The problem with connectors

Ever since (the Jurassic Period?) I realised that the intended spring connectors have a very serious weakness, I opted to go with a more no nonsense ‘traditional’ screw terminals. Which is great except that it takes up much more space than the former terminals. I have spent the whole day trying to remember what I did since the last revision was 3 weeks short of a year. The change in the terminals means I have to re-wire the whole board. And with so many LEDs (about 65) that needs to be connected, I ran out of space very fast.

Everyone is working overtime

Let’s look at the problem. After taking a few minutes of actual break, I have come to realise a few things:

1. The PCB is set in stone
   Whatever ideas or stunts I am going to do, the size of the PCB will NOT change and neither are the five 2mmx5mm rectangular LEDs at the rear. I can extend some areas but at this moment in time, there is not much I can save except to give the 5 rectangular LEDs more breathing space. Until the whole board is wired this is the policy.
2. Version 6.0
   Version 6.0 has two different connectors which I am not too comfortable with. The lower connectors were meant for pin headers which would lead me to crimping wires and soldering every LED. At first, it was OK since I was designing this board for myself. But after much thinking, even myself would reject this design as there is too much work.
   
   This version was also my last with manual routing. In the beginning, it was fun because I like to route those traces around the board, trying to keep everything on one side of the board. Soon, my designs went from single sided to double-sided because of my wanting principle of keeping the PCB as compact as possible, no soldering of jumper wires and well, the JCLPCB does them with no extra charge.
3. Version 8.0
   If you want to know, version 7.0 was me creating a circuit diagram so that I can auto-route it. Yeah, if you look at the circuit diagram, auto-routing is the way to go. Plus, version 6.0 was my last PCB design using manual routing. Anyway, for this version, I have decided replace all connectors with those 3.81mm screw terminals. The only issue was that it is still bigger and there is only so much I can fit into the board.

Delegating the PWMs

While I was re-wiring the board, I had another hard look at the circuit. There are some LEDs which I have forgotten their functions but the more important is, they are static. They are also controlled from a microcontroller in my efforts to save as much battery energy as possible. So, I am going to delegate this job to a real PWM module instead of stressing the microcontroller, which can then use its ports for more LED effects. However, the connector count is still the same and I’ve come back to square one. Sigh.

Reducing the Voltage

A few days ago, I just plugged in a 3.7volt Lithium-ion battery into it and it works. If I am not mistaken, the circuit was designed for 5volts which was USB charger ready. Most of the LEDs in this design does not exceed 3 volts and so, I am thinking very hard about adopting it. A decade ago, it was 4.5volts/ 5 volts because of the common AA/ AAA batteries and portable USB mobile phone chargers. Now, as I foray into Lithium-Ions and Lithium-Polymers, the advantage of having power in a compact size is so attractive.