Friday, April 24, 2020

How to ruggedized Arduino Boards

Arduino boards, while affordable, are not designed for harsh environments. However, by implementing proper protection circuitry, these boards can be made suitable for industrial use.


A company in the United States is currently developing ruggedized Arduino-compatible microcontroller boards. They have shared valuable insights on their website, detailing ways to enhance the boards' durability and offering solutions for common issues. You can find the link to their website below.

https://www.rugged-circuits.com/10-ways-to-destroy-an-arduino


Implementing Ship Mode to Your Product

As global manufacturing and distribution increases, many original equipment manufacturers always look for creative ways to extend battery life during shipping and shelf life at big-box warehouses. Keeping the battery sufficiently charged during shipment enables a consistent out-of-box experience for the end-user. A solution that has gained popularity is using a ship mode feature that keeps devices in a low-power state during shipment and while on the shelf. Here is my solution using a load switch from TI, TPS22915B.

This is how the circuit works. Before the button is pressed, the solution is in ship mode, meaning that the system is not powered and the TPS22915 B load switch is turned off. When the button is pressed, the voltage from the battery is passed through the PMOS to the ON pin of the TPS22915B. The voltage enables the TPS22915B, brings VOUT high, turns off the PMOS, and powers the system. The ON-pin is pulled up to VOUT, which makes keeping the load switch enabling even after the button is released.

Wednesday, April 1, 2020

Making your own PCB by Etching method

1) Artwork Printing: 

Print your artwork on a transparent sheet.

2) Exposing:

Kinsten Presensitized PCB is used for this prototype as it is low-cost and easy to work. Remove the light-proof protective film and expose the board in the Kinsten UV exposure box for 90 seconds.
Align the artwork with the PCB inside the vacuum clamp, and leave it inside the exposure box for about 5 minutes.

3) Developing:

A sachet of DP-50 developer is mixed with 1 liter of 25°C water in a plastic container. The exposed PCB is gently agitated in solution. The exposed areas of resist will dissolve into the solution, leaving the green resist in areas that were not exposed to UV light as below.


4) Etching:

Etching copper is done in the Kinsten Etching Tank for 4 to 10 minutes. Pour enough etching solution (Ferric Chloride or Ammonium Persulphate) into the tank and immerse the board. Use the air pump to allow the etchant to be bubble agitated until the unwanted copper foil is etched away, only the circuit patterns are left. Rinse the board with plenty of water.
Remember “Safety First” always wear rubber gloves and protective eyewear when working with this etching compound. Once you've etched your board, the leftover solution should not pour down the drain (legally). Take it to a hazardous waste facility.

Here is the final outcome. For better results, make PCB trace thickness at least 10 or 12 mils and leave a wider gap between trace and GND copper pour.




Designing Thermal Vias

Enhancing thermal transfer for FR-4 PCBs can be achieved cost-effectively by incorporating thermal vias and plated through-holes (PTH) betwe...