DC/DC switcher for 5v TO 3v at 750mA in a TO-220 7805 footprint

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An open source small DC/DC 3W switcher to drop 5V to 3V in a 7805 TO-220 pinout from Black Mesa Labs:

This post is an open source hardware design from Black Mesa Labs for a simple DC/DC converter for dropping 5V to 3.3V ( or adjustable to lower voltages via resistor selections ). The design is based on the PAM2305 from Diodes Incorporated, a great little 1 Amp step-down DC-DC converter in a small TSOT25 package. The PAM2305 supports a range of input voltages from 2.5V to 5.5V, allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH cell, USB, and other standard power sources. The output voltage is adjustable from 0.6V to the input voltage.

More details at Black Mesa Labs site.

Open source 22mm diameter PCB project

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An open source 22mm diameter PCB project from Concretedog, that is available on github:

So I posted a while back about how I had used these 22mm pcb’s I’d made in prototyping an ematch ignitor system for use in rocketry. Although I made these stackable boards so they would fit inside a popular size of Estes rocket body tube I’m aware that they are quite useful for lots of things. So i’ve open sourced them so anyone can get some made, or add improve or change them.
There are three boards,an Attiny85 board with some power LED and indicator LED, a SOT89 power supply board which could be built up with either a 3.3v or a 5v supply. Finally there is a “kludge” board which is useful for adding in some thru hole components into the system. Some quick pics here but in the files on Git each board is well documented in a pdf. All the dust components are 0805 so super accessible for hand SMD soldering. :)

See the full post at Concretedog blog.

App note: Adding flexibility by using multiple footprints for I2C™ serial EEPROMs

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Save PCB space by utilizing EEPROM SOIC-8 area, here’s an application note from Microchip. Link here (PDF)

For many years, the 8-lead SOIC package has been the most popular package for serial EEPROMs, but now smaller packages are becoming more commonplace. This offers a number of benefits; the reductions in footprint size and component height are some of the more obvious ones. Smaller packages also generally offer a cost advantage over their larger counterparts.

Overdrive guitar effects pedal

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Eddie over at Bantam Tools shared detailed instructions of how to build this DIY overdrive effects pedal:

This project shows you how to make your very own effects stompbox! We’ll go through the steps of downloading the .brd file, loading the file into our software, milling the board on the Bantam Tools Desktop PCB Milling Machine, and soldering the components. This is a great tutorial for those new to milling printed circuit boards (PCBs) or for those who want practice soldering components to the board as a part of a larger assembly.

More info at Bantam Tools project page.

App note: PCB routing methodology for SuperSpeed USB 3.1 switch family from ON Semiconductor

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Routing USB 3.1 traces app note from ON Semiconductor. Link here (PDF)

The introduction of USB Type−C has provided a significant launch opportunity for USB3.1 data rates across an array of platforms from portable to desktop and beyond. This proliferation of Type−C will certainly create challenges due to the high speed nature of the interface. High Speed USB2.0 presented enough of a system design challenge for tiny mobile device OEM’s trying to pass USB eye compliance. A 10X or even 20X increase in data rates will propagate that challenge far beyond the issues that were raised with HS. PCB traces in these systems must be treated as sensitive transmission lines where low-loss impedance control is king. Every effort must be made to make these paths as ideal as possible to prevent signal loss and unwanted emissions that could infect other systems in the device.

Pimp your PCB businesscard full color

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Here is a nice PCB businesscard @ smdprutser.nl

As a good electronic hobbiest tradition I started to design a businesscard from PCB material. Downside of all the businesscards (and PCBs in general) is the limited number of colors you can use: FR4, soldermask (with or without copper behind it), silkscreen or bare copper. Since the soldermask is fixed for both sides that was an extra limiting factor.
An out of the box solution I found was decal slide paper. This is a printable plastic film that is used to decorate ceramics or glass. There are clear and white versions and they can be found in most hobby stores. They are easily printed on by an inktjet or laser printer and have thus an infinite range of colors. For this experiment I bought clear film and designed the PCB with black soldermask (needed that color for the front side) and white silkscreen.

More details here.

PCBWay

If you follow my blog, you probably noticed that I use different online services to make my PCBs… it’s a way to test them in terms of quality and production time.

On the advice of my friend Mauro, I recently chose PCBWay to produce some PCBs for my future projects.

The procedure for sending a new order is very simple; first you have to enter some information about your PCB:

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then, in the next page, you can configure som specific details of your printed circuit board (color, material, finishing, copper size…). It’s interesting the possibility – not often available – to choose the color of the silkscreen:

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Once selected the production mode (nomal = 2-3 days or express = 24h) and the shipping method, you can add the PCB to your shopping cart and upload the Gerber files of your project. PCBWay doesn’t offer the CAM jobs for Eagle, but I verified that they accept files in the same format of Seeedstudio. If you use Eagle, you can therefore follow my tutorial to create the needed Gerbers.

Before being able to complete the payment and send the PCB to the factory, the files must pass a manual check. Yes, PCBWay manually verifies every file you upload… this process requires only some minutes and it’s definitely an added value: in one of my orders I made a small mistake and I was promptly contacted by a PCBWay engineer with an email reporting the mistake and asking me for the correct file.

When the order is in production, you can follow the progress in your personal area:

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Even the website displays every step of the production process:

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The quality of the PCBs I received is very good, certainly comparable to other services I used in the past. The price also is alined to the other manufacturers and PCBWay does offer an entry price of 5€ for 10 PCBs (10x10cm max).

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Magic Mote MSP430G2553 wireless sensor node with NRF24L01+ module

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Tom from Magic Smoke writes:

This is my first time designing a PCB for MSP430. I really like the NRF24L01+ booster pack but I would like something smaller to use for remote temperature sensors. With that in mind I’ve designed a 24.5 x 50 mm PCB (2 on a 5×5 cm prototype) featuring MSP430G2553 and an adapter for a 8-pin NRF24L01+ module using essentially the same pinout, with the intention of using the Spirilis library. There’s a jack socket to connect a 1-wire sensor (e.g. DS18B20), a 4-pin header to connect a temperature/humidity sensor (SHT22 or similar), a programming header that gives serial access, and 3 other general purpose I/O pins.

More details at Magic Smoke blog.

DIY programming adapters

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Sjaak writes:

Today came in a new batch of PCBs from DirtyPCB.com, of which one is a new revision of the BlackMagicProbe. This revision is almost the same except it has a polyfuse in its powersupply to the target, a dedicated voltage regulator instead of P-FET, its programming header on the 90 degree on the side and a jumper for entering DFU mode. All this goodness is contained in less 5×2 cm PCB space, so quite a bit of PCB estate is left for other purposes and I used panelizing in EAGLE to try another brainfart of mine.
In most DIY projects where pogo pins are used people solder them directly to a wire or pad on a PCB. Despite it looks like it is the way to go, it isn’t. Pogo pins tend to wear out relative quickly as they are only rated for a couple of hundred ‘compressions’, also solder can sip into the pin and ruin its spring.

More details at smdprutser.nl.