DIY Homemade pool water solar preheating system - by Jordi

Economic system of heating pool water

This past summer Jordi from Valencia was consulting on how to heat the pool water with economic polyethylene tube, and discussing their results, and is happy to share it with you.

Surely he noticed this post (system that does not use nearly as efficient) and was encouraged to heat his pool that way, and wanted to "removing the cold", raising its temperature from 18 to 25, a more comfortable temperature, taking advantage of the close roof surface where the sun hits well.

Jordi told me that he would use PE pipe Ø20 mm. and had doubts if it would work; the pool is quite large , 14x3 meters. I had thought to extend about 250 meters tube had calculated that fit on the roof.

Lighting by electromagnetic induction: Current best choice for high power lamps

When it is necessary to illuminate a street, building, etc, and lots of light output is required, induction lamps are more profitable than the LED because of its lower price and its durability.

Campana 250W used in warehouse

Key Features:

Connecting an IDE (DVD-ROM, HD, etc) unit to a motherboard without IDE port (SATAS only)

Using an IDE-USB adapter we could "recycle" the IDE recorder

In many current motherboards like Gigabyte GA-F2A55M-DS2, no longer include IDE ports , which have been displaced for speed and economy by SATA. 
But if we have such an old IDE DVD Burner 3.5" and we want to continue using it (it is not the time to pull something that works), we can be forced to pay more for a motherboard with those ports, or instead we can place a IDE to USB adapter that functionality allowing us permanently for 4 € (saving us 30 € that costs a new DVD recorder).

As we saw in a previous post , adapters SATA / IDE to USB are very practical; it specifically has to IDE 3.5 "and 2.5" SATA port, very useful when you need to connect hard drives without opening the computer:

You can buy on Ebay from 3.99 shipping included in Spain

We just need build or search for a USB connector on motherboard, which I believe to be the most difficult part (although you can use a box of a PC to go to waste); I for example have obtained one cutting the Firewire 1394 connections (in the first picture the gray cables cut) not be used for anything, and solder the red, white, green and black USB adapter cable at positions corresponding to leave permanently connected to the motherboard:

In the picture below, the adapter connected and working, although I had to remove a lateral from the connector for the power supply on the left:

Computer with dropbox slows: Usage Tips

I recently repaired a computer that "slowed down" a lot to boot. It was a laptop with Celeron, quite outdated already. What was my surprise that the cause that produced this problem was they had shared a folder several gigabytes of information in Dropbox  (videos and photos on vacation)  and not a virus; the users wanted to backup everything in the cloud, so that every time Dropbox was checking changes, the hard drive was "going crazy".

The plotter fails to recognize the cartridge: Repairing a 500-800 HP Designjet 42 "

We had a problem with our plotter; it marked "unrecognized cartridge" error before finishing of each printed plan; when we repositioned the cartridge the problem was solved for a while, but it seemed a problem of poor contact with the cartridge chip (it was produced when the motor axis ink supply was activated).

To repair it, you have to access the module cartridges; first of all we need to remove the cover of Control, it is a matter of finding and removing all the screws, simple task and which information is on the internet, so that I refrain from commenting;)

Turn off RadioCD in a Xsara Picasso car: Connection to the burner

We dropped the front screws and side to find the lighter wiring

RadioCD included by factory in the Citroen Xsara Picasso does not disconnected immediately after removing the key, so remains on a couple of minutes after the unit is disconnected.

In this case it is advisable to connect the red wire RadioCD "ON" (not the one going to the battery, but the activator) to positive cable of the burner, and then this hassle is avoided.

In Depth: Lexman 9W LED bulb E27 230V 4000K 806 lm of Leroy Merlin

In my case gets 3 years warranty

LED bulbs are already flooding the domestic market, with options for almost every need.

We will analyze in detail a model that sells E27 Leroy Merlin with 3 years warranty brand Lexman  (non-publicizing, just to compare).

This bulb shines very well, with a more than acceptable theoretical efficiency of  90 lumens/W, perfect for replacing incandescent bulbs of 100W  (tested). 

His tone, a clear yellowish 4000º Kelvin, is suitable for everywhere in the house (although it is away from 5600K natural sunlight, colder), and a higher CRI of 80, enough.

If we break the glass we see that the controller gives 94V, feeding 33 LEDS 3528 series (which theoretically receive 2,84V and 0,27W each emitting 24 lm / ud), giving 806 lumens and 9W according to manufacturer (and although I can not measure it, seems to be true from its luminance):

The design to dissipate heat is of lightweight aluminum inside, which contacts the exterior part thermal plastic, that transfer worse the heat than aluminum, so it does not burn and can be touched, but it would be best if it were metal body such as lamps from Ikea, since the chip area after 6 minutes is at 43 ° C with 18ºC environment temp.:

With the (+ - 1 ° C) temperature sensor check infrared LEDs

and reaching 64 ° C! after half an hour, a temperature not very convenient for semiconductors. The manufacturer indicates a lifespan of 15,000 hours, but I hardly trust it, I recommend saving the invoice and not buying this bulbs because, if we use a lot, It will not reach the three years guaranteed!

Anyway, for € 6 per bulb, and for environments such as the bathroom where they are at most one hour on, they are more than recommended. For other uses, best to get better quality lamps.

Preparing a ventilated protective mask for Airsoft

Homemade ventilation mask

Eye protection is mandatory in airsoft, but most masks do not have enough ventilation, so you end up with very low vision by condensation on the policarbonate plastic.

As others have done before me, the trick is to introduce fresh air with a small fan and battery; I used a fan from a notebook computer, with a small switch and a 18650 lithium battery (4.2V) in the corresponding adapter .

Repairing an old Mitutoyo profilometer probe

Some time ago I repaired an old Mitutoyo profilometer 178-928D , which no longer has spares and which had broken the pin that transmits motion to the head holder; a calibrated shaft that moves left and right and which I hold in the following image (the pin / screw was in the center hole):

This probe has a very simple operation. The spindle that is coupled detects changes in a very similar way that is translated the marks in an old LP music disk, transmiting the movements caused by the roughness by a magnet and coil needle.

The shaft that moves the spindle is moved in a controlled manner with a step by step motor to an endless spindle, first the engine slowly forward in the measurement phase, and then quickly picking head to its starting position, all controlled from the profilometer which is connected with a cable with 6 wires (that is a seven or eight cable, but one or two are not used, as you can see in the following images after repairing the cable too):

Repairing a tape backup LTO 2 unit: HP Ultrium 448 with broken tape

In a unit Ultrium Fujitsu (HP) for backup, the tape had broken, being useless as the mechanism for capturing the tape was inside it. To repair the unit is complicated, recommended only to those who have already dealt above with similar mechanisms (VHS, glory times). 
To repair it is necessary to understand the method these units use (and many other models are based on the same principle), a curious way to save space by having a single drum in the cartridge and in the unit, where the tape passes from one side to another as information is stored, until it ends.

These LTO (Linear Tape Open) are optimized for capacity, and the latest versions, able to store 2.5TB of information in one cartridge that costs about 20 €, making it very competitive in terms of price and space currently.

After this brief introduction, let's go to the subject.