Hi guys, as you know recently finished my second TJ07 build.
One thing thats annoying me though is the inflexibility of some of the electronics I built into it, such as my LCD displays are fixed to do one thing, I have a separate USB interface mounted inside that controls LED lighting etc now I think i mentioned this before but it got me thinking that I could probably do a better job than the off-the-shelf stuff that Ive got in there regarding the USB interface.....To coin a Jeremy Clarkson phrase....How hard could it be?
So I decided to start a project thread for this little add-on project of mine to show how its coming along, think its gonna take me a fair while as i didnt realise the complexity of this before I jumped in at the deep-end. I thought it might be an interesting read for people on here since this is some damn complex and a one-off mod.
Broken down this is the wishlist:
- Be able to PWM control fans from PC software (2 groups of 2 fans)
- Be able to interface and measure multiple temperature sensors in PC software
- Control around 5 or 6 12V supplies for lighting etc
- Be able to sense a few switches into software
- Fully control a 16x2 or 20x4 LCD display with messages sent from PC software and backlighting and possibly contrast.
- Oh and did I mention its all gotta be small enough to go in a 3 1/2" bay
Nice little wishlist I've put together I think. Now its gonna be a test to see wether I can actually do it...or not.
Since things are always better with pictures this is the microcontroller I selected for it:
See i said its gonna be small, Imagine all the swearwords that will be streaming from my gob when I try and solder that thing in. However it does pretty much everything on my wishlist, built-in USB USART for comms to/from PC, around 20ish multi-purpose IO, analog inputs for temperature sensors, 2 channel PWM for controlling fans and best of all it only costs around £5-6.
Here's a basic prototype for now
That huge 40 pin chip is exactly the same chip as the small one, just a bit easier to work with on a prototype plus easy to replace if/when the magical black smoke appears
Ignore all the stuff on the left, just leftovers I havnt stored away yet. It will need quite a few external components, MOSFETs for controlling lighting and for PWM control of fans, filtering for temperature probe inputs etc however I plan to use SMD devices for this so as to keep everything tiny.
Anyways thats the progress for today, more to follow soon I hope. For the rest of today I shall be learning C for writing the firmware and C# for the PC side of things and trying to get the chip and PC to talk over a USB cable.