Best Web Content Filtering using a cheap WIFI Router

OpenDNS is great for web content filtering, but it cannot enforce safe search nor youtube restricted mode. Of course, you can disable all search engines and all video sites.

Google did provide a mechanism via DNS to enforce safe search and restricted mode on your network, which OpenDNS cannot implement. The solution is DD-WRT. You can buy a WIFI router with DD-WRT as the OEM software. Somebody sells routers preinstalled with it, or you can replace the OEM software yourself.

The router can be very cheap. You don't need to give up your current super duper routers. You just need one DD-WRT router to be the final gatekeeper to the internet. You just need fast switching and a higher bandwidth than your ISP link.

Inside DD-WRT, under the Services tab, you can add the following to the additional DNSMasq options:

address=/www.google.com/216.239.32.20
address=/www.youtube.com/216.239.38.120
address=/m.youtube.com/216.239.38.120
address=/youtubei.googleapis.com/216.239.38.120
address=/youtube.googleapis.com/216.239.38.120
address=/www.youtube-nocookie.com/216.239.38.120

That is all! Being DD-WRT, I would be very careful about extra spaces. The 1st line redirects to the IP of forcesafesearch.google.com. The rest are Google's instructions to redirect to the IP of restrict.youtube.com. You can also redirect to 216.239.38.119, the IP of restrictmoderate.youtube.com.

These settings are independent of OpenDNS, but much better with it. At the OpenDNS settings, you should disable search engines and video sharing. Then you whitelist, never block, just google and youtube:

forcesafesearch.google.com

google.com

youtube.com

Unfortunately, if your kids are smart enough to bypass the DNS on the router, you have to be smarter to disable their DNS request. In DD-WRT, it's under the Access Restrictions tab. You add a policy that filters out some services. You select dns under the Blocked Services section.

Under the list of clients, you should enter all phones, computers, and tablets that access the internet. You can use MAC's, IP's or range of IP's. 

The most important warning for DD-WRT is that what you see may not all work! There are multiple underlying chipsets that are not compatible. The software is probably written and tested by very few people. In brief, buy a recommended model, and flash only the recommended DD-WRT version.

For my DD-WRT, access restrictions on MAC and IP all don't work. Only a range of IP's work. MAC's are unique for each machine but IP's can change with automatic assignments by DHCP. You can map MAC's to IP's in a central place under the Services tab, DHCP Server, Static Leases.

Enjoy!

Window Tint Removal Using Steam

I tinted the car window myself using the very popular Gila product. I did the windows in my home but car windows is a different animal. I did it badly but let it hanged on for a year. Because I thought it's difficult to take it out with glues on. I brought the Gila remover but it sat in the garage.

To save time and to not touching chemicals, I brought it to a tint shop. Because retinting it would take a few minutes for them for cheap. But the problem is, to remove the tint it could take up to 3 hours! It would be the worse case I suppose, with professionally installed tint with super duper glue. Since I didn't have 3 hours, I passed.

Luckily I consulted the internet. Steam is the word. It made a lot of sense. I already have a big steamer with a lot of accessories. I didn't even remember the capacity but I put in 1 L or 1 Q of water, the steam last for hours. Still I waited and waited for a suitable day. If I messed it up again like when I put the tint up, I would leave a lot of strange things on the windows and my kids won't want to ride in it.

But it was so darn easy. I should have watched the million view video. It is easier than that. I would think the DIY tints are easy. But I think his tint were professionally done. So I suppose all the glues are about the same.

My contribution: Open the car door widely and steam from an angle so all the steam goes out of the car. My steamer is professional grade. I use a pointed nozzle so it's all steamy even outdoors.

Open the window slightly and start steaming from the top. First, tape a plastic bag on the bottom of the window so water slides down onto the ground and not the door. Tape on the window so the tapes and the bag will go with the tint when it's removed.

My top edge is already peeling off so that's where I started. You may start from the corner if that comes out first, or like the guy in the video, make a cut in the middle so you have a corner of the tint to start with.

I point the steam from the top, aiming at the meeting point between the tint and the glass, while I pull the tint down. If you don't have a pointed nozzle, you may have to steam around the edge.

If the tint breaks up into two, you can carry on one side at a time. If the tint stays in one piece, you pull and steam at the same time one corner, then the other, then the middle. Pull gently all the time. If the tint is steamed enough, you will feel that it's easy to pull. And when you feel that it's harder and harder, steam more.

Never saw and had any problem with residue or glues.

It also depends on how the tint is installed. The instructions I got was to leave a lot of margins on the sides and the bottom. But that was killing my installation. I just couldn't get those margins into the sides and bottom of the window. And since I have an exact template of the window, I should have left a very thin margin. It's easy to go into the window frame and there will not be visible gaps.

Maybe next time I use static clint films.

Structure 1 : first structure in the universe built using EMT and straps

Brought to you by Lows Inovation Lab.

This is bunny's portable bathing tub. He uses the whole of our bath tub so he doesn't make everywhere wet. We still put this tub in our tub but water use is a lot less. There are plastic EMT caps at the legs to protect the tub.

You can probably stand on the quad-strap cross joints without slipping. Very strong.

You can combine 2-hole straps with 1-hole straps for tee joints, and hardware straps for rotation and sliding. You can use 2 1-hole straps for fixing conduits when it's not load bearing.

1-hole straps are quite neat when snapping onto conduits. Here I use it for holding aluminum wires for the cage.

This is totally built without measuring tools, other than that the EMT's are cut to size. The quad strap joints have a tendency to be perpendicular, but not exactly. I suggest to using #10 nuts and bolts so there is less wobbling of the straps and the joints will tend to be more perpendicular.

World exclusive: Crius Quad stripes for low cost custom furniture, building and construction

From the Real Lows Innovation Lab

Previously, you can build furniture using PVC pipes or rigid conduits. This is because the pipes can be joined by coupling and tees that fit together. Not so much for emt conduits.

It's a shame that emt is only about two dimes per ft. There are fittings but not designed to couple pipes together rigidly. Also, an elbow cost a few dollars. I am not aware of any tees.

One day I screw 4 EMT stripes together and put them around two EMT conduits at a cross. The rest is history. Contrary to intuition, the cross joint is as rigid as you get, even though the stripes are a little flexible. It is difficult to put the pipes in position even before the screws are tightened.

There is no movement in any direction. You can't even twist the pipes. I don't know how much load it can carry before slipping gradually over a long time. But I think you can support body weight with ease. And you can design around this possibility of slipping by using load distributing for example. And the load can be born by the length of the pipes instead of the joints, such as legs of a table.

The cost of each quad is about 5 dimes. Not too bad that is about twice of a PVC tee.

Imagine the possibilities! You can build anything from a small stool to a swing sofa in the yard. The joints are not as neat but it is much easier to design and build without the need for tees. It's much stronger too.

If you just need to fix two pipes in position without much load, you just need two one hole stripes instead of 4 two hole stripes.

I'm pretty surprised when I found out that my hardware store has an innovation lab online! I don't know how long they have it. But my impression is that they are trying to move away from hardware as soon as they can. The all important section is the appliances. Then anything connected to expensive remodeling.

A sq ft of flooring cost a few dollars. A can of paint can be over a hundred. They are just not interested to stock pipe fittings and emt fittings. Last year or the year before they ran out of EMT pipes around xmas, causing their competitor to mock them with the sign "always in stock" by the pipes. And for a long time the 25 pack of emt stripes are not restocked.

Once I was in the middle of a project in the midst of thanks giving. I ran into the store on black friday morning and caused a sensation. The guy in the pipe fitting section was very unhappy as if I jinxed their black friday. They had high hopes when I came in but I can hear him murmuring "stupid fittings".

I bet very few staff knows they have an innovation lab online.

Another great tip: you can sand the zinc coating with a sanding block (or paper) to give a brushed stainless steel finish! There's very little effort and the coating remains stainless. I bet it will take paint well too.

I discovered craft acrylic paint. They come in small bottles so you don't need to waste money or storage for a small job. They have all the colors, from pink to metallic copper. The brushes are truly washable with water. All are non-toxic with little or no voc. They are tough and some claim to be dishwasher safe ?! Some even use it outdoors and let it weather. You can also protect the color with some clear outer seal.

Successful Green Pea litter system for bunnies may be cats and other small animals

I gave up on the Green Pea system because it was difficult to clean thoroughly. But it was much worse when I went back to disposable litter. The pellets are gone from the pet store shelves. The remaining have some have sticky residues and made a mess with bunny's tail. I ended up on the top quality paper litter. It's expensive and still I have to change often to keep bunny dry and clean. Over $10 a week just isn't right.

From avoiding pollution during engine oil change, I got the idea of revolving cleanliness. Say you use the same used oil tray every time and you don't ever need to wash it clean with detergent. Say after cleaning some spills, the floor is cleaner than before and you don't normally go there, that's clean enough, until next time.

For my modified Green Pea system, you just need 3 trays that can stack close together, and some sort of screen as in screen doors. And the main ingredient is aquarium gravel. And you also need some duct tape.

The bottom tray is unmodified to hold liquid.

You drill a lot of small holes on the middle tray such that gravels rarely get through. These holes are to drain water after rinsing. The number isn't important but affects the speed of drainage. But the holes should be placed such that water do not pool on the corners, the sides or the middle. A little pooling also not important. Then you put 1 to 2 inch of aquarium gravel on this tray. They support the weight of the bunny and allow liquid to drain to the bottom.

For the top tray you cut off 1 to 2 inch off the bottom, a height approx equal to the thickness of the gravel. Replace the bottom with a screen. I use those for solar screen door. Tough, flexible and soft. I duct tape it to the outside of the tray. I tried to super glue it but not successful yet.

That's it. You need two to three sets for rotation.

For extra credit, if the stacked height is too high for baby or old bunnies, you can put off parts of the wall in all three layers to let them in and out easily. A shallow tray will do, one to two inches. But usually trays are deeper than that.

So, the bunny do it's business on top of the screen. It's weight is supported by the gravel. Any solid or pill will stay on top without going into the gravels making them difficult to clean. If some solid sticks to the screen, you can sprinkle some paper litter to keep clean. You can just lift the top tray off with the screen to empty it as often as you like. Liquid will go into the bottom of the gravel layer.

Bunnies like gravel. He likes to dig a shallow depression and rest in it. Pea gravel from hardware store will do but smaller ones should be more comfortable. I suggest white angular gravels from aquariums but not too fine. You can easily see how dirty the white gravels are. Angular ones stack as in paving well while round ones slip around the feet. Indeed he sleeps on the gravels a lot of times, more so with the soft clean screen on top.

To clean, solids are simply emptied from the top tray as often as you like. Each day you need to soak the screen tray on top of the bottom tray a bit. Then it's easy to rinse it clean of sticky solid with or without a moderate pressurized nozzle.

The gravels just need to be rinsed. You can pour out the top water and let the water drain from the bottom holes.

It's not easy to dry the gravels thoroughly. The sun dries fast but only the top that it sees. I tried to bake it in the oven. It would work but you need a big oven ware. The gravels also have to be relatively clean, free of pills, so that the smell reminds you of cooking rather than the bunny.

This setup is designed to dry the gravel in place. With or without the sun, the gravels at the top will dry fast. So three sets of gravels are enough for a rotation. After enough drying, you just put the gravel tray onto the bottom tray and put back to use. The gravels may not be completely dry, but the top layer is dry, drier and cleaner than the last batch that the bunny did his business the day before. In comparison, if the gravels are not completely dry in the oven, you will feel the wetness when you pour them around into the litter tray.

In my last version, my two problems are that too much water with dirt goes into the outdoor laundry sink. If I use it to irrigate, the pills are fly magnets.

This time I just use a small patch of gravel pit outdoors to clean and drain. Since the pills are separated and the gravels have relatively little dirt in it, I just pour the dirty water down the pit for irrigation. The gravels will help to trap the tiny dirt down there better than bare soil. Everybody and the plants are happy. The liquid waste I pour as far away from plants as possible. And with a lot of water to dilute, I hope the plants are OK with it.

The running cost is the very few gravels that are lost everyday, and water. The water consumption I would say is about a flush of the toilet. I think I can use a lot less water if I try. It's revolvingly clean as long as the gravels don't smell. The top gravels will be relatively clean.

For cats, you can't have the screen layer. The gravel lost will be greater when you scoop out the solids, but you can use cheaper hardware store gravels.

Small creatures like to live in the gravels. So you may want to dry the gravels high up on some stands. There are plenty ways to clean the gravels thoroughly once a while. Many germs die at 60 C for a minute or so. (please check). So pouring boiling water on the gravels and soak them until the water cools will do nicely to kill a lot of things. Bugs will do poorly than germs. You can also use chemicals like hydrogen peroxide, salt, baking soda, vinegar. Bartender's friend is a rather strong acid but organic. Just don't eat it or let it absorb into your skin too much.

Even if the duct tape isn't secure, they don't come off that easily during cleaning, and the whole setup is rather neat when stacked on top of each other. Let me know if you have ideas to get rid of the duct tapes.

Green Pee Litter Box II (for rabbits)

I gave up on the Green Pee system once. I figured out dry is the way to go and you can throw away the trash when and how much you want.

I tried different dry litter and finally back to square one, the high quality plain white paper litter, that expands 3X. I had been running away from it since day one. It's about the most expensive type commonly available. I tried most others. Now my bunny is a bit old to clean himself thoroughly so I have little choice.

The problem is, the litter box is so good that he sleeps in it too. And pee outside the box. And since he can't keep his feet dry outside the box, he pee inside the litter box too.

It's not lack of training or he is hard to train. When he was a baby he just pee on the tiny corner litter box. He kept going when he was a lot bigger, even when the box can barely allow him to sit down.

Now we just want to make it comfortable in every way, and now he lives indoor.

We just can't have his "cage" all covered with expensive litter. And how to clean it? He pees like a facuet.

So we went back to the Green Pee system and see what we can improve. Gravel is less messy if he pees and sleeps in the same place. And we can surely afford to cover the whole cage with gravel.

Now it looks like this. The litter box is two simplest cat litter box stacked together. The top one has some small holes at the bottom for drainage. The bottom hold any liquid passes from the top. The top litter box has inside it a layer of aquirum gravel, or substrate. On top of the gravel is a screen to reduce dirt or pills to get into the gravel. We use solar type screen for patio screen doors, which has a thick plastic coating on the screen wires.

Bunnies like gravel. Given the chance he will dig a shallow depression and hug his body in it. But earth and sand are similar. Just that gravel is easy to clean. Cool too.

My previous mistakes include thinking that the gravel must be completely dry before next use. For this 2nd version, the bottom box is taken away for the gravel to drain through the holes after rinsing. After overnight draining and an hour or two under the sun, the top gravel will be very dry and comfortable. Here we don't worry about humidity.  If the gravel isn't that deep, almost all will be dry except for some on the bottom.

Last time I used pea gravel from gardening stores. They are bigger and less comfortable to sleep on. The sizes of gravels vary a lot. Indeed I use a sieve to collect smaller gravel for the litter box.

Aqurium gravel or substrate are much finer. Some are not a lot bigger than a grain of sand. It's a lot more expensive than pea gravel but you don't need that much. About 10 lb for a litter box.

Some still wet gravel on the bottom doesn't matter, as long as you don't turn over the gravel. In version two, the gravel drains and drys in the litter box. Once done the litter box is put back for use plus the bottom box to hold any liquid. The gravels aren't moved once the top are dry.

Acquarium gravel seems to dry faster. Because it's finer, you don't need that much.

The other mistake is thinking that you need something to absorb the pee. The pee can stay on the bottom of the gravel, and held by the bottom box. So the system is very simple. But you need to clean up everyday, which is rather simple. You can also put something at the bottom to absort the pee, like kitchen towel and baking soda.

I thought cleaning was easy after soaking in some powerful solution overnight. It was the other way round. The more soak, the more is the time wasted for drying. And it is messy.

Now the cleaning is just take away the top screen. Rinse the gravel in the litter box. Pour away the floating dirt. Rinse the bottom box.

It's seems that the gravel are lighter so it's easy to rinse clean. And you don't need that much to be comfortable to sleep on and hold enough pee under.

The screen can be cleaned using thin jet patterns coming out of a garden hose.

I clean everyday and have two litter box system for rotation. I can have 3 if needed, less than $10 each.

The problem of washing is that rabbit poop is top fertilizer but attracts flies. So unless you have some sort of draining pit outdoor that flies cannot get to, you need to deal with the waste water. I have a big outdoor laundry tub and I can wash things in it.

Fault tolerant vacation automatic pet feeder

Finally, I made it. I went on vacation for a full week and my bunny survived. Though I have a pan and tilt cam watching if anything went wrong.

Those on the market are too expensive. And even if I get one I don't trust them. First, they have a single motor. Auger / screw types can jam. If the motor fails, all meals will fail.

I actually built a multiple meal automatic feeder for my dog. It was complete with a hacked digital timer, and low level logic chips like NAND gates. I did that because I always have about a week to design and build it. And it have to work. The problem is, the motors are too expensive, or I couldn't reliably mount them to "open doors". So I only tested it for a weekend or two before he rested in peace.

At the time I hardly know what is a servo. And after I came across it, I just didn't have time to learn the hardware and software of a controller to drive them. And how much 7 servos cost? I used the cheapest motors and they work fine. The problem is that it's hard to glue some latches to the bare motor axle without gears.

This time around it's different. Tiny servos like sg90 cost next to nothing. Arduino kits are cheap and you can do a lot of other things with it. You order it from Amazon and they came quick enough before I setoff for vacation. I hope it's plug-and-play as they claimed. But I saved some money by ordering from other sources. So it's not plug-and-play but I figured it out how to program it.

I'm sort of a hardware and software professional so the rest is easy. The software is supposed to be simple, just wake up everyday at the same time and turn on different motors. That's why I actually built one with discrete logic that could be more reliable, and worked first time. But I don't trust a cheap controller working outdoors. One power outage or interruption the controller can be trapped into non-operational states.

I was prepared to write and test complicated software so if power is stopped for an hour, the operation behaves as if time has been lost for an hour or two, not whole days and not skipping meals.

After more thinking than coding, I realized it's best to drive the Arduino with a digital or mechanical timer. When the Arduino has stable power, it only need to use one location to remember which motor to turn on. The software is real simple. I was preparing to work overnight to make something work reliably. With this simplicity, I just needed trivial modifications to the sample code. There's only a few "critical" lines so I can tested them thoroughly in no time and went to sleep before leaving early the next morning. So to fail the timer has to fail and the board hardware has to fail. They seldom do.

My designs has been for the servos to open something like a trap door under food, and so all the food fall down to a tray. And I have no time to make the custom containers.

What I did was building a see-saw with fat lolipop sticks, with a cup of food on one end and a servo arm on the other end. When the servo turns the cup will drop. Everything is made of fat lolipop sticks that you can find in craft shops, and school glue. They are a surprisingly fast and secure combinations. To guard against earthquick, bigger animals and an angry bunny shaking the pet house, there are little slip guards also made of strips from wooden sticks and the cups are stabilized by cup cake paper liners. The craft isn't too bad but I have to build ad-hoc guards and defences to defend against bigger wild animals and the weather.

Wooden sticks was a surprisingly good choice because you can stack them up with glue to your desired height, or stick them to square dowels, also from craft stores and also hardware stores.

All the wires from the servo, 21 of them, are not soldered, but using the wires from the kit that plug directly into the Arduino board, and also use the tiny development board for the 5V and GND distribution. It doesn't matter if the wires fail to contact. Only one servo will be affected by one circuit failure.

And to ensure a good drop, the first thing was to custom built a big tray and inclined walls for the pet house. I had sewing threads glued to the cups and sticks to ensure they fall as expected but not into the tray to confuse the bunny.

The see-saw isn't the best design but I picked it because I had no time for other things. A long see-saw can balance out a heavy cup if the servo is weak.

As seen in the picture, one of the cup didn't drop. But there's only treats in the cups. There are plenty of other pellet food and hay that the bunny doesn't eat that much unless he has to. The problem was that the little vertical slip guard wasn't vertical enough. So the see-saw stick was trapped. This was a known problem in one or two of the unique handmade mechanisms. I forced the little glued sticks sections apart until it was smoother for the see-saw stick to drop. But one of them revert to the bad position eventually.

I almost built a automatic flush toilet too using the Arduino with servos. But it's too risky first time so the flush was driven by the lawn sprinkler controller for now.