Hi all, just thought I'd post this little design I've been working on over the last couple of days. I'm going to put together a PC that is silent as possible around X-Mas time, and so would like to have control over the noise relative to load. I've made a couple of PWM controllers using the MIC502, but I didn't want to have analogue control like it offers in the Bit-Tech design, as I'd be adjusting it constantly. So, I present my solution: It's effectively cpemma's Pulse Width Modulation Thermal controller with the diode clamp and tweakable thermistor settings. However, I added the 4017 at the top to switch the position usually taken by the thermistor, giving me four options which can be set by changing the resistor in each respective position, one of which for me would be a thermistor. I'd set the other three resistors to give Full On, 6V, and off. The other addition is the tri-colour LED to indicate the state; when 12V it is one colour, 6V the other, and at Auto (ie, temperature controlled), it's the combination of the two. The PCB shown is 56mm x 57mm so is nice and small, and I can probably get it smaller as well. It's single layer with only 3 jumpers, and two of those can be removed easily. I would usually make it SMD, but I thought if others wanted to build it, that wouldn't be sensible. The output transistor is a BD140, but the Eagle libary wanted it horizontal to the board, so it appears as a TO220 package. I was thinking of getting PCBs made for it, so if anyone would be interested just let me know. That's not certain though... Schematic on request, will post publically enjoy g
What did you use to do that drawing? and what did you use to design the board? it's sexy Schematic too
That's Eagle 3D - a plug in for Cadsoft's Eagle PCB software. Here's a pic of a little circuit I'm deisgning at the moment, done using the same software. It's not quite finished. Link Nice circuit. I was thinking of building one myself, but have never got round to it. I'd say definitely go for it, and get some PCBs made - it looks like a fabulous kit for beginners to start with.
Well, if I got 25 PCBs printed professionally, they'd come to about £3.10 each plus postage. Component cost is only about £5 or so, so total cost would be around £9 or so per control channel g
I'm still interested, but my concern would be with cost - shipping would probably be pretty expensive to Canada, but I would buy more than 1. I'm sure you could sell lots of them easily right in the FS forums, as people are always asking where to buy fan controllers, how to build their own, etc.
Shipping is pennies to North America, that's not really an issue. I'm not going to need it until december, so I'll look into getting them done, especially as Christmas will be coming up then. I'll keep everyone posted
