Project update #1

Posted on Posted in BlogPost, WDBP Project

When I started this blog it was partly to track the progress of my latest project, briefly mentioned here. Over the month or two following the original post a number of issues were discovered with the original design. It used a TI wireless module that proved to be problematic in prototype assembly, mostly because all of the external connections were under the module. Added to this the antenna matching components were tiny, smaller than grains of rice.

Needless to say I became concerned that the yield on a production run would be poor and in addition the potential for a lot of rework was higher than I wanted to risk.

A little research revealed a Microchip module that seemed to address both of these issues, the WINC1500 (formally an Atmel part). The package connections are on the edge of the module and the antenna and matching components are on the module itself. The latter also meaning the FCC approval for the module would be transferable to my product.

Since I had not done any breadboard testing of this new module I decided to purchase a couple of breakout boards from Adafruit. The breakout module was put onto an Arduino breadboard and plugged into a Nucleo-F401RE.

This arrangement allowed me to begin testing the hardware interface between the MCU and the wireless module, plus investigate the driver requirements for controlling the module.

The difficulties of getting support for the module were part of a couple of earlier posts. However, the issues were eventually resolved and I moved on the the new PCB design for the project.

As a part of this re-design I decided that I would add the ability to power the device with a battery and to add a battery management and charging circuit. The new PCB was manufactured once again by OSHPark and hand assembled by a technician I have known for many years.

While there were a couple of minor errors in the design and two assembly errors, testing of the new PCB went well and now the firmware is under way once again. I had abandoned writing more code until I had a stable hardware platform.

Just yesterday the device attached to my wireless network and responded to pings from my PC. The next step with the firmware is to create a TCP server and to implement the data link between the PC and the core software.