aggreedOriginally Posted by evandude
aggreedOriginally Posted by evandude
I'd love to get one, when can we expect to see one?
Evandude and dragonBTV,
Here is the info for you.
My design is based on a Picaxe18 chip. (www.picaxe.co.uk)
The reason I decided on this chip is
1. It's quite easy to get a working design quickly even tho there are some minor limitations on what the chip can do.
2. It can be programmed with a serial or USB.
3. It can be programmed on the fly and in circuit. If you want to change the parameters while your PC is on, you can.
4. The chips are quite easy to get hold of. They are a little more expensive than a pic chip but as I said are easier to deal with and you don't need to buy a programmer to change the code.
I'm sure that there are other microcontroller chips that can be used, but I found this was the easiest way to get what I wanted with a lot of flexibility.
At the moment I have inputs for :
Switched Ignition (state of the car - ign switched on or off)
PC power (PC on or off)
Shutdown state (selectable time for shutdown and any faults or low battery)
Main power (power to the system)
ATX pulse (pulse to the power switch on the mobo the turn PC on)
Aux on (programmable delay for turning on amps, etc)
Screen on (programmable delay for turning on monitor)
LED output (using a tri-colour LED to show status of the system. Power on, shutdown or fault state)
All these inputs and outputs can be switched on or off depending on user preference. Timing for aux and monitor power can be changed to suit user preference.
I have the code pretty much sorted out, it just needs some fine tuning. Once the code is tuned and optimised, I was going to write an interface program so the varaibles could be modified from the PC when it is on.
The board shouldn't be any larger then 2"x3" when finished depending on layout.
Let me know what you think.
Never let the truth get in the way of a good story
I will focus on PSU itself
Evandude will focus on a reprogramable SDC
and if you like, you can share on designing a low cost SDC otherwise I am going to design a very simple anlogle SDC on it as default.
Q:why are you going to design a 300W PSU for carpcs?
A:according to the needs of carpc lovers, 150W in total could not meet the needs on both the CPU and car accesses, because they either need 12V or 5V and you can not sharn the power of them sometimes. what we need is a PSU which is strong on +12V, +5V and +5VSB(for more and more USB devices which you would added)
Q:is it difficult to design a 300W PSU than a 150W one?
A:Yes! much more difficult. that is why you can not find 300W class productions easyly world wide now. even the famous IC producer like NS,LT,IR,MAXIM does not have the related chip solutions...
in order to meet the needs of +12V, I have to either switch up from 8V or switch down to 18V. the input current sometimes over 30A and I have to keep the effitioncy as high as possible (above 80%), have to say, it is really really a hard job!
I could not solve those problems before I invent this "smart boost" design and use current sharing technolegy together. this picture is the DIP version "smart boost" +12V PWM control board, and there will be two of this board on the 300W PSU (of cause the product will use SMT version)
you can find out there are 6 chipes and most of the rizistors on the back...
and it is one of the two CONTROL boards of +12V ONLY!
Q: will this 300W PSU very expensive?
A:No! the aim of this design is to make a stable and low cost PSU for carpc users. I am sure it will be called "tiny and cheap"
Q: who are you and where are you?
A: I am an well known host and producer of Beijing TV station of People's Republic of China, and I am 40.
although my job is a TV producer, I started to be a radio fan since 15 and my major in university is radio and electronics too....
Q: will this 300W PSU be a free project or will you sell the kit?
A: I am sure not. because it is not easy to get the ICs from free sample ordering and it is hard to DIY such full SMT kit.
I hope MP3CAR store will host the finished product as holeseller at last.