Hi, I just received my Tiny FX in the post and have just now realised it uses what are rather rare connectors, and having just seen the 2 pin JST-SUR connectors become available from Pimoroni (“New!”), I’m now putting in a second order for those.
With a package of connectors I would like to be able to connect normal discrete LEDs to the Tiny FX. Could you provide a simple schematic or a description of what is necessary to connect an LED, or several LEDs? Is there a recommended resistor size?
Not knowing your level of knowledge I will work from Adafruit examples, reference below.
You will need to check your LED spec sheet for the exact numbers.
The Tiny FX supplies 5V. An LED drops somewhere around 2.2V. This leaves 2.8V across the resistor. For a current of 20mA this requires a resistance of 140 Ohms. Because we do not respond to brightness in a linear way, you can play safe and use a higher value without much perceived loss of brightness. I would suggest 220, 330 or 470 Ohms.
Adafruit has some advice on this.
Just substitute the Tiny FX output for the battery in the diagrams with the 5V out being the plus terminal.
I suppose I first plugged an LED into a solderless breadboard in 1978, but it’s safe to not make any assumptions about your audience, and you’ve supplied the info I needed, which is that I can treat the outputs from the Tiny FX as a typical 5V supply, with dropping resistors chosen as you suggest.
There’s quite a lot of information on the product page, and while I can possibly extrapolate from the 1A rating of the whole board, it might help to list the voltage and maximum current per channel to avoid people needing to ask this sort of question in the future.
I must confess I have capitulated and ordered the Starter Kit. I think this board breaks some kind of record for number of different connectors per square cm! 0.8mm pitch! I have only just got on top of making up 1mm pitch SH cables.
We need the enthusiastic Kevin McAleer to put up an intro/tutorial on Youtube.
I help with a public model railway and we are already using a Plasma board to control ambient lighting. I intend to use the Tiny FX to switch building lighting. I know I could use the Plasma or a standard Pico but this simplifies the installation (modular) and I hope it will make long-term support easier.
Yeah, five different connector types on a tiny board, a bit over the top.
You might be interested in knowing of a GitHub repository I wrote that could be used to connect the Tiny FX to a Raspberry Pi (or other I2C processor) as a slave device, the idea being that I could send commands from the Pi to the RP2040 to control the lights. I’ll probably flesh out the repo once I’ve actually got the LEDs in hand, but the basic master-slave functionality works.
It seems you have already found an answer to this, but yes, treat the outputs as regular 5V and choose a resistor value according to your LED’s forward voltage. The LED accessories for TinyFX have resistors ranging from 75R to 220R.
Each output is actually able to handle up to 600mA, but with that 1A current rating you would only be able to achieve it on one channel.