SERVO OPERATED GATES

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stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

SERVO OPERATED GATES

Postby stearne » Sun Oct 06, 2019 5:23 pm

Hi everybody
Just been playing with servo's to operate my crossing gates for RECTORY ROAD it will be a 4 gate setup and wondering if any of you are interested in a circuit to control these servo's the circuit is based on 2 555 timers and 1 relay. I'm using 4 servo's hopefully gluing each gate to the servo arm I managed to find resistor value's to get 93 degrees on each servo, The little boards that LEDS on them are the servo slow control boards and I desolded the wires from these and soldered pins on to fit them to my pcb board, The servo's are worked in pairs 2- anti clock wise and 2- clockwise operated via the relay,
This is something for the future I'll also upload the schematic for this board
Attachments
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mossdp
Posts: 105
Joined: Tue Apr 10, 2007 2:25 pm

Re: SERVO OPERATED GATES

Postby mossdp » Sat Oct 12, 2019 3:05 pm

That looks an interesting setup. Do all gates open at once I wonder. I notice you have two timers so wondered what they both operate.

abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: SERVO OPERATED GATES

Postby abenn » Sat Oct 12, 2019 8:36 pm

I'm not familiar with 555 timers, but am a great fan of PICAXE programmable chips, and use a single 14M2 to control the two servos driving the blades on a single slip, and 08M2s for single servos on regular points. The 14M2 has enough outputs that it could drive the four servos for your gates without the need for the extra servo-slow boards, or even the relay. Servo speed, degrees of rotation, and sequence of opening/shutting would all be determined by the program loaded into the 14M2.

stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

Re: SERVO OPERATED GATES

Postby stearne » Tue Oct 15, 2019 7:55 pm

Hi abenn This is where I loose the plot I have'nt a clue when it comes to programmable chips I stick to basic electronic's using the 555 timer is a simple way to operate servo's the reason for 2 555's is one opens the gates 2 clockwise the other 2 anticlockwise the relay is triggered by my plug in block detectors if you have looked at my layout RECTORY ROAD Which triggers the first 555 when the detector goes off the other 555 closes the gates,The reason I put the servo slows on the board is just for neatness, I have modified this circuit board done away with resistors and added 4 trim pots in place to give me more adjustment on closing or opening the gates I have worked out that I need an 18K in one direction and 7.5K the other which gives me about 93 Degrees.
Mick

stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

Re: SERVO OPERATED GATES

Postby stearne » Tue Oct 15, 2019 8:04 pm

Hi mossdp As you may see I have anwered your question to abenn yes all gates operate at the same time, I have built a board for a 2 gate setup which includes a latching relay which is triggered by a micro switch from the first gate opening then bring's in the second gate to open, I am hoping to build a mock-up of the 2 types of gate in operation before the go on my layout.
Mick

abenn
Posts: 237
Joined: Thu Jun 05, 2008 11:03 am

Re: SERVO OPERATED GATES

Postby abenn » Tue Oct 15, 2019 8:48 pm

stearne wrote:Hi abenn This is where I loose the plot I have'nt a clue when it comes to programmable chips I stick to basic electronic's using the 555 timer is a simple way to operate servo's the reason for 2 555's is one opens the gates 2 clockwise the other 2 anticlockwise the relay is triggered by my plug in block detectors . . .
The PICAXE series of chips is supposedly an educational item, designed for schools, and programming is done using their Picaxe Editor software on your PC. It's dead simple, and never too late to learn :wink: But if you're comfortable with 555s and they do the job, then that's great.

stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

Re: SERVO OPERATED GATES

Postby stearne » Tue Oct 15, 2019 8:58 pm

Hi abenn maybe I'll try it one day so far I have managed I was chuffed when I used basic electronic's to build my block detectors which have turned out to be very robust compared to what I had bought off the shelf which did not last long at all.
Mick

Gordon H
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Location: UK
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Re: SERVO OPERATED GATES

Postby Gordon H » Wed Oct 16, 2019 12:45 pm

Looking at the circuit diagram, there seems to be nothing included to slow down the movement of the gates.
Do they simply swing from one state to the other (almost) instantaneously?

stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

Re: SERVO OPERATED GATES

Postby stearne » Wed Oct 16, 2019 6:19 pm

Hi Gordon The red leds on the small circuit boards are the servo slow's which are incorporated into my circuit board and are not shown on my diagram because they are the last item on leaving the circuit I have shown them above the diagram because generally they would be plug in units but I thought it would be neater to incorporate them in the board hope this answers your question.
Mick

Gordon H
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Re: SERVO OPERATED GATES

Postby Gordon H » Thu Oct 17, 2019 12:41 pm

Not come across those before.
Presumably they have a fixed slew rate programmed into them?
Ironically, if they have the capability of measuring the incoming pulse width and regenerating an interpolated version it would seem you could use the servo slow itself to do the whole job without needing any 555s at all.
You would, of course, need to be able to reprogram the servo slow to do this.
Out of interest, can you see a part number on the 8 legged device on the servo slow?
I suspect it will be something like a PIC12F675.

stearne
Posts: 35
Joined: Sun Jan 17, 2016 8:42 pm
Location: NEWTON GREEN, SUFFOLK

Re: SERVO OPERATED GATES

Postby stearne » Thu Oct 17, 2019 4:50 pm

Hi Gordon
I have taken one apart which I had shorted out I think its an IC Chip had to take the chip off to read it, Chip no/ HMCB047 and it covers on the board SOP8 Weather this means anything to you its a bit out of my reach, I looks like there only using 4 pins 1-6-7-8 the only other part on the board is a resistor and LED , This controls the speed of a servo but weather you can control the angles as well with this not sure, I'd like to know what you can fined out it maybe useful.
Mick


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