PCB & Hardware Design

pmolver — Sat, 24 Jan 2026 14:12:34 +0000

PCB & Hardware Design

In University

University gave the a wide range of experiences in PCB and Hardware design. Several projects required custom PCBs and KiCad was the tool of choice in early years for licensing reasons. Many of my early projects were simple Arduino hats with only a couple features such as an ADC on board.

Personal Project

In later years, in Embedded Systems 2 I got to create the PCB which would control the racer body, and this included placing and soldering the individual components on the PCB.

In my free time, I worked on a project called GrowSimple, this device was a simple watering device but due to feature creep, it’s resulted in a device that does more than simply turn on and off a 12V water pump. This has had several challenges, such as how would I assemble and enclose the PCB? How can I create something somewhat modular as different micro gardens require different features, and how do I provide value for a product that will be expensive due to it’s low volume nature?

Features and Challenges

The Grow Simple project was interesting to work on due to the various challenges I had to overcome;

User Control – The beauty of the ESP32 is the cost and feature set, having BLE available meant I could create a web based user interface to interact with the device, without any server cost, or app store fees. The problem is feature creep and development time to implement all the features required such as file transfer and OTA updates.

Device Status – I picked a side mount RGB component and have a small acrylic tube that sits in a custom 3d printed wire grommet, this acts as a light tunnel and allows for the device status to be seen by the user while ensuring that the water tightness of the device remains.

External Modules – The D-C pins at the top of the PCB are for data and clock, I use I2C to allow for devices to be plugged into the device, and the device can scan for connected devices on boot and then display the relevant BLE characteristics. This was challenging as I was not able to find a low cost, consumer friendly plug for this application. I instead used a 4 pole 2.5mm audio jack as this is intuitive and easy to source for a low cost.

Power and PCB – The small enclosure I picked meant that I had limited space to work with but I still managed to implement a buck converter to 5V for external modules, and another 3V3 LDO regulator for the ESP32. The 5V module power was picked to allow for more variety of external modules, more power availability to them, and a better Signal-Noise ratio.

Industry Experience

Working at OnFarm Data gave me many opportunities to both work with different software, and learn from the best. Working here I learnt how to better implement power planes, share and discuss ideas for the hardware I was developing, testing and test strategies, and document both the PCB details and assembly instructions.

Pictured is a small project I worked on that was essentially a solar charger for a Li-ion 18650 battery which was common in our products. This allowed for two different panel types to be selected for the MPPT and charging chip.

In addition to smaller modules just mentioned, I also worked on large projects that were core to the company focus such as an exclusion Input/Output PCB. This project featured an Input IO expansion module, and a second for output, and using I2C and an I2C range extension module, a series of up to 4 PCB could be placed on a pivot controlled by a single micro controller allowing for 64 additional inputs and outputs available to the micro controller.

This PCB had to allow for 12V or 24V input, and the input logic had to account for 2 possible logic levels being returned. Additionally, due to the 16 channels on the PCB, this was a tight design that tested my routing and component placement abilities.

For safety, each output had a surface mount resettable fuse to ensure that in the case where the output wire was damaged, that the rest of the installation was capable of performing it’s job until the cable was fixed. There was also reverse polarity protection and an RGB led to indicate the address of the PCB to allow for easy confirmation that the DIP switch was correct.

The post PCB & Hardware Design first appeared on parismolver.com.

Field Servcing

pmolver — Thu, 22 Jan 2026 09:15:30 +0000

Field Servicing

Roles & Responsibilities

During my time at OnFarm Data I had to perform a variety of roles, one being field servicing for a variety of products.

• Servicing and install of data loggers and control which required PCB upgrades, or needed GPS, 4G, or LoRa connection troubleshooting.

• Troubleshooting sensor failures such as weather stations which were no longer recording pulses. Sometimes this would be due to a cow ripping the cable out and solving the problem with better cable routing and protection.

• Servicing and install of post irrigation control units. These were LoRa based and could sometimes be fixed without replacing the entire unit.

• Servicing, adjusting, and troubleshooting base stations which bridged large LoRa networks to the cloud.

Process Improvement

Sometimes servicing was a constant back and forth between people in the office, and people on site. Using a Raspberry Pi I was able to create a package that would act as a reference unit, being able to simulate a base which acted as the central unit in a star based LoRa mesh. This had several advantages.

• SD card swapping allowed for the same software to be transported to a different physical unit quickly and efficiently. This meant you could quickly test if it was a hardware problem, or if the location was an issue.

• SSH based LoRa sniffing. This allowed the engineers at the office to have an additional source of truth when trying to diagnose issues. If one unit saw an incoming message whilst another didn’t you can at least confirm that a unit had missed the message. All of this could be done via SSH reducing the need to verbally communicate over the phone.

Creating Service Flow Charts

Whilst I was given minimal training for servicing a LoRa based product in a large scale network, I managed to find out what the most common problems were and what was the potential on-site solution. Using this information I have gathered, I was able to make a simple flow chart which could be agreed on between me and the senior engineers for what the potential problems could be. Navigating the flow chart allowed us to better communicate what trouble shooting steps had been undertaken and allowed this information to be used as training documentation for future employees.

The post Field Servcing first appeared on parismolver.com.

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PCB & Hardware Design