4-Button controllers? It's half-way thing

A project log for A 'smart' controller for a powered chair or bed

2023 "Assistive Tech" Winner! Automates the powered recliner or bed. Ideal for the mobility-challenged.

stephen-craverStephen Craver 11/28/2023 at 22:050 Comments

The "Logic" controller is designed to accommodate 4 button controllers, whereas my specific chair model originally features a 2-button configuration. Consequently, limited research and development were allocated to integrate 4-button support into this particular main controller.

I am currently in the process of overhauling the electrical components to facilitate native compatibility with 4-button controllers. My initial considerations suggest the necessity of incorporating an additional two relays, forming a potential 4-relay array. This is contingent on whether I opt not to utilize a custom PCB.

It's worth mentioning that two additional GPIO channels will be required to govern the newly introduced relays. However, a predicament arises due to the exhaustion of available channels. This situation demands careful reconsideration of my approach.

Recognizing this challenge, I have identified a solution by repurposing the existing LED controller channels, which currently allow software-based brightness adjustments. By employing appropriate resistor values, I can liberate four channels, addressing the shortfall and offering a feasible resolution.

Additionally, I am aware of alternative areas where GPIO channels could be sourced if necessary, including two unused limit switches. These considerations underscore the need for a comprehensive reevaluation of the project's design and implementation.