This might also be interesting for you: Do it yourself powerbank with voltage regulator and voltmeter

List of components

To demonstrate the function, I have decided on a small test setup. I need the following for my test setup:

• Barrel jack 5,5 x 2,1 (1.0.1)
• Voltmeter (1.0.2)
• 5V power supply unit (1.0.3)
• Barrel jack holder (1.0.4)
• Barrel jack Bridge(1.0.5)
• Some cables (1.0.6)

Assembly instructions for bracket and bridge

The first step is to print the holder (1.0.4) and the bridge (1.0.5) with the 3D printer. After cleaning the printed parts, I cut two M2 threads into the holder (see 2.0.1). If you prefer to work with self-tapping screws, you can skip this step. The barrel jack is then pushed into the large hole in the bridge (2.0.2) and screwed tight with the nut on the front of the bridge (2.0.3). Fitting the bridge to the bracket is also very simple: Slide the bridge with the recesses on the right and left over the two cylinder surfaces on the bracket (2.0.4) and secure it with M2 screws (2.0.5). The bracket and bridge with the barrel jack fitted form a very stable unit that can absorb large forces. If everything is fitted correctly, the barrel jack should not protrude, but should be recessed by 0.3 to 0.5 mm.

Wiring and soldering the barrel jack

Now we come to the core of this article: wiring and soldering the barrel jack. I use pre-assembled plugs and sockets that already contain crimped cables and a strain relief. The colour coding of the cables is also practical, as red stands for plus and black for minus (3.0.1).

The barrel jack with switching function usually has three solder lugs. The negative pole is always switched, i.e. in figure 3.0.2 this corresponds to number two. The negative pole of the primary power supply, e.g. battery or accumulator, is also soldered on here. Solder lug number one is intended for the common positive terminal; all positive connections are soldered here. The negative pole to the consumers in the device is soldered to soldering lug number three. Figure 3.0.3 shows the complete soldering of the barrel jack.

Assembly and connection

After successful soldering, you can now continue with the rest of the test setup. Firstly, the holder with the soldered barrel jack is screwed onto a wooden plate (4.0.1). The two mini-voltmeters are then attached to the wooden plate (4.0.2). The mini voltmeters are a creation of Nerd Corner. If you are interested in such housings, you can read the corresponding article and download the STL files at the following link.

Now I connect the cables soldered to the barrel jack to the mini-voltmeters (see Figure 4.0.2, pink frame). Next, I connect the primary power source to my 5V power supply and switch it on (see Figure 4.0.3, yellow frame). After switching on the power supply, a voltage is present at both mini voltmeters: 5.35 volts at the supply (red circle) and 5.28 volts at the load (green circle).

Integration of the second power source

As the current flows cleanly via the barrel jack to the consumer, the second power source now comes into play. I operate this with 12 V in order to have a clear difference to the primary power supply. Figure 4.1.1 shows the second power supply with 12.2 volts (turquoise frame).

Now I plug the second power supply with 12 volts into the barrel jack (Figure 4.1.2, blue frame). After a short delay, the value on the consumer’s mini-voltmeter changes to 12 volts (green frame). Nothing has changed on the primary power supply; it remains plugged in and switched on (red frame). The value is still 5.34 volts, which is 0.01 volts lower than before the second power supply was plugged in, but this is due to the fluctuations of the 5V power supply.

As a final step, I remove the 5 volt power supply unit from the primary circuit to check whether there really is no voltage on the primary circuit. Figure 4.2.1 in the yellow frame remains dark and so the test was successful!

Files for Downloading

• Barrel jack holder and bridge

The post Using a barrel jack as a switch appeared first on Nerd Corner.

To organise the workshop, I have developed a storage box for CR2032 and similar batteries of this type. There are already a few, but they all had the same shortcoming. The battery containers for CR2032 must always be opened with the proper side facing upwards, otherwise everything falls onto the floor. My battery cases for the CR2032 offer safe and clean storage without the cells falling out. In addition, you always have an overview of the number of batteries present.

The container is available in 2 versions, one for 10 and one for 22 button cells. The container consists of a drawer and a cover (container) and is safe against shocks and falls. The batteries are simply clicked into place and hold firmly in their drawer.

You might also be interested in: 3D printed Dupont connector

Construction of battery container CR2032

The container must be stable and durable, but still have handy dimensions. In addition, each individual battery must sit firmly in its compartment and yet be easy to remove. I also asked myself how many batteries the battery container for the 2032 should actually contain. Most sets consist of 5, 6, 8 or 10, sometimes even 20. In any case, the container had to fit in my desk drawer. As I was not sure about the number of batteries to be stored, I decided on two variants, one with 10 pieces and one with 22 pieces.

The construction on the CAD starts with the drawer, i.e. the slide-in part, the long part for 22 pieces. The width of the drawer depends of course on the width of the battery, the battery is 3mm thick, 2.95mm to be exact, and needs enough air between the individual walls. A gap of 0.15-0.2mm for each side is enough to avoid friction. So if we add it all up, we get a shaft width of 3.3-3.4mm. We create the holding force that prevents the battery from falling out of the shaft with the edge trick. We create a circular pocket in the centre of the slot with a larger diameter than the battery. Then we cut off about 1 to 3 mm of the material above the centre point, thus creating an edge. This edge must be slightly smaller in absolute length than the diameter of the battery (in this case smaller than 20mm). If you now push the battery into the shaft, it must overcome the edge, which is also possible due to the elasticity of the material.

Now the battery sits in the shaft and cannot overcome the edge in the other direction with its own weight. This principle is actually quite simple, with the necessary knowledge about material, manufacturing tolerances, forces and holding torques. In the end, it was a mixture of experience and a few test prints until the optimum result was achieved. Now the battery fits neatly into the shaft and holds perfectly. And with gentle pressure, the battery can also be removed from the shaft again.

The next goal was to design the slot so that it holds securely in the case. This is also an interaction of material elasticity and the right diameter at the collar that holds the construction together. After a few test pressings, I was satisfied.

The shell of the CR2032 battery container is quickly constructed. Basically, it is a cylinder with a base. The inner diameter was adapted to the insertion size to ensure locking and the hole in the bottom of the sleeve is for air release, because when the insertion is pushed into the sleeve, the air must be able to escape.

Files for download

• Battery container CR2032

The post 3D printed battery container for CR2032 appeared first on Nerd Corner.

You might also be interested in: DIY Powerbank with the Battery Shield V3 and Lipo Battery 18650

List of components:

• 2 x Hollow socket 5.5 x 2.1
• 1 x Battery Shield V3
• 1 x LiPo 18650 3500mAh
• 1 x rocker switch 250V/3A mounting dimension 15×10,5mm
• 4 x hexagon socket head screws M2 x6
• 6 x raised countersunk head screws M2 x 12
• 1 x module XL6009
• 1 x Mini voltmeter DSN – DVM – 368
• 7 x jumper cable

Implementation

Basically, the XL6009 differs from the LM2587S only in terms of current. The XL6009 provides an output voltage of 5V-35V and an input voltage of 3V-32V at 2.5A output current. To operate at 3A output current the XL6009 must be cooled with a heatsink. My choice fell primarily due to the small dimensions and the low price on this module. Since the capacity of the LiPi battery is limited, there is no need to install a too large step-up.

Construction

The Battery shield V3 has already been analyzed in detail here. Therefore we can start directly with the construction of the case. The case of the last powerbank is used as a basis, because the mount for the Battery shield V3 is already included. Now the two hollow sockets, the XL6009 and the mini voltmeter have to be integrated. There seems to be enough space for the hollow socket at the XL6009 output to be placed vertically above the USB Micro input.

For this project only the height of the case has to be increased. The raise also helps to fix the second hollow socket in the lid at the front. The position of the hollow socket with a mounting bridge is placed vertically as well. The hollow bushing for the XL6009 output is screwed from the outside. The hollow socket for the 3V output from the inside. This is important because two different hollow socket mounting bridges are needed. For a better overview the following illustration is provided:

I have added a new mounting part for the XL6009 module. It is a holder that is attached to the inner wall of the case. So the module can be screwed tightly from the outside. A disadvantage is the fact that the holder with module covers the LiPo and when changing the LiPo battery, the step-up must be removed at first. Ideally, though, the battery is rarely changed.

The lid was raised a bit compared to the simple powerbank and one or two crossbars were removed. This created space for the mini voltmeter. To be able to adjust the XL6009 without removing the lid, another hole was needed in the lid.

To set the hole as ideal as possible, it helps to assemble the case physically at first. So you can move the position of the XL6009 module on the mount a bit because the module has a 3mm hole and the mounting screws with M2 leave a little space.

To be able to turn the XL6009 on and off, a switch was still necessary. Here I opted for an ordinary toggle switch. Overall, I am satisfied, because the housing has increased by only 12mm compared to the other powerbank and the dimensions in width and length have remained the same.

Step by step assembly

Purpose of the powerbank

The powerbank obviously can charge smartphones and headsets via the USB A, just like any other powerbank. The 3V output can be used to power common flashlights or electronic modules. In addition, the adjustable voltage output can cover a range from 6V to 30V. There are many devices which are operated with 6V, 9V and 12V e.g. LED, radio etc..

I have specified the top voltage value up to 30V, but the XL6009 module could at least handle 35V. However, the mini voltmeter that I use is only specified up to 30V. Another reason is the Battery Shield V3 itself. For the Shield, the output is described as 5V and 3A, but the reality is lower than that. The reason is the internal voltage converter which brings the LiPo voltage to 5V.

The following table contains measured values that show the relationship (without internal voltage converter) between the increase of the ampere value at the input and the voltage value at the output:

One should not forget that with battery-powered voltage converters, the voltage drop during discharge is also a factor. In order to be on the safe side, I have installed a pico fuse with 2A in this powerbank. Attached is a table with ampere values that should not be exceeded by the consumer at the specified voltage:

Download Files

• Housing for the powerbank with the XL6009
• Housing for the powerbank LM2596

The post DIY powerbank with voltage regulator and voltmeter appeared first on Nerd Corner.

The flashlight was hard to position properly and it dazzled. For this reason, I came up with the idea of developing my own glare-free lamp, which you can simply place on the heating bed and is not blinding. Preferably wireless with a powerbank. I had already built my own powerbank with the Battery Shield V3, which I used as a basis this time.

This might also be interesting for you: Own powerbank with the Battery Shield V3

List of components

• 1 x Hollow socket 5,5×2,1
• 1 x Battery Shield V3
• 1 x LiPo 18650 3500mAh
• 1 x rocker switch 250V/3A mounting dimension 15×10,5mm
• 4 x hexagon socket head screws M2 x6
• 6 x raised countersunk head screws M2 x 20
• 17 x 5V SMD2835 LED strips
• 5 x jumper cable

Choice of LED

Since the basic housing of the powerbank with the Battery shield V3 was already finished, I mainly had to think about the lighting. LEDs with 5V or 3V should be used as illuminants, because the Battery shield V3 provides either 5V or 3V. For my purposes a lower lumen value is sufficient. After a short research I found suitable LED strips.

The light temperature of my LED strip is 6500K also called cold white. This light contains a lot of blue, which makes it easy to work with and details become visible quickly. Since the Battery shield V3 has three additional 5V and one USB A output, powering the LEDs is no problem.

The LEDs for the glare-free lamp are SMD2835. These are 2.5 mm wide and 3.5 mm long and have a slightly lower luminosity than a SMD5050. How much the LEDs consume is critical to the lamp’s burn time, as the power supply from the battery is limited.

Construction of the cover and middle cover

As already mentioned in the previous section, the base case of the powerbank is not changed. Instead, the LEDs are glued onto an inner cover. The middle cover also serves as a support for the hollow socket for the 3V output. Furthermore, a breakthrough was contructed to pass through the cables from the on-off switch. The slanted openings of the intermediate cover should help to apply adhesive to the LED strips from behind if necessary.

For the top side (the lid, where the light shines through) it became a little more complex. On the one hand, enough light should shine through, but on the other hand, it must not dazzle! Of course, a crystal clear lid would be ideal for the light yield, but as I said, then it would possibly dazzle. To strike a balance between effective light output and freedom from glare, several factors must be taken into account:

• Material selection (filament)
• Distance to the light source
• Thickness of the lens
• Printing strategy

The choice of material for the anti-glare lamp was “ivory”. The distance to the illuminant is 10.5 mm and the layer thickness (material thickness) is 1 mm. The layer height is 0.25 mm, i.e. one millimeter results in four layers, with the first layer applied 45° to the left and the second layer 45° to the right. Due to the different directions of the layers, the light is refracted again and again and becomes glare-free. This is a subjective perception and the designation glare-free therefore does not apply to all people.

Assembly

• Soldering the parts to the jumper cables:
  

• Cutting and gluing the LED strips: The LED strip is separated into two times 6 LEDs and once 5 LEDs and glued to the intermediate cover. The cable opening on the lid for the plug must remain free:
  

• Attach the hollow bushing to the intermediate cover:
  

• Screw the battery shield into the housing after the ten threads have been previously cut into the housing.

• Press the rocker switch into the cover:

• Press LiPo 18650 into the receptacle

• Connect cable and turn on:

• If all LEDs light up, place the middle cover on the housing and then place the cover on the middle cover and screw it down:
  

Glare free lamp CAD design

For the threads, the holes are designed for core hole diameter, i.e. for M2 for diameter 1.6 mm. You can tap the thread with the tap or form (press in) with a screw. Personally, I prefer the thread cutting. The two graphics show where the threads have to be cut on the housing.

Further notes

Some may wonder why the rocker switch sticks out of the lid and is not recessed. It makes it easier to turn the lamp on and off.  Most of the time you only have one hand free and can’t really reach into the recess, but if the rocker switch sticks out it’s easier to operate it. Nevertheless, I have also designed a version with recessed rocker switch, which you can download in the download section!

The power of the lamp is about 1.4 watts. At 5.05 V the current is therefore 0.27 A, which is no problem for the Battery Shield V3 and the LiPo. The burn time of the lamp is about 5 hours in continuous operation. For this data, I used a Samsung 18650 with 3500 mAh. The powerbank can be used in parallel to run the lamp. However, the total current should not exceed 3A.

I use this lamp not only for my 3D printer, but also for soldering, reading or as a night light. The powerbank is also extremely light with 127g.

Download files

• STL files of the glare free lamp

The post Glare free lamp and powerbank appeared first on Nerd Corner.

This might also be interesting for you: Development of a step-down module

List of components:

• 1x Battery Shield V3
• 1x LiPo 18650

Analysis of the Battery Shield V3

After the Battery Shield V3 arrived, the first thing I had to do was examine its properties in detail.  I thought about the tests beforehand and they were primarily based on my use cases. Since I am of course not a research institute, I kept the tests as simple as possible.

First, I tested the main function, which is charging a LiPo battery. The charging process on the module is indicated by a LED. Red means that the battery is charging and green signifies that charging is complete. Unfortunately, the LEDs are located on the bottom of the module and are therefore not easily visible.

According to the information provided by the manufacturer or the online retailer, the charging voltage is 4.2 V and the charging current is 500 mA. To verify these values, I measured and noted the state of charge of the inserted battery. The state of charge was approximately at 1100 mAh. The total capacity of the battery is 3000 mAh. It appears that the difference between fully charged and partially charged is 1900 mAh. To get the expected charging time, this value is divided by the 500 mA specified by the manufacturer. The calculated charging time is therefore 4 h. A standard power supply with 5V and 1A charging current is used as the power supply. In reality, the duration of charging was 4 h and 15 min. This is close to the theoretical value and thus okay.

Please note: Never use a brand new LiPo battery for this test, instead use one that already has some charge cycles completed. Otherwise, the result is not very meaningful.

Voltage testing in the Review Baterry Shield V3

In the second test, the different voltages provided by the module were examined. I divided this test into two phases. In the first phase (picture test 2_1) the module is used without a LiPo battery. Afterwards in the second phase a LiPo battery is used.

Of course, it is important to choose the right components to make the test as realistic as possible. For the USB-A connection I selected a load resistor with 1 A as well as with 2 A. This ceramic load resistor is ideal because a USB interface is available and the LED lights up green when 5 watts are consumed. At 10 watts the LED lights red.

For the 3 x 5 V outputs, I soldered 5V LED strips to two outputs and the third 5V output has a step-down module LM2596S which I constructed and set to 2V to power a 10 mm RGB Led. 3 V LEDs were soldered to each of the 3 x 3 V outputs. For this test a 5 V (18 Watt) power supply was used.

The module operating without LiPo battery

After connecting the consumers and the power supply, not much happened. Only the module-internal LED lit up red. Only when I deactivated the ceramic load resistor one of the 5 V LED strips and the RGB diode connected to the step-down (marked yellow in picture Test2_1) lit up.

Subsequent measurement of the outputs revealed the following values: A voltage of 3.24 V was measured for the 5 V outputs and 2.28 V for the 3 V outputs. The total current supply of the module without the LiPo battery inserted is about 11 mA. This should be sufficient for a small LED.

The module with LiPo battery

For phase 2 all consumers were removed and a LiPo battery (SAMSUNG INR18650-35E SDI KL59) was inserted into the module. As shown in the pictures, connectors were attached. This is because this module does not have a switch for the LiPo battery, so the load is immediately applied to the LiPo battery. It is simply uncomfortable to insert or plug in a battery under load.

All loads are in full mode in phase 2 and work fine. In addition, even the LiPo battery is charged. Questionable are the 4A amperage specifications of the 5V outputs. Given the amp numbers of the LiPo battery, this is possible, but it seems very high for a USB Micro supply. My recommendation would be to use the module with less than 4 amps.

Deep discharge protection

The third and last test is rather trivial. To test the deep discharge protection, only the ceramic load resistor with 5 watts was activated and no power supply was connected. This discharged the LiPo battery and if the deep discharge protection of the module terminates the discharge process on its own, the test was successful. This was the case. There was enough remaining capacity. However, such stress situations for the LiPo battery should still be avoided.

Casing for the Battery Shield V3

Of course I couldn’t resist to build a case for the Battery Shield V3 module. Beside the normal 5V USB output, which can be switched on and off by an extra switch, I also constructed a constant 3V output with a 5,5 x 2,1 socket into the case.

The housing can be downloaded in STL format at the end of the blog post.

Minor disadvantages

The On/OFF switch only switches the USB port. The 3 x 3 V and 3 x 5 V solder pins cannot be switched on and off by this switch.

For my electronic projects this disadvantage is not really dramatic, because I use mostly the USB port. Besides, additional switches can be soldered to the soldering points.

Downloading files:

• Datenblatt Battery Shield V3 (von AZ Delivery)
• STL Files for the housing

The post Review Battery Shield V3 – DIY Powerbank with LiPo 18650 appeared first on Nerd Corner.