Steel Framed Sliding Gate (WIP)

[gwaithcoed]

What... Hey, whaddya know, there's a gate in that picture!

Gate ! what gate? I see no gate. Oh yes now I see it.

Seriously I think it's fantastic.

Alan.

 

[Fecn]

Thanks everyone for saying nice things about my gate - I'm rather pleased with the way it's looking myself.

My celebrity helper for yesterday was Liv Tyler - Liv has an excellent eye for angles, and she really helped out a lot. Here's a shot of Liv making sure the wood is prpoerly aligned with a 3mm gap, leaving me free to drill/screw from behind.

And here's what things were looking like at the end of yesterday. 20/44 planks now in place... and getting easier and easier as I go.

Work is quiet today, and the sun is shining once again, so I might go and get a bit more done.

 

[Fecn]

No celebrity helpers for the past couple of days, and I've had the weather in my favour, so.... It's finished.

Here's a shot from across the road...

Here it is opening.. sliding down the gap between the shed and the fence.

... and here it is from the back.

I've got three little holes to fill on the front where the drill managed to break through (insulation tape drill-stop failure) when I was pre-drilling screwholes, and there's a slightly wonky angle around about the middle of the centre line which I've deccided I can live with - Overall, I'm rather pleased.

When I ordered the Ipe decking boards, I initially ordered an extra 20% for wastage... then upped it to 50% figuring that any left-overs could become garden furniture. I'm rather pleased to say that aside from about 50 little triangles from the ends of planks, I've got virtually no wastage whatsoever, so I've got 19x3.05M planks left - I feel an outdoor table and chairs might be appropriate.

I've still got another day or two's work left on sundry bits... I'm going to put a couple of handrails from the shed to the posts to stop the nipper wandering down the back of the shed and getting in the way of the gate. Although a finishing touch, there's probably more woodworking skill involved in the handrail than there has been in the gate so far - I'm giong to use a router and everything

Incidentally, in the bottom left corner of the last pic, you'll see my pathetic 4.8V Black & Decker screwdriver - It was never great, and after it's NiCd died, it sat in my garage for a couple of years - somewhere on these forums, I saw someone else's tool mod and stole the idea. Instead of a 4.8V NiCd pack, it now runs from a variable 0-15V 25A (40 peak) power supply, and it's got a new lease of life. At 7.2V, it's an excellent tool with plenty of torque - Thanks to whoever I stole the idea from. I'm tempted to mod some more old cordless tools the same way.

Thanks again everyone for the kind words. Hope you're enjoying the pics.

 

[PowerTool]

Hope you're enjoying the pics.

Yep - been great to follow the build,watching the whole project evolve.Thanks for taking the time.

Nice celebrity helpers as well.. :wink:

Andrew

 

[Slim]

Very attractive gate. Well done.

 

[Philly]

Looks great!
Nice one,
Philly

 

[Dave S]

Very interesting project, and it looks superb!

Thanks for sharing

Dave

 

[Shultzy]

It looks great. The decking oil gives it a nice lustre.

 

[Fecn]

Although the gate itself is pretty much done, the project itself isn't quite finished yet. I'm planning on using some of the left-over wood to make a safety fence to prevent the little'un wandering down the back of the shed in the path of the gate... but right now, I've been busy making a few improvements to the remote control systems. I asked on the off-topic forum, and at least five people said they'd like to read about electronics, and since the moderators didn't complain, here goes.

Because of safety regulations and suchlike, the gate travels at a very leisurely pace and takes around 45 seconds to fully open or close. The remote controls that came with the gate have a pitifully limited range of about 100 feet, and that's nowhere near long enough for the gate to open before I get to it on the road. Motorists round here are very impatient, and if forced to sit and wait behind me for 30 seconds whilst the gate opens, they're likely to crash into each other trying to get past (They're forever trying to overtake my wife as she turns right into the driveway... 6 near-misses in 12 months) - I looked into longer range transmitters and radio antennas, but things started to look expensive, and you still had no idea if your button-push was successful and the gate was opening... then I had a better idea.

The gate motor kit came with a keyswitch - Turning the key in one direction is the same as pressing button-1 on the remote... in the opposite direction, it's button 2. Inside the box is just two microswitches, so a couple of relays seems an easy way to send button-pushes to the gate.

For a while now, I've had development/experiment PCB called a 'NetIOM XAP' - It's a neat little board centered around a PIC Microcontroller, and it provides a 10Mbit network interface, a bunch of inputs and outputs and a serial port. When connected to the network, the board uses DHCP to optain an IP address, and sends and receives commands using a simple UDP based protocol called XAP. Conveniently, I have a relay extension board which plugs on to the main board.. and some LEDs.

My company (which conveniently has an office at my house) uses an open-source phone system called Asterisk. It's a fully-featured PABX system with voicemail, hold music, call diverting, conference calls and much more, and has the advantage that if you're up to the task of installing and running it, it's free. Our office asterisk server sends/receives all calls via broadband to an Asterisk server which our central-london rackspace supplier provides for us. The setup means that we have a bunch of 0845 numbers to play and very little in call charges. The Asterisk system has a plethora of different ways that you can extend the functionality, but one of the easiest ones is called Asterisk Gateway Interface (AGI) which allows you to run scripts and commands when calls come in or go out.

It occured to me that I could do the following...
1. Assign the gate an 0845 number all of it's own.
2. Assign the gate's 0845 number to a speedial on my mobile (and wife's etc)
3. When a call comes in for the gate, pass the callerID of the incoming call to an AGI script - if the callerid is good, then the script sends out the XAP commands to turn on and off the relays, which in-turn act as the button pushes that open and close the gate.

Here's the bits of my asterisk extension.conf file which deal with the gate's 0845 number. The AGI script is called flash2.py and is just enough python code to get the NetIOM board to flash some lights. The script is run before the call is actually answered, and the call is hungup immediately, so it lasts for 0 seconds and costs 0 on my phonebills

[gate]
exten => s,1,AGI(/root/flash2.py)
exten => s,2,Answer
exten => s,3,Hangup

Time for some electronics...

The NetIOM board and relays need a 12V supply. My burglar alarm in the shed uses a 12V supply too, but rather annoyingly, uses non-rechargable batteries as it's backup. Since I needed to create a supply for the NetIOM board, I decided put a battery backup in too and use it to power both the alarm and NetIOM systems. I ordered a slimline 2.1AH Lead Acid battery for the job because they're dead easy to float-charge at 13.8V with a simple constant voltage charger.

I spent a while digging around through drawers and boxes, finding old power supplies from all manner of things, and even found a 13.8V supply, but most of them were a bit on the chunky side, and I eventually want to put all this in a nice neat box. One of the neatest supplies I found was a little 12V 1A plug-in switchmode which came with a CCTV camera.

Time for a for a 'Don't Try This at Home' - I've got the right equipment and experience to do this (relatively) safely. Do not even think about attempting this direct to the mains, even with fuses in the way. When I'm messing with these things, I'm using current limited bench supply and a small inverter to generate my own AC supply voltage. My setup means the maximum energy I can supply is a measly 3Watts, and the biggest shock I can get from the board is a measly 0.16Joules of energy.. I'd feel the shock, but I can't cook myself.

Switchmode power supplies all work in pretty much the same way - They all have a high-voltage side which does it's work at mains voltages, and a low-voltage side. They all take mains-AC and rectify it to around 400VDC which they store on a capacitor... then use high-frequency switching to turn on/off the current to a high-frequency transformer which in turn steps down to a suitable voltage, which is smoothed with extra capacitors and inductors to get rid of the switching frequency ripple. The low voltage side always has a feedback circuit which controls the light-emmitting-side of an Opto-Coupler.. and the Light-receiving side of the Optocoupler controls the switching signal on the high voltage side. (sorry if I lost you all there)

This is one of the neatest ones I've seen thanks to the rather amazing Viper22a chip buried in the middle. I took a look at the datasheet for it... 8-pin chip switching at 60kHz which does 9-25V at up to 40W, with no heatsink or extra drive transistors.
In the top left corner, you can see my very simple modification with an extra resistor, which increases the output voltage from 12V to 14.2V.. I will of course trim the legs and solder neatly before I'm done.

And finally, here it all is together...

There's a very simple battery charging/isolating circuit buried within the wiring. A 15ohm resistor acts as a very simple current limit device, and a diode prevents the battery discharging back through the the switchmode and lowers the switchmode voltage to about 13.5.. ideal for trickle charging. Two more diodes seprate the battery supply from the Switchmode and feed them to the same power cable.. which you can see here powering the NetIOM.

I've got a metal-lined plastic enclosure that's going to hold all this lot but I need to modify it to provide mounting points for the various boards. SWMBO and nipper are off galavanting this weekend, so I stand a good chance of getting this finished.

For extra points, I may also hook into the magnets and reed switches on the gate so I can work out if it's open, closed or somewhere in-between - Then I could use the information to decide what to do on the phonecall... If it's closed, open and hang-up... If it's open, answer the call and ask if you want it closing.

 

[ByronBlack]

Your just showing off now.

 

[DavidE]

Hi Fecn,

A very neat solution thanks for taking the time to note it all down.

With the hardware you have there is so much more potential to "play" too )

As an avid user of PICs I've never actually used the TCP/IP interface built into a PIC. This module certainly gives the functionality without the donkey work.

I hadn't really considered the potential of linking VOIP with the real world. Thanks for the idea - so much potential (always limited my thinking to the phone line and tones)!

Cheers
David

 

[Fecn]

Your just showing off now.

Well.. there's not a lot of point in making cool stuff if you don't show it to people and make them go Ooooh.

 

[Fecn]

SWMBO's away at the moment, so the evening has been mine. I found an old case which used to belong to a BT kilostream box back in the 90s. The box has a nice metal lining which nearly eliminates any RF issues.

I added a load of little brass stand-offs for mounting my PCBs - For the high voltage bits, I isolated things further with an extra plastic rectangle. I drilled a couple of holes and used some blobs of polymorph to give the backup battery a place to sit.

And here's the box right now (4:16AM) with the boards fitted into place.

I should be able to get new front and rear panels made up tommorow and get my I/O connectors fitted... then it's ready to put in the shed and hook up to the gate.

 

[Johnboy]

I don't understand a word of it but it looks very clever.

John

 

[Fecn]

I don't understand a word of it but it looks very clever.

The microchips and flashing lights make it look far clever than it really is... With the exception of the battery charging circuit, the rest of this is just an exercise in repackaging electronics into a dust-proof box which protect the bits inside from the dusty workshop/shed environment.

I needed some suitable plastic to make the front panel so a 20 year old broken keyboard became the latest victim of my dremmel.

I used the old facia as a template and cut roughly to size using the dremmel, then sanded back to the line using a belt sander followed by a sanding drum. I finished off with 320 grit silicon carbide paper which left a lovely finish on the edges.

Here's the finished article with the network sockets and pretty flashing lights mounted in place

And here it is all together.. minus the lids.

Time for me to go and sort out the wiring in the gate motor box whilst there's still a bit of light left..

 

[Fecn]

I ran an a shielded control cable through the existing conduits to the gate motor and wired in my 6 wires to the control inputs and lamp outputs.

And here it is in the corner of the workshop. The grey cable through the wall is the data connection from the gate which connects to my box of tricks through a 9-way plug. I'll screw it to the wall tommorow.

Amazingly, it all works and I can now open and close the gate from my PC. I went for the extra bonus points and connected up the inputs to read back the gate status, but I haven't done the relevant programming to read the inputs yet, so I don't know if that bit works.

And so, here ends my small diversion into electronics. As you can probably guess, this isn't the first electronics project I've done, but it is the most photogenic one. With the exception of the backup battery, everything else here was made from bits I had kicking around and old junk. I'm glad that at least a couple of you have enjoyed seeing this, even if I am way off the topic of woodwork here.

All that remains for me to do is the gate safety rails, so tommorow evening I shall swap soldering iron for SMCS and get on with some woodwork.

 

[DavidE]

Hi Fecn,

Looking good - if your anything like me... you'll probably be quite pleased with yourself for getting it in a box and almost finished now. I have so many half finshed projects or things in development. I sometimes have to switch due to higher priorities or I get bored with that particular thing etc.

All you need to do now is add the extra features... :wink: how about a proximity switch on the motor/gear teeth somewhere. You could then measure how fast the gate is opening. This could be used for condition monitoring in the short term in case it jams... or in the long term for trending the speed so you can see if some maintenance might be needed if it starts slowing down.
David

 

[lemonjeff]

Hi Fecn,
Got a few questions if you've a minute or 2 to spare, I like the garden table BTW (i'm not crawling, I really do like it.... honest) .

It looks like I will be going down the sliding gate route to span a 5m opening in front of my garage.
1. What span is yours?
2. What is the size of the RSJ and box section?
3. Is it easy enough to Open/Close by hand ? (i'm a tight wad)
4. What sections steels is the gate frame made of?
5. Does the top roller(s) run on a 20mm bar as well.
6. Lastly was the planning permission for the gate?

Jeff.

 

[Fecn]

Hi Fecn,
Got a few questions if you've a minute or 2 to spare, I like the garden table BTW (i'm not crawling, I really do like it.... honest) .

Thanks - I have to say I'm very pleased with how it turned out

It looks like I will be going down the sliding gate route to span a 5m opening in front of my garage.
1. What span is yours?

5536mm between the brick pillars, 5800mm for the whole gate.

2. What is the size of the RSJ and box section?

RSJ was 100mm wide x 150mm high... it was the smallest thing we could get hold of - It doesn't need to be big or strong.. just flat and level for round bar to be welded to and the gate to roll on the top of - The concerete's taking all the weight. - For the record, the gate support post is 150mm square.. the slam post is 100mm square - both of them go about 3ft underground.

3. Is it easy enough to Open/Close by hand ? (i'm a tight wad)

Yes it is - Because the wood I used is so dense and heavy, my gate weighs in at around 350KG.. but even still, I can move easily enough... In terms of resistance.. it feels like you're pushing a shopping trolley.

4. What sections steels is the gate frame made of?

The bottom rail of the gate into which the wheels fit is 100mmx50mm box section, the rest is 50x50mm

5. Does the top roller(s) run on a 20mm bar as well.

Nope - The top of the support post has 4 nylon rollers in a row - We welded an L-section to the top of the gate which sits over the rollers - Hopefully these two pics shows it OK.

6. Lastly was the planning permission for the gate?

Yes, permission was required in my area because it's over 1M high and visible from the road.

If you PM me with an email address I can send you copies of the plans, more photos, planning permission application, etc etc etc

 

[Lukey]

Looks very nice.

How are you fixing the planks to the frame?