Friday, December 15, 2017

Developing Eddystones App In Android

Eddystone beacons is google's answer to Apple's Ibeacon. Both devices use BLE technology but differ in advertising protocols.

Ibeacons transmit a single frame wherein the Ibeacon identifier bytes is at the 8th and 9th byte of the frame. See picture below as seen on Ibeacon Detector app on android:

And a more detailed data structure of the frame is below:

In comparison, Eddystones transmit 3 frames which is like below:
As an evidence, if you use Ibeacon Detector App to detect the Eddystones, you will notice that the data packets received always changes that is because eddystones transmit 3 frames.

I have previously developed an android app to scan ibeacons (A Simple Ibeacon Scanner App in Android) and this app can be slightly modified to scan for eddystones as well by removing the validation that look for "0215" pattern in the frame and look for valid values to identify the frame type as described in the last picture.

A lot of people ask, why do we need eddystones since we already have ibeacons? The answer is obvious, eddystones is able to transmit more data than ibeacons. Ibeacon frame contain only the RSSI, UUID, Majo and Minor. The latter 3 is used to identify the ibeacon, while the eddystones frames contain the TX power, Temperature, URL, Battery Charge Level, Instance Id, Namespace Id, and many more.

Monday, November 20, 2017

I repaired my Micro M3d Printer

It was more than a year ago when I bought my very first 3d printer to try if the technology really works as I have seen on youtube. During that time, it was the cheapest 3d printer available(not the diy type).

During the first few days, I had very good experience with it, no wastage, all printed objects were perfect. Then when I decided to print a chopping board that would take 34hours to print and left it printing while I went to work. When I came back in the afternoon, to my surprise and dismay, it failed and it continued to print but no filament is coming out. That is weird. All the happy days with the printer became a constant nightmarish struggle just to succeed in printing. It even came to a point where the heating element was destroyed and negotiated with M3D to repair it but they came up with having the entire unit be replaced with a new one, but the new replacement had also the same problem. That was really weird.

I got fed up and decided not to use it anymore and that when I will have a time to go over it again, I had to tear it apart to check what controller they used. Not until last Sunday when I decided to repair it. I first downloaded the latest version of the software and during the first run, it asked me to update the firmware, so I updated the firmware and try to print the wheel used in a mars rover. To my surprised, the printer output was fairly solid, this is the first good output it ever produced so I thought maybe there is nothing wrong with the hardware, it was just the firmware that made all that troubles.

I thought that was the end of the problem, but when I tried to print the same object, the x-axis slowly shifted to the right. I tried other settings but yielded the same result. It was not brittle but the x-axis keeps on shifting to the right, weird!

I concluded that it is not the hardware that is making all these mess, it was the software and the firmware. So I tried to look for alternative to use other software and I succeeded, Adafruit had an article wherein they used raspberry pi and octopi. I tried it, and so far, I am getting good result. Octopi uses Cura engine which is used by Ultimaker.

So far this is the 3d printer busy printing the mars rover wheel:

Another good thing about using octopi is that I dont have to connect my laptop to the rpi all the time so while the rpi is busy printing i could use my laptop developing the accounring software and play dota.

Tuesday, October 3, 2017

Spindle Upgrade Project

The spindle that came with the cnc I just got is small, good enough to cut even a 12mm thick acrylic which is awesome because laser cutters requires 100w to cut acrylic this thick. But for me it is not powerful enough because I am planning to use the cnc as production machine for my air purifiers si I need to upgrade it and I found a suitable dremel class hand tool which can be bought cheaply at local hardware.

It is perfect since the tip of the hand tool is threaded so that means I can create a custom bracket having the same diameter as the original spindle and I will attach it to the cnc with no problem.

So I had to buy aluminum block (50mmx50mmx50mm) and off I go to my favorite machine shop to have it done perfectly. And with a few discussions with the machinist, he was able to execute the task perfectly and here is the result:

but when I tried to tighten the clamp to its maximum, the spindle still moves but I don't blame the machinist since I was the one who said the diameter should 45mm, but I was able to solve easily by wrapping the bracket with scatch tape and the problem was solved:
SO I test it further while moving the z-axis upwards, it wont go up to 30mm because the custom bracket was too thick it acts as a barrier so, tomorrow I will go back to have it fixed, it was still my fault, hehe here is the problem area:
Another problem I encountered is that as the rotation speed reaches 12000 rpm, the attached endmill begins to wiggle so I still need to fix it:

Monday, September 25, 2017

I got a new CNC and I made a simple spindle dust hood

I have bought a mini desktop CNC. I need this CNC because I have sold the big cnc I had and planning to put an air purifier business but to make 1 air purifier, I would need a casing and to make a casing, I need laser cutting services which is very expensive so if I have my own small cnc, I could bring the price so low that I could beat the branded air purifiers not just in terms of very effective air cleaning but the pricing as well.

Ok, that solves my problem, and yes it can cut acrylic, but to use it, requires devices and add-ons to protect the cnc itself and prevent dust from flying all over my tiny place, that's why I came up with the idea of creating at least a dust hood for the spindle.

All the dusts and forces that makes the scatter and fly over the place is at the spindle, so having a dust hood at this area of cnc can help solve the problem by 90 to 100% .

Here is the cnc with my old raspberry pi 2:

My original plan was to use the cnc with the raspberry pi 2 and make a casing similar to this:

but the raspberry pi was very slow in transmitting gcode to the cnc so I scrapped the idea.

I started the project(making a dust hood for the spindle) last Sunday, and I was able successfully created a simple dust hood which is like below:

It passed all my tests, it can prevent dusts from flying and scattering all over the place. Efficiency is at 85% but installing and uninstalling is not easy and very inconvenient, so I separated the attachment and brush holder and went to a nearby machine to have them tapped and the result was awesome but very expensive. The machinist charged me Php800 but I haggled until we agreed at Ph600 which is still very expensive.

Here is the much closer look the new dust hood:

Saturday, September 16, 2017

New Air Purifier Designs and with Extensions

It has been over a month since my last post and during that span of time, I have made several iterations in the design and I even made an industrial class version but it failed because I am trying to copy what others are doing(currently available air purifiers in the market). But I will tell the reason why it failed at last part of this post.

The iterations I made so far and it seems the final version already is that I made it smaller, I used lower powered but bigger cpu fan. I like the bigger fan because it has bigger blades and with bigger blades, it can suck in air more easily on a wider area, I sacrificed the higher power to get rid of the noise. And the last revision I made is to glue all parts except the door for changing the filters and removing the bag of activated carbon. I also got rid of using multi-filters because those unnecessary filters were useless, I found this out during my testing of the industrial grade air filter I made. So now, I only use hepa filters. These filters can remove particulates in the air even those PM2.5 class particulates where harmful chemicals and air borne viruses and bacteria belongs.

I also added a third motor which can be detached from the fan when not needed. This third motor will allow the air purifier to catch more air as far as 3 meters so that means the space that it can help clean was widened from a mere 18sqm to about 25-30sqm.

Here is the new air purifier:

Here is the extension module:
Here is the industrial grade air purifier:

The design failed because of only 1 reason: it does not have enough activated carbon in it and most of the air wont pass through the activated carbon. It is also very expensive.

My original design was very effective at removing air particulates and odors because the air has to go through a very thick layer of activated carbon which is about 50mm thick and there is a chamber where the air goes and will not have a choice but to go up and pass through the activated carbon.

Saturday, July 29, 2017

My Air Purifier just got a second motor

I could not just wait for the air to come into my air purifier just to be cleaned. I needed a way to somehow force the surrounding air to be pushed inside it to be cleaned. So the only option I had in mind is to add a second motor to suck in the air. And here it is:

With this design however, my air purifier is no longer cheap because the materials I used for the casing has been doubled, 1 motor and 2 extra brackets plus the top cover not to mention, I already use 100% activated carbon because it is really 5x more efficient than ordinary charcoal.

Here is the actual result of my design:

I also noticed that the air being sucked in may not penetrate the inner portion of the activated carbon inside the eco bag, so I customized the bag itself to have a hole at the center located in front of the motor that sucks in the air. Which is like the one shown below:

So in this case, the air will not just go around the bag but will be pushed inwards at the center of the bag living no choice but the air will be pushed right into the activated carbon.

And here is the actual device itself:

My testing shows that as I blow smoke directly into it, 90% of the smoke gets sucked in immediately which is an indication that air cleaning is very efficient.

Future plans:
I am thinking of adding another chamber as the final stage air cleaning but that depends on the performance of the device, for now, I am so happy with the result because it is very efficient.

Saturday, July 22, 2017

Adding Air Filter to my Air Purifier Project

I was too busy this weekend to pay attention to my supposed Wall D├ęcor Weekend Project, and instead, my attention is focused on adding an air filter to my air purifier diy.

I have spent several days searching for a reliable seller of air filters and inquired at leading industrial suppliers, but as it turned out, these industrial suppliers are also manufacturers of industrial grade air filters so they snub small time buyers like me. But assuming they grant my wish to buy small piece of their product, still they insist to custom build the air filter with frames and their minimum thickness is about 1" which is too much for a small air purifier like what I did. But yes, I really like the HEPA air filter they are selling because it is the world's most efficient air filter.

I haven't gave up on them yet, coz I'm so crazy about their HEPA air filter, but it is nice to have, but with the kind of supplier, well, oh well, I am still hoping that I could find one and instead I ended up with air condition air filter. It is a 3M brand called "Filtrete" .

One particular feature of this product is it cleans the air and very efficiently because it used electrostatic fibers which act like magnets to trap dust, bacteria, dust mite, and many harmful dust particles. Here's the actual air filter:
The package recommend just one layer but I used 2 layers. SO that makes 4 layers of air filters inside my air purifier. Why 4 layers?

4 layers because I used eco bag to wrap the charcoals and activated carbon so that makes it 2, then I added 2 layers of Filtrete so that makes it 4: