From Breadboard to Enclosure - Part 2

A project log for Street Sense

Portable electronic device to measure air and noise pollution

Mike TeachmanMike Teachman 06/19/2019 at 14:130 Comments

Building the power conditioning module for the particulate sensor is the subject of this log.   The components in this module include all of the MOSFETS, transistors, diode, and the DC-DC boost converter.   An overview of the modules was described in From Breadboard to Enclosure - Part 1

The components are shown below.  The full schematic is here:  schematic.

A soldered protoboard will be used for construction.  For protoboard, I either use Adafruit Perma-Proto (left in photo below) or a generic stripboard (right in photo), cut to a custom size.

The Adafruit product is high quality - the through holes are accurately drilled and plated.  The stripboad is somewhat lower quality - no though hole plating and inconsistent drilling which can lead to track lifting if there is any rework.  The photo below shows some of the off-center drill holes on the stripboard.

Sloppy drilling in stripboard

However, compared to a Perma-Proto board a stripboard module can be designed with a denser component layout, leading to a smaller module.  In the end, the need for a small module size led to the selection of stripboard.  

Related stripboard idea:   There is high quality stripboard that is available, but it comes a significant price premium.  I think it might be possible to design a stripboard in KiCad and then have it built by a custom PCB manufacturer.  I am seeing low-cost PCB manufacturers offering 3 PCBs (10cm x 10cm) for USD $10 + shipping.   These PCBs would have plated through holes and solder resist between the holes, and hopefully accurate hole placement.  I might explore this avenue and document the results in a Hackaday project.

The completed power conditioning module is shown below.  I am using polarized JST connectors for connection to the particulate sensor and cpu module.    

The upcoming Part 3 will detail the construction of the stripboard that contains the Spec Sensor modules.