trigger

Ante, I am using XP professional SP1. Problem..... already solved by reinstallation. But really, if XP are in trouble, it is very painful to recover it. I do agree WIN2000 is very good and stable.... However I think most stable one will be DOS6.22 + Windows 3.1 era..... :P

XP doesn't have a startup floppy....... but I can bootup XP installation using CDROM

the marking on the battery is showing mAH, i.e. milli-ampere hour. By dividing it with the current drawn by the unit, you can guess how much hour your unit can use (for the battery is fully charged) So it needed not a supply to give out 800mA for your application. Just a simple regulator circuit will do.

PCBExpress and PCB123 aren't that free as the only way to get PCB or gerber file is to pay them.... Eagle is good, but I just play with it a little bit. Can't give much comment to it.

Ante, noope, I am not giving up. For example, recently, my computer (windows XP) mess up with some dll file corrupted. Even I try to perform a system restore or start on a safe mode can't success.... i.e. can't bootup windows.... thus my way is to reinstall it..... without another choice. of course if I am not lazy I can have a backup using Norton Ghost.... :P

may be a light chaser can have some fun 8)

The final solution of windows trouble is to format and reinstall it.....

if it is just a sound activate door opener, then you can use a relay and a electronic lock and a sound activate circuit. However, if you want to have voice recognition, it will be a much more difficult one. It will be another issue. Most likely, you need a fast processor or even a PC to do so.....

Here is the draft circuit diagram of the repeller I have. Hmm.... it just buzz.... and I heard the sound....... :P I can't guarantee it works on repel mosquitoes...... it is just for fun only..... and I haven't rebuild one myself...... The NPN transistors are SMT components which marked L6, I haven't check its part number but I believe it is from On's Semi. The coupling capacitor C is 1000pF where I haven't put its value in the schematic... And the switch is for select high or low buzzing frequency.... So if any of you have build it and test with a mosquitoe, then let us all know about its performance. 8)

In case you know chinese you can try this link to search http://www.hqew.com/document/

Hey Dido You have very good equipment for playing with chemical..... ;) For me, I only use plastic box to etch my PCB at home.... :-[ At office, there is a tank of etching solution, but it is slow and dirty........

I hear someone using concentrated Sulphuric Acid to have fast etching of PCB . Personally I haven't try because it is very corrosive.... very danger for diy..... so I prefer to wait for 15 minutes :P

You are welcome. I just found the site yesterday where some of the circuits inside are useful to me too ;D

You can also check this link in case you are sure the grounding is ok. http://members.shaw.ca/roma/nine.html

Check this link for some useful circuit http://members.shaw.ca/roma/seventeen.html

hmmm...... such hum may cause by poor DC grounding or the tuner circuit problem. Can't give you much suggestion by now unless we have a chance to look at the circuit or PCB baord.

It is a nice idea but the copper wire will stick with solder and may mess up your work...... My experience is to use sharp solder iron (25W is fine) + thin solder (0.6mm) + tweezer + solder paste , then everything will be nice. But somehow beware of the solder stick to adjacent components' pads.

I think it may be an 0402 size component. The soldering method is the same as other size but suggested to use a sharper solder iron to do so.

hmm......... you can use tone detector IC (LM567 ) after reciever for such application which will lower the complexity of building the comparator. I haven't build circuits with this IC but I do think it may fit your needs.

Very nice site!! Good!!! May try some later for fun :P

Try to get more solder on the pads and use solder iron to melt. After a several seconds, you can easily pull components out. That is what I do in the factory.

As I am in Hong Kong, I think most of the IC manufacturers will forward the sample order to the distributors in Hong Kong......... and I do think most of them are not willing to send samples especially we are for our own usage.... :-\ I haven't give an order yet.....hmm....... may be I should try Microchip first....... ;)

Thanks for reply. I can tell you that I am currently working on digital tuning system, that is, a PLL+VCO. However, it is quite different from that of manual tuning using capacitor, esp. matching RF coil part. I know that for radio sensitivity, mostly it related to circuit layout and component placement.... but I just hope to find an effective way to reduce the trial-and-error time. ::)

higher frequency will have more interference esp. 2.4GHz band...... like microwave oven, DECT phone, wireless lan, Bluetooth etc. For 433MHz, I think if you are in UK, the most problem will be caused by the TETRA (police RF communication ?? not sure, it is at 426MHz). You have to build a narrow band receiver to prevent jamming from it.

There is no easy way to place components, it really depends upon experience and some restrictions towards mechanical and/or electrical issues. I will use alignment tools in the CAD to make the components placement looks more tidy......... that is what I do...