How (not) to sell PCBs: PCB drawer first year sales breakdown

A while back we started selling Bus Pirate v3.5a-SOIC “DIY Edition” PCBs from the free PCB drawer for $3.95. Our informal survey and found that $5, including shipping, is a sweet spot for one board. So we hacked Zen Cart to accept PayPal for only one item, and started taking orders. With shipping, two boards from the PCB drawer are $9.90, right in the $5 zone.

Here’s a breakdown of the trial, based on our 2011 sales tax return.

100 PCBs were made for $124.90, including shipping. We contracted fulfillment to handle and ship orders. They charge $25 for receiving the stock and warehousing it. We also provided our own envelopes ($21.67 with shipping). The total startup cost was $172.

In four months from September to December 2011 we sold a paltry 40 boards to 29 customers for 158 bucks, $227.25 including shipping. PayPal charged us $16.12 in fees, 7% or about 55 cents per order, to receive the money. Initial take: $146.94 in PCBs, $64.40 in shipping.

US shipping is under priced at $2, international is over priced at $3.25:

  • A US order runs about $0.88 in postage, 22 cents for the envelope, and $1 for fulfillment ($2.10)
  • Non-US orders are $1.25 postage, $0.22 envelope, and $1.25 fulfillment ($2.72). Initially international shipping bounced around a bit, as high as $4 total, but it seems to be under control now

We received $64.40 in shipping and handling. Our aggregate fulfillment cost was $81.69 for 29 orders, plus $6.09 in envelopes ($87.78). We lost $23.38 from PCB profits on shipping differences. This could have been avoided by doing it ourselves, but even then someone should be compensated for handling the order.

From the 40 PCBs sold we received $146.94, less $23.38 in shipping overruns ($126.56, $3.16 per PCB). Each PCB costs $1.25 plus $0.25 warehousing, leaving a profit of $1.66 per PCB.

With $66.40 of profit we can’t cover our existing costs like the remaining PCBs ($75), envelopes ($12.60), and warehousing costs ($15). In the end we’re $36 bucks in the hole in this experiment.

Obviously this is a failure in the business sense, but profit was never a motive. We wanted to:

  • Test real orders in Zen Cart with PayPal integration
  • Learn about the cost and time involved in retailing PCBs
  • Judge the demand for $5 PCBs
  • Learn about our local sales tax licenses and returns
  • Get a bit of publicity by putting PCBs into the hands of dedicated builders
  • Try something cool

All of these goals were met, so we consider it an overall positive experience. Definitely not something to expand or continue beyond the first batch though.

There’s still a handful of PCBs left, get one while you can.

Grab the raw sales data spreadsheet from Google Docs.

Bus Pirate v3.5 free PCB build

Cristian built a Bus Pirate v3.5 free PCB, and a custom machined case for it. The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

More user cases here.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Cotton Candy: thumb sized Linux computer


Cotton Candy is a mini Linux box in a package resembling a USB thumb drive. FXI Technologies, Inc., a Norway-based hardware and software startup which developed the product, has launched cstick.com, a community website and technical forum where Cotton Candy development units are immediately available for pre-order. (Unit shown in above video is an engineering sample.)

Specifications include an ARM Cortex-A9 (1GHz) CPU from Samsung, an ARM Mali-400 MP (Quad-core, 1.2GHz) GPU, Wi-Fi and Bluetooth, HDMI output and the Android operating system. It decodes MPEG-4, H.264 and other video formats and display HD graphics on any HDMI equipped screen. Operating systems supported to date include Android Gingerbread and Ice Cream Sandwich as well as Ubuntu. On-screen content can be controlled a wide variety of ways – wirelessly using smartphones with an app, Bluetooth peripherals like mice and RF remote controls; or by leveraging a notebook’s integrated keyboard and touchpad.

At $199 this seems a bit overpriced. We’ll keep watching for further information on their manuals and docs page.

The Hoz via the contact form.

PlayStation 2 controller Arduino library

Bill developed an Arduino library for PlayStation 2 controllers:

I had to rewrite a lot of code that powers the library, there is not much left of the original code written by Shutter of Arduino forums. There were many bug fixes, now the controller should automatically be in analog mode, and the mode button should be locked. There’s also a catch to make sure not to much time has past since the last controller reading. If there was, it will configure the controller again, in case it timed out.

Via Mecharobotics.

USB LCD Backpack PIC18F24J50 free PCB build update

Dolabra posted an update on his USB LCD Backpack PIC18F24J50 free PCB build. This version used a different chip than the 18F2550 we used in the final revision. The USB LCD Backpack connects HD44780-compatible character LCD screens to your USB port.

I put the bootloader problems aside and finished the UART support. This version will work from either USB or the UART. As proof see the picture of LCD Smartie running through the Bus Pirate in transparent UART mode

Get your own USB LCD Backpack for $16.95 at Seeed.

Via the forum.

Wardriving for ZigBee

Travis Goodspeed has assembled this wardriving project covering the ZigBee wireless protocol. It is designed around the radio module from the TelosB, which is used to sniff for nearby ZigBee/802.15.4 transmissions. This module is connected via serial to a Roving Networks RN42 module which provides a Bluetooth connection to the Nokia N9. Travis’ GoodFET firmware natively supports the TelosB module, and complete instructions for building and flashing onto the module can be found here. He also developed both a command line and GUI client for the Nokia N9 in order to control the TelosB.

Travis states: “The result is a complete wardriving solution for my Nokia N9, allowing for efficient mapping of ZigBee usage when walking or driving.”

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters.

Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Continue reading “#FreePCB via Twitter to 2 random RTs”

Using the Arduino Ethernet shield as a server

Luca shows how to turn your Arduino with an Ethernet shield into a server. He goes over how to code your Arduino to handle HTML and HTTP protocols using strings.

I’m going to show you a simple program that prints on serial connection browser‘s requests and answers with a simple HTML page. This program is useful to understand how to use HTTP functions and also to find out which informations a browser sends within the request (you’ll learn how to use those informations in a coming post).

At the bottom of the page he showed an example of page icon usage, for which he used our site. Thanks Luca!

FTDI’s new X-Series of USB device chips

FTDI just released a new series of their USB to serial device ICs. The X-series is an upgrade on the R part used in the Bus Pirate and formerly in Arduinos. It features better transfer rates, lower power consumption, needs fewer discrete components, and has high power USB charging capability.

FTDI is delighted to announce the launch of its new X-Chip series. Made up of 13 devices, with an exception feature set, the X-Chip series offers full speed USB 2.0 bridging solutions to UART, SPI/FT1248, I2C and FIFO interfaces complementing the company’s existing R chip, and Hi-Speed solutions. “By specifying the X-Chip into their designs, engineers will reduce their overall bill of materials and optimise PCB real estate,” states Fred Dart, CEO and founder of FTDI. “With its comprehensive feature set, the benefits of lower power, smaller device footprint and NEW enhanced battery charger detection can all be realised, as well as the robust USB functionality that FTDI has always provided in its connectivity solutions”. In addition to the ICs, FTDI has released a wide-selection of development modules, enabling instant access to the different functions for each chip type, and thus allowing for easy device evaluation and prototyping development.

Referral: https://goldenpandacasino.com/

Boot your PC with the Arduino using the Wake on Lan command

Luca explains how to boot your PC with a Wake on Lan command sent from an Arduino. Setup the WOL feature on your PC, then use the sendWOL() command to send a magic packet via and ENC28J60 ethernet chip:

The wake command is issued sending on the network a specific packet, called Magic Packet. This packet is receved by all the devices connected to local network because it presents – as destination MAC address – the broadcast address (FF:FF:FF:FF:FF:FF). It includes six bytes valued FF, followed by the target PC’s MAC address repeated 16 times.

Weller RT type tip teardown and reverse engineering

Raj has been designing a soldering station that would support Weller’s RT type tips with temperature sensor and heater built into them. A stereo-type jack on the iron connects them to the soldering station cable.

So far Raj has reverse engineered the pinout of the jack and how to read the temperature. The tip has an integrated k-type thermocouple that should be read when power is not being supplied to the heater.

Via the forum.

28C3: The Atari 2600 video computer system ultimate talk

Here’s something for retro video game enthusiasts. This talk by Sven Oliver (‘SvOlli’) Moll from the recent 28C3 conference in Berlin covers the history, the hardware and how to write programs for the Atari 2600 gaming console.

The Atari 2600 Video Computer System (VCS for short) was one of the first popular gaming consoles back in the day. It featured 128 bytes of RAM, 4k bytes of addressable ROM and was in production in one form or another for more than 13 years.

Starting at 19:33 is an overview of the chips used in the Atari 2600: the 6507 CPU, the 6532 RIOT (RAM-I/O-Timer) and the TIA (Television Interface Adapter). Coding is discussed, covering the registers and how to use them.

PCB ecthing at home using photo transfer method

Blondihacks wrote an in-depth tutorial on how to make PCBs made at home using pre-sensatived photo-PCBs. We especially liked the board design optimization for home etching tips. Wide traces, big vias, and using a ground plane are all strategies we use to get good DIY photo-transfer PCBs too.

DIY etching is the fastest way to get your prototypes made, but if you find it too much of a hassle there are lots of cheap PCB fab houses. You can check out our tutorial on how to get your PCBs manufactured.

Via Electronics-Lab.

3D Model: USB Infrared Toy v2.0

Our latest 3D model is the USB IR Toy v2.0. We continued to play around with Maxwell’s free rendering plugin for SketchUp. We were especially pleased by the glass rendering of the LED.

Exporting the rendering with a transparent alpha background has proven to be a challenge. If you know of an easy way to achieve this please let us know via the comments, or the contact form.

The models will be published in the Dangerous Prototypes 3D warehouse collection. They are also uploaded to our SVN. You can find them inside the “art” folders in the respective project folders. Check out the 3D view below. You can zoom and rotate the model.

Continue reading “3D Model: USB Infrared Toy v2.0”

SignalTap II integrates a logic analyser into your Altera FPGA projects

SignalTap II is a tool that embeds a logic analyzer into your FPGA project so you can see what is happening in the design. Kiran made a video tutorial on the basics using Altera’s Quartus II IDE.

The advantage is that, there are no need to connect any wire or probe to the circuit. Every signal rooting is done internally. Here is the short video tutorial for the inbuilt logic analyzer comes with QuartusII software. Towards the end of the video, while running the SignaltapII analyser one can clearly see and analyse the PWM waveform.

3D printed wire stripper with a wire contact indicator

Bjbsquared designed a wire stripper tool with a LED indicator that flashes when contact with the wires is made. To built it you’ll need to get the model laser cut from acrylic or 3D printed.

This is one of the best wire strippers I have ever used. If setup correctly, it can be very precise and give feedback telling when the blades have cut deep enough.

Via Gadget Factory.

App note: Designing the oscilator circuit for PIC microcontrollers

Here is an app note from Microchip describing how to design oscillator circuits for your PIC projects. The article advises designers to think about the conditions the project will be used in and design their oscillator circuits accordingly. Also provided are examples how to test and tweak the oscillator circuit to get the best result.

Oscillator design requires knowing the operating conditions under which the oscillator will function, followed by testing to ensure that it will actually function as expected. The design phase involves component selection, sometimes guided by initial testing. The testing phase tests oscillator performance, either by
testing actual operation under the previously specified  conditions or by ensuring that there is sufficient gain margin to allow start-up and operation under all conditions. Several other factors, such as circuit board layout, signal levels and crystal and resonator concerns, are also discussed and may be helpful
during the design phase.

MUN Sailbot autonomous sailboat


Jordan S (who scored one of our VFD tube sets) is part of a bunch of students from Memorial University, St.John’s, Newfoundland, Canada, trying to build an autonomous sailboat instead of focusing on their studies. Their project is known as Munsailbot. “As a team we are designing, fabricating and programming a fully autonomous vessel which will compete in match racing, station keeping, and long distance races. The ultimate challenge will be to send an autonomous sailboat across the Atlantic ocean.” They are open sourcing all their hardware and code. (Their board and schematic files are available from filehosting.org.)

For project update and more info visit their blog or webpage. A local company also did an article profiling their project.

Via the contact form.