Break Lighthouse apart?

[andersb79]

Hello
I am thinking of breaking a lighthouse apart ta make it moore integraded in the wall. Is there any pictures what it looks like when its open.

Deas anybody know if the lighthouse will continue to work if i put it inside the wall?

[Fraggboy]

I can't come across a picture of the Lighthouse, but I did come across a post from a member putting a Virtual Wall inside the wall. You can check that post HERE.

Hope that helps. I'm sure you can put a Lighthouse in the wall also..

[Julian]

I'll bring this thread back from its 8 month slumber because I have the same question. I'm interested in hearing from anyone who has dismantled either a lighthouse or a wall.

If no one has done this since this thread was last active then I might well be able to contribute the info myself in the next month or so. I just got my 560 today and, after one run, I'm seriously impressed with the 560 but somewhat dismayed by the lighthouses - they're ugly, ugly, ugly!

I plan to integrate Roomba(s) (soon to be plural) into my household so I plan to re-house the walls and lighthouses to be less intrusive if possible. I wish I'd seen Arnard's post (regarding burying a lighthouse in a wall) when I had builders in but for now I plan to just try to extract the electronics and re-house them in a much slimmer and more discrete housing. I also plan to reduce the housing size by locating the batteries remotely from the electronics so that that bulky part of the aparatus can be hidden in a cupboard and where I'm close to a power point I might even hook it up to a mains adaptor set at 3V. Hopefully the current consumption is low enough for voltage drop over longer supply cables to not be a problem. Depending on what I find when I get inside, and issues with wire resistance, I might be able to take this to it's logical conclusion and hide everything in the cupboard and just have the IR transmitters on extension wires and all of the rest of the device in a cupboard.

Anyone who has gone here before me, please do post any pictures or advice that you can offer, otherwise stay tuned (it might be a month or so I'm afraid, my life is a bit busy right now) for my experiences.

- Julian

[vic7767]

To gain access to the inside of the LH/VW will require one to pry off the oval plastic ring on the top of the accessory. Once removed then you can get to all the mounting screws and tear that unit down. You can also use 22 or 24 gauge solid copper wire (Telephone) for medium transport of dc voltages.

[Julian]

Thank you Vic. I see that ichris posted a picture in another thread (http://www.robotreviews.com/chat/viewto ... =20#p63026) that shows the lighthouse dismantled one stage further. For the convenience of others finding this thread, here is the picture he posted:



I've got almost to the same stage of dismantling (I haven't got the black plastic cowling off the Halo LED yet) but already I'm disappointed to see that the main PCB is that quite bulky oval shape that can be seen in the picture above.

My overall aim is to create something that can be mounted in a much lower profile casing that sits squarer and more flush to the wall. I also have a second disappointment; I read that the Halo LED does more than collision avoidance, it is crucial to the traversing protocol. People have reported that when the halo LED is taped over then the Roomba will not successfully traverse the lighthouse. I'd hoped that I could ignore the Halo LED but it appears that I can't.

In light of my discoveries, my latest plan is to snip off all 4 LEDs from the PCB (leaving the Fence and Tractor LEDs all mounted into the black holder shown above) and then re-connect them to the PCB via 8-way alarm cable such as http://www.maplin.co.uk/module.aspx?moduleno=65. The LEDs should then fit into a very discrete housing with the alarm cable running a few feet (it might need to be about 6 feet so I hope the extra resistance won't break anything) to another box whose size I don't really care about because it will be totally hidden away.

- Julian

[ichris]

I'd also working to re-house my LH's. It's true that the halo is required for transversing.

My plan is to mount the LH circuit board in a small enclosure and mount that in/on the wall, with just 2 wires going to a remote AC power supply. No more batteries!

For your idea, all the LED's probably run off a common ground (but I have not confirmed this) - you may be able to get away with 5 wires instead of 8. It is difficult to get to the LED's from the bottom of the circuit board. This area is covered by a Zigbee radio circuit board. I think you'd have to unsolder the radio to unsolder the LED's. It may be easier to remove the LED's from top of the circuit board.

You will also need to rig some sort of on/off switch because you have to re-pair the LH every once in a while.

I've already build and tested a remote VW. I put the LED in a usb flash drive housing, mounted that flush on a wall, and ran wires thru the wall to a VW circuit with AC power supply. A VW only needs one LED and the halo is not required, so it's an easier mod. It's nice to eliminate that large housing and batteries!

[Julian]

Thanks Chris, for this.

It's great to hear that there is at least one other person (you) doing what I'm doing. Personally I think that it could add a nice bit of additional revenue to iRobot's sales if they offered an aftermarket "designer" lighthouse via the accessory shop for people who don't want things that look like props from Buck Rogers or Flash Gordon scattered around their floors. I would happily pay a 50% premium over the current unit, possibly more, for a discrete LH/VW of the type we're trying to build.

I definitely do plan to cut off the LEDs above the PCB with fine wire cutters rather than try to get to the bottom of the PCB to unsolder. I then plan to solder (or maybe crimp connect) my extension wires onto the remainders of the LED's metal legs which will at that point be sticking up about 10mm from the PCB. In some cases I might not even re-use the LEDs I cut off because I don't need much power for a VW that will be in a 3 foot corridor, and I don't need the Tractor LEDs, so I might just use a single new 3mm LED for that (I already bought some to experiment with) which would make the skirting-board mounted unit even smaller.

I had also considered that all the LEDs might have common grounds to reduce wiring. I also wondered whether the two Tractor LEDs are ever switched separately or whether those might have both common ground and common drive connections which, if so, would reduce the wire count even further.

I may or may not add a power switch because I think the need to reset the electronics to force re-pairing will be very infrequent. As many of the devices as possible will be running off an AC power adaptors (3V DC output) so for those I'll just toggle the mains feed if I need to reset them. The ones that aren't close to a convenient mains supply will have batteries in the hidden box containing the electronics so I'll probably add a power switch to those, depending on enclosure space; the alternative is to open up the box and pop the battery which, for a once-every-6-months operation, isn't a disaster.

You've obviously tried it and it seems OK but, according to the description of how the LH/VW unit works, I had some concerns about not having the Halo LED on a VW. I'd be interested in your (chris or anyone else's) comments. In all that follows, when I say VW, I mean a LH set to VW mode, not the older basic VW-only unit.

My first concern is pairing. The Halo LED seems to be integral to the pairing protocol so a Halo-less VW would switch on when any Roomba starts a mission (the Roomba switches on its own already paired devices and also all currently unpaired devices). This means that the device will switch on OK but does it switch off? I'm guessing there's a power-off timer in case a device misses an explicit power-off message from the iRoomba so maybe that handles that.

My other concern is that, during a mission, the Roomba wants to go up and talk via IR to every LH it discovered from the RF interactions at the start of the mission. Does it only really care about about LHs or does it care about VWs as well? Does it even know the difference at the RF discovery stage? When the devices make themselves known at the start of the mission via RF discovery, does the protocol include information as to whether a device is in LH or VW mode? My concern here is that if I have a Halo-less VW then it will be discovered via RF but will never be physically identified and tagged by the Roomba during the mission so might the Roomba always think that there is one more room to clean (one more LH to traverse) because of this missing device that it never found via IR?

- Julian

[ichris]

Wow, those are good questions. My custom VW is based on v4 VW, e.g. "dumb" and not paired to any bot. It's AC powered, so it's always on. I have two bots and the VW blocks entrance to/exit from a hallway. I don't want either bot to cross that VW, so a v4-type VW works fine for me.

FYI - when a v5 VW is on, all bots recognize it and won't cross it, even if the bot is not paired with the VW. Both my bots run on the same schedule, so a v5 VW would be on when both are running. Besides the power on feature, I'm not sure what the usefulness of a paired VW is. Perhaps to have two bots on different schedules clean the same room?

Keep us (or maybe just me) updated on your re-housing results. Remember that the LED's have to be about 3.25" off the floor to shine into the bot IR lens.

Another idea I had is to mod a LH to be a LH one day and a VW another. This could allow one bot to clean more rooms than it would be able to on one battery charge. The custom LH/VW would be used in pairs, allowing rooms A and B to be cleaned on alternate days. I think the LH/VW switch could be electronically switched without getting into the IR/radio protocols.

[Gordon]

...I had also considered that all the LEDs might have common grounds ...

Based on the wiring seen in the 2004 vintage VWU, I would be wary of such an assumption. If interested, view its schematic here, and you will see the two IREDs are located in their xstr driver's collector ckts. IOW, they have a common Vcc, not GND. Values of emitter resistances are used to set or adjust radiant power outputs. The halo's IRED has a fixed output, but the fence-IRED's output is range switched by changing the emitter resistor. I think it is quite likely that iRbt made use of that design in the 5XX LH/VWU design. Proof is TBD, of course.

Regarding this:

...Does it even know the difference at the RF discovery stage? When the devices make themselves known at the start of the mission via RF discovery, does the protocol include information as to whether a device is in LH or VW mode? My concern here is that if I have a Halo-less VW then it will be discovered via RF but will never be physically identified and tagged by the Roomba during the mission so might the Roomba always think that there is one more room to clean (one more LH to traverse) because of this missing device that it never found via IR?,..

Should you not be able to discover that effect yourself, by opaque masking the omini-directional optic on one of your LH/VWUs on a trial basis?

[Julian]

...I had also considered that all the LEDs might have common grounds ...

Based on the wiring seen in the 2004 vintage VWU, I would be wary of such an assumption. If interested, view its schematic here, and you will see the two IREDs are located in their xstr driver's collector ckts. IOW, they have a common Vcc, not GND.

Thanks. I'll check more thoroughly but that looks encouraging. It doesn't matter whether it's Vcc or Gnd that's common when it comes to reducing the wire count to the LEDs, either one will do as long as I get it right as to which one.

...Does it even know the difference at the RF discovery stage? When the devices make themselves known at the start of the mission via RF discovery, does the protocol include information as to whether a device is in LH or VW mode? My concern here is that if I have a Halo-less VW then it will be discovered via RF but will never be physically identified and tagged by the Roomba during the mission so might the Roomba always think that there is one more room to clean (one more LH to traverse) because of this missing device that it never found via IR?,..

Should you not be able to discover that effect yourself, by opaque masking the omini-directional optic on one of your LH/VWUs on a trial basis?

Yeah. I will do experiments. I was just trying to save myself time in case someone had already been here before me or had intimate knowledge of the protocol (the latter would have to be a current or ex iRobot engineer I think).

I have 3 more LH/VW devices shipped out to me today so they should arrive tomorrow (along with my new Scooba 385 ... excited!). I don't think I even need the masking tape. I currently have the two LH/VWs that came with my first (and currently only) Roomba (a 560) so right now its cleaning zone is the sitting room which has the docking unit in it and has a LH at the door. Once through the LH it gets into my hall where I keep all the other doors off the hall closed and the second LH is set to VW mode and blocks the corridor going back to the bedrooms. The current cleaning pattern is simple, it cleans the living room, traverses the LH, cleans the hall, and then crosses back over the LH and docks. So far it has never failed to complete a mission and dock successfully at the end.

The experiment I will try is even simpler than you suggest. When I get my new units I will just carry one right back into one off the bedrooms (way beyond the virtual wall), set it to VW mode and put batteries in it. I will then launch my Roomba for a cleaning mission. Roomba will switch it on at the start of the mission and will know that there is a third device out there but it will never encounter it during the mission. If things behave as I hope then Roomba should still dock back in the sitting room about an hour after mission start (2 x 25 minute cleaning cycles plus about 5 mins to get back to the LH and another 5 mins to find the dock once back in the sitting room). If the experiment "fails" (as far as I'm concerned) then I should find an expired Roomba in one of the two rooms still vainly searching for the missing third device.

If the above experiment goes the way that I hope it will then, out of interest, I will repeat it again but this time with the third "concealed" device set to LH mode. In this circumstance I would expect to find an expired Roomba still looking for that other LH.

- Julian

[Julian]

Besides the power on feature, I'm not sure what the usefulness of a paired VW is. Perhaps to have two bots on different schedules clean the same room?

Keep us (or maybe just me) updated on your re-housing results. Remember that the LED's have to be about 3.25" off the floor to shine into the bot IR lens.

I will keep the forum updated but it may be a few weeks because next week is going to be very busy for me.

Regarding the usefulness of paired lighthouses, one possibility is that it allows you to create an overlap area such as I proposed for my "choice 3" in this thread: http://www.robotreviews.com/chat/viewto ... =1&t=11599. I suppose another advantage might be a longer battery life. I need to experiment to find the power-off behaviour with unpaired devices but my random guess right now is that at the end of the mission the Roomba explicitly switches off all its paired devices but any unpaired devices that it woke up at the start of the mission but never encountered (and are hence still unpaired) might rely on some internal timer to switch them off after a certain time with no RF detected so they may stay on loger after a mission. I will get the answer to this question, as well as others, once I have performed the experiments I described in reply to Gordon's post above.

Another idea I had is to mod a LH to be a LH one day and a VW another. This could allow one bot to clean more rooms than it would be able to on one battery charge. The custom LH/VW would be used in pairs, allowing rooms A and B to be cleaned on alternate days. I think the LH/VW switch could be electronically switched without getting into the IR/radio protocols.

Hmm. I've yet to decide whether you're a kindred spirit or a bad influence! A bit of both I suspect. I hadn't thought of that one but I was wondering about using a single LH in VW mode, along with an electronic timer, to create a movable VW so that at some times of the day it was driving a particular remote-mounted Fence LED and at another time of the day it switched to driving an alternative remote-mounted LED in a different location. This might be a cheap and effective way to implement my "virtual wall with no dead zone in it" concept in the thread I referenced above.

I must give more thought to possible uses of the electronically switchable LH/VW for my setup but, from looking at my partially dissected unit, I would say that it should be easily achievable just using a relay to simulate the switch contacts and some sort of simple two event 24 hour timer (one event being switch on the relay and the other event to switch it off).

- Julian

[Julian]

My custom VW is based on v4 VW, e.g. "dumb" and not paired to any bot. It's AC powered, so it's always on.

Chris,

My Scooba just arrived today so I am now also the proud owner of a dumb v4 VW and I'm planning what to do with it. You say above that your VW is "AC powered, so it's always on.". I'm confused about this since I thought that the dumb VW had an automatic power off after a certain time. Is it really always fully on, i.e. the Fence LED is always active, or do you need to press the start button before a mission to wake it up?

I waited to get my dumb VW before asking you this because I thought that maybe the device had an alternative input for an external DC power source and so would know if it was being fed from an AC supply rather than batteries but mine doesn't seem to have this so I assume that you just applied the 3V DC to the PCB from a power brick instead of the batteries, in which case how does the VW know it's not on batteries and should never power down? I haven't cracked the case yet so is there some sort of switch inside to disable the auto power-off feature?

- Julian

[ichris]

Hi Julian - good luck with your "super soaker" Scooba! I have one also.

The "always on" VW I was talking about is a home made VW, I built it myself. The IR signal it sends out is based on the v4 VW IR signals. All bots with IR heed the v4 and v5 VW signals, even though the v4 and v5 IR VW signals are different.

I built my VW for 3 reasons - fun, eliminate the bulky "floor wart", and use AC power. I did not re-house a existing eyeRobot VW, it's all new pieces/parts.

DIY VW thread: http://www.robotreviews.com/chat/viewto ... f=4&t=1178

I'll be adding my DIY VW to that thread sometime (got to take more pictures). The v5 VW/LH IR/RF protocols are so complex I doubt there will ever be a DIY v5 VW/LH. (someone prove me wrong please!)

The Scooba has no way to automatically turn on (no Zigbee radio) a v4 or v5 VW. But if a v5 VW was turned on from another bot, the Scooba would see the VW signal and not cross it.

You are right about the auto-off feature on the v4 VW. You have to manually turn them on. I think it's supposed to automatically turn off after 110 minutes. Or you can just turn it off manually. They have no external power supply connection. There are no switches inside to disable the power-off feature.

FYI - they use alot of power in "max" range mode. I measured it once, it was something like 750 milliamps. Don't remember power draw at other settings.

[Julian]

...Does it even know the difference at the RF discovery stage? When the devices make themselves known at the start of the mission via RF discovery, does the protocol include information as to whether a device is in LH or VW mode? My concern here is that if I have a Halo-less VW then it will be discovered via RF but will never be physically identified and tagged by the Roomba during the mission so might the Roomba always think that there is one more room to clean (one more LH to traverse) because of this missing device that it never found via IR?,..

Should you not be able to discover that effect yourself, by opaque masking the omini-directional optic on one of your LH/VWUs on a trial basis?

Yeah. I will do experiments. I was just trying to save myself time in case someone had already been here before me or had intimate knowledge of the protocol (the latter would have to be a current or ex iRobot engineer I think).

I got three new lighthouses yesterday so I've done my first experiment. I set my Roomba on its standard 2-room cleaning cycle in the rooms below.

The only difference this time is that I installed the batteries in one of my new lighthouses, set it to VW mode, and sat it on the bedside table in my bedroom (way away from the rooms where Roomba was cleaning, probably about 15 metres from the docking station where Roomba started it's mission and there's absolutely no way Roomba would have ever got close to seeing any IR transmissions from it).

What I wanted to determine was (a) whether Roomba would consider it a mission objective to locate it and hence not return to the dock because it never considered its mission complete, and (b) what the power-off behaviour would be at the end of the mission since this extra hidden VW, having never been introduced to the Roomba during the mission, would still be unpaired at the end of the mission.

What I discovered is that the extra lighthouse didn't disturb the normal running of the mission at all. Roomba spent 25 minutes in the first room, then an extra 3 minutes to find the LH at the doorway, spent another 25 minutes in the second room, and then a total of 5 minutes to traverse the LH again and get back to the dock.

For power off behaviour I found that Roomba switched off the unpaired VW at the end of the mission along with the paired LH and paired VW (which actually could be an issue if two Roombas were running missions at the same time but for me it is exactly the behaviour I was hoping for.

My conclusion so far from this is that if I want to modify a LH to create a VW with the LED mounted remotely from the bulky electronics casing then it will work just fine to not bother with the Halo LED at all (and obviously not the Tractors) and to mount the Fence LED alone in some sort of very discrete skirting board mounted enclosure.

Out of interest I now plan to do three more experiments over the next three days. The setup for each experiment will be identical to that described above except for the status of the third hidden device in my bedroom (hidden = able to do RF comms but isolated from any IR interaction with the Roomba) .

Tomorrow's experiment will be with the hidden device remaining unpaired but this time set to VW mode instead of LH mode. Will Roomba now consider it a mission objective to find it?

Monday's experiment will be to switch the third device back to LH mode but this time to briefly activate Roomba prior to the mission and let it pair with the third device and then go and hide it in the bedroom prior to launching Roomba on its 2-room mission. I'm only doing this one for completeness because I would be amazed if that didn't behave exactly as today's experiment did.

Tuesday's final experiment will be to switch the now-paired third device to LH mode and again see if Roomba now considers it a mission objective to find it and fail to re-dock if it doesn't.

- Julian

[ichris]

It's not a LH, but here's my "embedded" virtual wall. I put the VW LED in some cord conduit and ran a cable from the VW electronics to the LED.

VW IR LED

DIY virtual wall

It would be even better to drill a hole in the wall and put the LED in the hole.

More info here: http://www.robotreviews.com/chat/viewto ... =60#p65658

The same concept could be used for a LH.

[Julian]

Another idea I had is to mod a LH to be a LH one day and a VW another. This could allow one bot to clean more rooms than it would be able to on one battery charge. The custom LH/VW would be used in pairs, allowing rooms A and B to be cleaned on alternate days. I think the LH/VW switch could be electronically switched without getting into the IR/radio protocols.

I had a look at this, it's a fantastic idea that I can now see uses for in my environment and I also think that it's going to be really trivial to do.

I looked at the VW/LH selector switch and the PCB routings on my opened-up LH. The selector switch is just a single pole double throw switch and even better it doesn't even use one of the contacts so it's essentially an on-off switch. My LH has black, yellow and grey wires running from the switch PCB to the main PCB. The black is GND, the grey is the supply to the Fence LED, attenuated by the appropriate resistor depending on the setting on the range switch, and the wire of interest is the yellow (middle) wire which controls the LH/VW mode and it's really simple. When the selector switch is set to VW mode then the yellow wire is grounded and when the selector switch is in LH mode then the yellow wire is floating (open circuit). I assume that there is a pullup resistor on the main PCB that pulls the yellow line up to Vcc (or something) when the selector switch leaves it open circuit.

What I would suggest as the simplest (although admittedly not cheapest) solution is to get something like this (appologies for a UK link, it's easiest - http://www.homebase.co.uk/webapp/wcs/st ... 3E24+TIMER) and wire the outlet to a simple mains relay that, when activated, connects the yellow sense wire running into the main PCB (the wire should be disconnected from the switch PCB) to ground (which could be tapped off the battery/PSU feed). Then all you need to do is program the timer plug to switch on whenever you want VW mode and off to revert to LH mode. I doubt that the whole thing would take more than 10 minutes to build.

One point; be sure to set the timer to make any mode switch before a mission starts. I discovered in my experiments that, once a LH/VW has been identified (via IR) by a Roomba then that device's LH/VW mode is locked for the duration of that mission and changing the selector switch mid mission won't change the mode. If the Roomba has already interrogated the device during the mission then it doesn't feel the need to do so again during that mission so it will never detect that you have changed the mode and will continue to interact with that device on the basis of the setting it read when it first met it. Everything resets of course when the mission is over and it gets back to the docking station.

- Julian

[ichris]

I'm glad you have a use for this, but it would be safer to put a 3V transformer on the wall switch, e.g., a UK version of:

http://search.digikey.com/scripts/DkSea ... 975-P7P-ND

This power supply could power the LH and the relay. You want to limit exposure to mains power as much as possible for safety reasons.

I'd personally use an optoisolator instead of a relay, but there are many good ways to do this.

An even simpler use for the wall timer is to turn off the dock after the mission starts. This way, when the robot returns to the room the dock is in, it will clean that room until the batteries run out. Many people do not like the 25-minute per room limit. If the dock is in a large room, this is very helpful. The wall timer can be set to turn the dock back on 3 hours later, ready for you to manually set the bot back on the dock.

Cheers mate! (that's British, right?)

[Julian]

I'm glad you have a use for this, but it would be safer to put a 3V transformer on the wall switch, e.g., a UK version of:

http://search.digikey.com/scripts/DkSea ... 975-P7P-ND

This power supply could power the LH and the relay. You want to limit exposure to mains power as much as possible for safety reasons.

I'd personally use an optoisolator instead of a relay, but there are many good ways to do this.

An even simpler use for the wall timer is to turn off the dock after the mission starts. This way, when the robot returns to the room the dock is in, it will clean that room until the batteries run out. Many people do not like the 25-minute per room limit. If the dock is in a large room, this is very helpful. The wall timer can be set to turn the dock back on 3 hours later, ready for you to manually set the bot back on the dock.

Cheers mate! (that's British, right?)

Point taken re AC but personally I'm pretty comfortable working with it.

Interesting idea re turning off the dock but one thing occurs to me. Won't letting the Roomba clean until it is exhausted initiate a 16-hour charge cycle every time? I know that a 16-hour charge cycle is recommended on occasion to keep the battery conditioned but is it a good idea on every mission? Do NiMH batteries mind having frequent deep discharges? I thought that was one of the advantages of Li-Ion that they are more tolerant to this but I'm most definitely not an expert on battery chemistry.

Your British is impeccable by the way. We'll have you drinking warm beer next.

- Julian

[ichris]

Won't letting the Roomba clean until it is exhausted initiate a 16-hour charge cycle every time? I know that a 16-hour charge cycle is recommended on occasion to keep the battery conditioned but is it a good idea on every mission? Do NiMH batteries mind having frequent deep discharges?

I manually block my dock occasionally and haven't noticed that it ever triggered a 16-hour charge. I'm not sure what the conditions are to initiate a 16-hour charge.

Also not sure if running the bot 'till it stops is considered a deep discharge, or if such a thing is bad for NiMH. I think the bot stops before the voltage gets low enough to be considered a deep discharge.

Already love Guinness! Cheerio!

[mfortuna]

The roomba stops when the pack gets to 12V which is an average of 1V per cell. The normal cutoff voltage for a nimh cell is .9V which would be 10.8V. Because of the large number of cells it is possible some cells dip below .9V which is not good for them.