cannot verify the connections. I would have thought it logical form the two switchable contacts would be A and B, with C being the common contact. But it would not necessarily be logical for the Chinese to use 'C' for 'Common'. Anyway, you must find the common for sure, so do it this way.

Power up the receiver, and do a continuity check with a multimeter on the A relay contacts between A - B, then A - C, and then B - C. Note which two gives a connection.

Now press the A button on the keypad and repeat the 3 checks. Again note which two contacts connect. The contact which is common to both results, is the contact that goes to the motor(marked C for 'Common' in my drawing).

The other contact that connects to it in the first test is the NC (normally closed) contact in my drawing, and the other contact that connects in the second test is the NO (normally open) contact.

The marking of the B relay contacts will be the same as for the A relay. To recap, the Common contact connects to the NC contact when the key is not pressed, but connects to the NO when the key is pressed.

You can use almost any flexible wire to make the connections.

I hope I have explained that well enough.

[GaS753]

I hope you are still available for some help with my project pebe. Everything is built and installed and works, at least partially. When the power is plugged in and the door is down and the button on the left (mine is marked with the symbol of a closed padlock) is pressed - nothing happens. So I lifted the door off of S2 and pressed the left button again - the door began to rise at a nice speed (you were right-on with your specs) stopping when S1 was engaged by the now raised door. Great! So I pressed the right button (marked with the symbol of an open padlock - A and B would be nicer) and the door began to close until it came into contact with S2 and the door was again closed. Great again! So now I pressed the left button again to have the door open - and like my first try - NOTHING. But if I raise the door manually off of S2 and the press the left button it raises up to the top - contacts S1 and the door stops - pressing the switch on the right causes the door to lower and close, stopping when S2 is contacted.
The problem is I can not get it to open again unless I manually lift the door off of S2 and then press the button. So what did I do wrong? My wiring seems correct per your circuit diagram but I may be overlooking something or do I have another problem? Like I said I need your help with this glitch but otherwise everything else is fantastic. Thanks again. Garry (GaS753)

[pebe]

Hi Garry,

It looks like it could be an anomaly with the receiver connections.

I assume you bought it on ebay. If so, could you tell me the transaction number (a long number normally found somewhere on ebay's acknowledgement of your order) so I can trace it back to the site, or preferably if you could sent photos of the front and back of its PCB.

[GaS753]

here is the item I bought http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... AQ:US:1123

We can get pictures if you still want.

[pebe]

Thanks for the info.

Could you please do another check. The decoder IC has the number SC2272T4, which I think is the correct one (temporary action and NOT latching action). Could you please confirm by releasing the radio button when the door is only half closed. The door should stop. If it continues to close then you have the latching type of decoder.

Can you confirm that S1 and S2 are of the 'normally closed' type, and go 'open' when the door hits them.

[GaS753]

Pebe, my daughter sent you the last reply with a link to what I bought on Ebay. I guess that wasn’t very helpful. After thinking about it all night I have additional info I hope will be helpful to send but will have to do it by photo which I will have my daughter do and set up the link and send it to you when she returns here.
I checked the decoder IC and the no. on it is SC2272T4, however when I released the button with the door halfway (up or down did not matter) the door did not stop. When the door hits either switch, it stops.
Thanks again for your continued good help. If need be, I can take the door mechanism apart and photograph both sides of PCB for you. Garry (GaS753)