Enginursday: Efficiency Gains thru Design

Efficiency is the secret at the present time, and the SparkFun QC workforce is all about it! We have effectively deployed a brand new test-fixture we’re calling the “Qwiic Test-bed” and I’m right here to let you know all about it.

If you might be new to SparkFun or haven’t stopped by means of for some time, you is probably not conscious about our Qwiic line of goods, if that is so, take a look at this Qwiic explainer. Being a top variation electronics producer, we in QC stay very busy designing checking out {hardware} and instrument for brand new SparkFun originals. We are at all times looking for and profit from potency positive aspects to extend the bandwidth of our three-person workforce, and the brand new Qwiic Test-bed does simply that. Below is a short lived assessment of the reasoning, technical main points and result of growing with our new test-fixture.

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The Motivation:

We sought after to have the opportunity that we, as a workforce, may building up our bandwidth by means of saving time growing. Typically we design a test-bed for a product, and that test-bed is handiest used to check that exact product. This manner for each and every new product we need to: design new checking out {hardware}, construct the brand new test-fixtures, write the instrument to keep watch over the test-fixture and verify the product, and deal with the test-fixture thru ongoing Production use.

One of the perfect steps we will take to save lots of time all through our {hardware} design procedure is to repurpose previous design information and make adjustments to fit your present application, and the similar may also be carried out for checking out instrument. But even with those potency positive aspects we will’t outrun the turnaround time on test-fixture {hardware}. What we wanted was once a bodily test-fixture which may be reused to check new merchandise whilst nonetheless supporting the previous.

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The secret to meaking this test-fixture conceivable was once partially because of the standardization in sort component and pinout of the Qwiic breakout forums, and partially because of the entire forums using the I2C verbal exchange protocol. One laborious same old was once set with regard to form-factor, this same old dictates the ordering of the four crucial plated thru holes (PTHs): flooring (GND), energy (VCC), I2C information (SDA), and I2C clock (SCL) (they should even be adjoining).

It must be stated that this test-bed was once by no means supposed so to verify each Qwiic breakout board, we simply need to seize the bulk – some designs simply want to ruin the usual for one reason why or every other, and seeking to design a fixture round all of the conceivable deviations would have led to an excessive amount of scope creep.

The level of the workout was once to expedite as a lot of the advance procedure as conceivable when the usage of the Qwiic Test-bed. We opted to make use of a collaborative firmware caricature that runs at the test-bed, permitting us to construct at the test-bed firmware by means of simply including new product supply information and checking out purposes required to check new designs. This supposed that shall we now use the similar bodily test-fixtures to check a couple of assemblies, thus saving time on build up {hardware} for each and every new design. By disposing of the want to design and bring together a bodily fixture we’ve stored a host of our workforce’s time, and in addition allowed the product cycle to transport faster. As an added bonus, the fixture can be used all through the prototyping segment to check new {hardware} and instrument.

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The Qwiic test-bed makes use of pogopins to make a brief connection to the board’s PTHs whilst the board is held in position by means of the hinged acrylic bar at the best. A small nubbin may also be spun to stay the bar clamped at the board all through checking out, or the person can manually cling the bar down. The processing and checking out peripherals for the test-fixture are treated by means of our unique checking out advancement board referred to as the “Flying Jalapeno.” Check out Pete’s posts concerning the advancement of the Flying Jalapeno right here:

  • Enginursday: Innovative Testbed Design (Part 1 of 2)
  • Enginursday: Innovative Testbed Design (Part 2 of 2)

The test-fixture has two to be had capacitive sensor pads, four LEDs, and to be had serial debug for the person to interface with.

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The fixture facilities across the four major pogopins: GND, VCC, SDA and SCL, which might be separated by means of a regular 100 mil spacing. Because many of those assemblies get away different alerts similar to interrupts, allows, analogs, PPMs, clocks and serial RX/TX, the four crucial sign pogopins are straddled by means of eight additional pogopins – four above and four under. Five 74LVC4066 quad switches course probably the most functionally succesful pins from the Flying Jalapeno’s ATmega2560 to the eight additional pogopins, giving the developer the power to make a choice which pins of the 2560 to hook up with the test-board’s alerts, and which to disconnect.

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Qwiic Test-bed Schematic (PDF LINK)

By making the acrylic mating floor for the PTH connections slender, a test-board may also be put on both sides of the mating house to fit any PTH header orientation. Alignment is facilitated by means of matching the silk of the test-board with that of the test-bed. In maximum situations, the meeting being examined has fewer PTHs than the test-bed has pogopins; when a pogopin isn’t getting used it’s driven down by means of the PCB and separated from any sign by means of the masks. Reports about utilization from our Production division were certain, and the {hardware} is maintaining up smartly.


As an entire we’ve been more than happy with the result of the usage of this test-fixture. The three people in QC are getting a lesson in instrument collaboration, however with a couple of laws carried out, co-development has long gone easily. As a coarse calculation, the checking out advancement procedure for the forums being examined with the Qwiic Test-bed took about 25 % of the time they’d have up to now, and with all of the tasks within the pipes, saving any period of time is welcomed.

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