Dual-phone method for self hair cutting

Of all the youtube videos, I still couldn't find one that uses smartphones as a back side mirror. If you do not do this, you do not have a full straight backside view of your haircut. Without this view, many cuts are not feasible.

The good thing about the dual-phone method is that it's free; you just need to find two phones to use for the duration of your hair cut. Tape one to the wall or bathtub tile with the back camera facing out. Use the other like a handheld mirror.

The apps to use are two-way video chats like facetime, hangout or skype, in which you just need one side of it. What I actually use is IPCam to turn the phone on the wall into a webcam. On the handheld, I use Tinycam for the display. They work together and both free.

The alternative is a hinged three-piece mirror found on youtube, costing a silly amount of money. Of course, you can do it yourself but phones cost nothing and you need to do almost nothing. Of the 3 pieces of mirror, you only need the two side mirrors. They cannot be too small that you have to get very close with a limited view. With a smartphone cam, you can see at any angle you like. For Tinycam, if you double tap the screen, the image will zoom into the point of contact.

You do need two decent phones with decent wifi connections or else there will be a lag between the actions and the image on the handheld phone. Though it's not a big deal if you only want to see the result after some cutting.

I tried something similar many years ago. I used an old camcorder as the back camera, attached to a portable DVD player with video input. It sort of worked but you really need a tall tripod to mount the camcorder. It's a bit of trouble to hold the screen and you can knock out the whole system anytime. It's not possible to do it in the bathtub, my favourite place for the ease of cleaning.

I forget all about it because I developed my way of self-hair-cutting and has been using it for a couple of years now. First, you need Flowbee since it is what hair stylists do for the most part. Then, you need a Philips trimmer designed for self-hair-cutting.

The Flowbee allows you to cut all your hair to the same length, without which you have to do it approximately with two hands, having to mount or hang the handheld screen onto somewhere convenient. Some new stylists have trick clips to do it more precisely; you can do it blind with the clips. Flowbee is for short hairs from a quarter of an inch to several inches, more suitable for men. Though, it's as clumsy as a dinasour when the vacuum is attached.

The trimmer head of the Philips can be rotated at any angle, so you don't need to twist your arms to trim your back hair. It has all the attachments so you can fade and blend if you know how to. It has been a couple of years now and still works like new.

My tip to get a straight horizontal endge at the back is to use a strip of velco, the tough side, wrapping half the head at the back, attaching to a rubber band to wrap around the head from the front. Wear the velco band from the top of your head. Slip the band down to the hairline where you want to cut and then use the trimmer.

Scheduled blocking of websites using cheap routers

Searching for how to block Facebook on a schedule, you can see how complicated it is. Actually, just blocking a site like this is complicated by itself because of the many IP's it could use.

You may want to block youtube, gaming and social time-wasting websites, but allow two hours of access in the evenings every day. The amount of IP's to deal with is phenomenal. Also, nowadays many sites use the https protocol so URL-based blocking won't work. Somebody set up a proxy server on an old laptop to filter the web contents, but both the installation and maintenance are troublesome.

I find the DNS based solution very simple. In DD-WRT, a line in the /tmp/hosts file can block the whole site:

10.0.0.1  www.youtube.com

where a non-reachable IP is assigned to the external website. So you just need two versions of the hosts file, and restart the DNS service dnsmasq after the file is changed. Then you need two scripts as cronjobs, for example:

0   22   *   *   *   root  sh /tmp/stop.sh
0   20  *   *   1-4  root sh /tmp/go.sh
0  19  *  *  0,5,6 root sh /tmp/go.sh

At 22:00 every day, youtube and others sites are blocked. On weekdays except  for Friday, movie time starts at 20:00, but earlier on other days at 19:00. The schedule can be entered via GUI on the Administration > Management > Cron box.

The "root" prefix is the one thing that I hate developing anything for dd-wrt. Cookbook instructions are good enough for me. You need that to run the commands with root privilege, or it wouldn't work. Because of its limitations, it mostly does something different from Linux, even though the source codes have the same origin. There are full of landmines like this and the system can never be documented enough. Even if there are documents, the functions may not work on your build version because of different chipsets and manufacturers.

To modify the hosts files and 3-line scripts, save a startup script at the Administrations > Commands tab:

cp /tmp/hosts /tmp/hosts.go
echo "10.0.0.1   www.youtube.com">>/tmp/hosts
cp /tmp/hosts /tmp/hosts.stop
echo "cp /tmp/hosts.go /tmp/hosts"> /tmp/go.sh
echo "stopservice dnsmasq" >> /tmp/go.sh
echo "startservice dnsmasq" >> /tmp/go.sh
echo "cp /tmp/hosts.stop /tmp/hosts" > /tmp/stop.sh
echo "stopservice dnsmasq" >> /tmp/stop.sh
echo "startservice dnsmasq" >> /tmp/stop.sh

Basically, it's adding one line per website on the hosts file to be blocked.

The blocking is not necessarily immediate because of the browser cache. My observation shows that the cache expires in a few minutes at most. That means if you have been watching youtube movies less than a few minutes when the blocking starts, you may still be able to access youtube for a few more minutes. Once you stop accessing youtube for a few minutes, you cannot access it again during blockage hours. I doubt if that makes a loophole. But this can easily be plugged by enforcing a total internet ban for a few minutes, for only those IP's assigned to kids.

Now, the blockage affects everybody using the router as the DNS nameserver. For adults, you can use public servers such as the google ones at 8.8.8.8. You have to do it on every adult machine. For the kids' machines, you can use the DD-WRT access restrictions to block port 53, so all DNS requests are rejected if they try to hack, forcing the default name server 192.168.1.1 to be used. To select the affected machines, only the IP range works on my version of DD-WRT.

MAC-based restrictions mostly don't work on my version. So I have to use Static Leases on the Services tab to assign IP's to machines by their MAC's. It should be noted that it is rather easy to change IP's on any machine to defeat blocking. A simple solution will be a script to police the lease table at regular intervals and send me an email if the same MAC has other IP's assigned. It would be rather painful to develop on the router but a lot less hassle using an old laptop with Linux installed.

I also use OpenDNS for the underlying web filter. It's about the only DNS filter that allows you to customize categories to block, to whitelist and blacklist. For example, I disable all search engines but whitelist Google. So I can concentrate on getting the SafeSearch mode working on Google. The same way I disable all video sharing sites but whitelist youtube, so I can concentrate on making the restricted mode work. The router is setup to allow these sites through. Once they are working fine, I can block each site with a line in the hosts file.

The other interesting approach I tried is to install a parallel DNS nameserver on an old laptop with Linux installed, on the same wifi network. It is trivial to install Dnsmasq and works in no time. You just need to point to that machine IP for the DNS nameserver. It's the same Dnsmasq on DD-WRT but on a more powerful machine, with lots of memory and hard disc space. More fancy things can be done but the blocking above can be done by two static hosts files, one on the router and one on the Linux machine. You just need to change the nameserver file at the router, for the request to either go straight to OpenDNS or via the Dnsmasq at the laptop. But you have to make sure that the hard drive is not constantly used. The /tmp directory in dd-wrt is a RAM drive.

0 22  *  *  *  sh /tmp/stop.sh
0 20 * * 1,2,3,4  sh /tmp/go.sh
0 19 * * 0,5,6 sh /tmp/go.sh

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.