Electronics-Lab.com Blog

Brian Schmalz writes:

The UBW board is a small board that contains a Microchip PIC USB-capable microcontroller, headers to bring out all of the PICs signal lines (to a breadboard for example), only costs about $15-$20 to build and is powered from the USB connection.

UBW – USB Bit Whacker- inexpensive, simple input/output USB device - [Link]

photo credit: angrycamel.com

bobstarr.net has revised the default Eagle libraries to suit his electronics design work and facilitate the work flow. These library files are designed to completely replace the default Eagle library set and are updated frequently.

Cadsoft Eagle replacement Libraries - [Link]

Sudhansu Sekhar Mishra, Tarun Rehani, and Nishant Thakur write:

A regulator is a closed-loop feedback system. For the LDO to be stable, the phase margin must be positive. In other words, at unity gain crossover frequency of the gain curve, the phase of the system should be positive. This can be measured using a vector network analyzer. Many voltage regulators are of the fixed output variety and include the voltage divider internal to the regulator. There are definite advantages to this approach, which allows active voltage trimming and also minimizes the physical space required. A disadvantage to this approach is that the voltage divider is not available for gain-phase or “Bode” measurement. This leads many to believe that it is not possible (or even necessary) to evaluate the stability of such a regulator. This is simply not true.

Understand linear regulator stability - [Link]

Here is a great list of some Eagle tips on dangerousprototypes.com. Check it out..

Cadsoft Eagle tips and tricks - [Link]

photo credit: myropcb.com

I decided to order a prototype PCB for my latest project in a professional fabrication company but i could’ t decide if i should order it in a company in Europe or Asia. I am located in Europe and I wanted fast and quality service so it seemed that ordering from Europe will be the best choice. But i also was curious about the quality of the cheaper Asia manufacturers. So i concluded ordering the same PCB on both an Europian and an Asian PCB manufacturer. I choose the following PCB manufactures :

• Eurocircuits.com - based on Belgium
• Iteadstudio.com - based on Shenzhen – China

Eurocircuits.com – offers a great user experience when ordering a PCB. You place your PCB in shopping basket, you choose PCB details and you get an instant quote for your order (including shipping, excluding VAT). After placing your PCB in shopping cart you are able to review you PCB in PCB Visualizer. PCB Visualizer is a great tool to test you PCB for manufacturability online. My PCB prototype (2 layers, 1.55mm FR4, 1oz copper, green soldermask, white silkscreen, Lead free HASL, 100% E-test, .. more details here) costs calculated at 85 EUR for 2 pieces including UPS shipping.

Iteadstudio.com -  offers a pretty simple billing scheme, you choose from 5 sub-categories based on your max PCB dimensions. Quantity offered for each category is 5-10 pieces and prices are reasonable. I choose the 10x10cm batch offering 10 pieces (2 layers, 1.6mm FR4, 1oz copper, green soldermask, white silkscreen, Lead free HASL, 100% E-test, .. more details here) for a price of 24.90 USD + 25 DHL shipping = 49.90 USD final value.

Order on both manufactures done the same day. Both PCBs come to our door in 10 days. What we got:

• Eurocircuits – we received 3 PCBs in 10 days for 85 EUR. PCB quality is great, plating is more thick on bottom than top layer, pcb cut-offs from panel are visible, soldermask has a faded green color, there are marks from E-testing. Packaged on plastic bag (vacuum). Cost per PCB = 28,3 EUR

• Iteadstudio – we received 10 PCBs in 10 days for 49.90 USD. PCB quality is great, plating is more thick on bottom than top layer, pcb cut-offs from panel aren’t visible, soldermask is shiny vivid green color, there are marks of E-testing. Packaged on plastic bag (vacuum) + silica gel.  Cost per PCB = 4,99 USD 

I can’ t figure out any significant quality details between the two PBCs. To me IteadStudio PCBs seems more beautiful and worth the money. So i give +1 to IteadStudio for quality, quantity and processing time!

RFID modules SL102 and SL500A are readily usable and provide many useful functions.

Similarly like in other segments of electronics, even at RFID you have a possibility to assemble a target device from components themselves, from modules, or to use a complete ready-made module, which is pluggable to a PC, often already with a SW included. SL102 and SL500A modules represent the „3-rd group“ from this point of view and provide a ready-to-use RFID solution.

• SL102, 125 kHz RFID reader – USB keyboard emulator. That means, that after SL102 appears as a keyboard after connecting to a PC (PC automatically recognizes it). SL102 operates in the way, that after reading an RFID tag, it sends its ID in the same form as if we typed it via a keyboard (and finished it be pushing „Enter“), i.e. every ID is in a new line. It is only necessary to open any program in which it is possible to enter numbers via a keyboard (excel, notepad, word,…). This system is very convenient for example for tracking of goods in production, in stock (stock in, stock out) but also for admission systems and many other.

• SL500A,Mifare 13,56 MHz reader/writer with the USB interface (virtual COM device). SL500A is able to read and write Mifare_1k, Mifare_4k, UltraLight and Mifare_ProX cards (ISO14443A, ISO1443B and ISO15693 protocols). SL500A is supplied with the software, including a DLL library and examples. SL500A can be used by a supplied SW, but you can also create your own application best suited to your needs.

Both RFID devices are available directly from our stock. A detailed description will provide you the SL102 and SL500A datasheets.

“Plug’n'play” desktop RFID modules with a USB interface - [Link]

A clap switch is a fun project for beginners. It switches on and off electrical appliances with a sound of clapping hands. Today we will discuss about making a simple clap switch that operates when it detects two clapping sounds in a row. It uses an electret microphone as a transducer for converting a clapping sound into an electrical signal. The microcphone output is amplified by a transistor and is then sent to the PIC12F683 microcontroller which performs an ON/OFF switching action when valid claps are detected.

Making a simple clap switch - [Link]

Gio @  diyaudioprojects.com point us to:

This is a project that has roots to back about 2 years ago. I wanted a quality headphone amplifier to be an addition to my Hi-Fi stereo system. It was to be something to use when I didn’t want to disturb everyone else in the house. I tried several different tube types in the amplifier design process. I used 6J6, 12AU7, 6SN7, 6CG7/6FQ7 and 12AT7. Generally all worked, but none seemed to have either the needed output level or didn’t match well (likely to the choice of transformers) and sounded on the dull side. The 6DJ8 (ECC88) dual triodes worked like a charm. They had the combination of sufficient current flow, modest voltages on the anodes (important for the matching transformers) and enough gain to make the amplifier sing. The next best tube type was the 6CG7/6FQ7. Almost as good, but they are getting a bit scarce and the new production JJ E88CC are now quite common and reasonably priced. I am sure other triodes could be used and there is no reason why a high impedance ( on the primary side) small push-pull output transformer would not work. I doubt that you can find one much cheaper than the matching transformers I used. Certainly not with similar response and distortion characteristics.

DIY 6DJ8 (ECC88) Tube Headphone Amplifier - [Link]

Multifunctional gas soldering tool will help you at many various applications like: soldering, melting, hot-cutting, welding and woodburning (pyrography)…

This quality gas soldering tool provides a freedom of usage for example outdoor and everywhere where no electricity is available. But DREMEL 2000 VersaTip isn´t only a gas soldering tool with adjustable temperature. It is a multifunctional tool, which you can use, thanks to 6 exchangeable tips, for technical and also creative works like: soldering, melting, hot-cutting, welding and woodburning (pyrography), bending of metals, application of heat shrinkable insulations, releasing of junctions locked by an anaerobic sealant (bearings and screws) and many other.

Our friend Vassilis decided to build his own manual Pick & Place machine to facilitate his work with 0402 SMD and other fine pitch parts. He used plywood, a pen microscope and a vacuum pump to build this dirty cheap Pick and Place manual machine:

If you are dealing with tiny SMD parts (e.g. 0402 resistors and capacitors), a manual pick and place machine is a helpful piece of equipment for prototyping and small-batch manufacturing. On the other side, traditional SMD placement using precision tweezers not only requires an ultra-steady hand but also becomes a tiresome drill, especially when working long hours upon fine-pitch PCB footprints.

Low Budget Manual Pick & Place - [Link]