how can i dim a cold cathode and led's (seperate circuits probably) from being fully on to off. possibly using a series of pulses. if possible i would like it to be a smooth dim over 5-10 seconds a stepped dim would look wierd. Snood
Cathodes are very bad for dimming, and you can't dim them off, they start to flicker very badly. As for an LED dimming circuit: This will dim an LED on and off at a speed variable by VR1.
does this constandly dim up and down, i want something that will dimm down, then come back up again at a later time. so i dont want a constant cycle Snood
can anyone modify the above circuit......acrim... you made it.. can you help? i want to be able to to the following with it.. fade the leds on fade them off (not constantly) be able to make them flicker or perhaps more accuratley apear to shimmer. and i want to be able to control this using the output of a pic or a Basic Stamp Snood
Do you want a shimmer for a fire effect? If you are going to use a Basic Stamp use the PWM output, with a RANDOM time interval. I tried this to simulate fire using four different colored LEDs The results were very nice.
well i hope to build in different modes.... like fire...and other shimmering effects using different colours delays etc... can i also have it steady on instaed of pwm?? (for full on lighting) and how many pmw. the problem i face is that basic stamps can only actually perform one task at a time.. however if i have the basic stamp doing the fire effect... then how do i get it to controll my case fans?? (i am going to use it to turn motorised pots) talking about that zap.... is it possible for the basic stamp to tell what level the fans are set to.. for example... it knows if its at 50% power or something. ................. i dont fancy using pmw to control the fans because ive heard it doesnt do the fans any good......plus it means i cant have the rheos apearing to turn all by themselves.. Snood Thanx zap
If it helps the AtomPRO from www.BasicMicro.com is only $29.99 It has Hardware based PWM features, meaning you can set-and-forget. Now this would not provide for a constant variance, but at least you can set it to a certain level and continue with other stuff. Plus it has mutiple servo control,
ok zap but dont motorised pots work on motors not servos.. i thought it was a bi directional motor with a gearing system so that even if you try to electronicly turn it to far, it just sits there with the motor turning nothing. Snood while i still have your attention zap: this whole led and pot thing is a part of my light and fan controller idea. i was just wondering if it is feasable to do all of the followinf with one basic stamp and other electronic parts: 1) turn fans on (with some sort of 12v starter to guarantee they start) 2)Turn the fans up and down manualy (easily done. all you need is a hand) 3)turn them up and down automaticaly. say to "quiet mode" for DVD's or "high performance mode for games. etc... and anyway if interfacing it with the computer so it knows if a dvd is playing or if i am playing perticular games. idealy i would like to actually specify a power level. if it helps. the pots i am using are dual 10k pots. (all electronics) 4) controll my lighting. user defined animated lighting paterns or just on, or dim, orr off for dvd's (again interfacable if possible) thanx zap if you can help... and if you cant help... also thanks... ure a legend Snood
Sry, I must have missed the post. I was just mentioning the multiple servo control. (No, it wont work on normal motors) 1)The fan control is easy enough, for the burst of power, a simple capacitor would work just fine. Or if you PWM control the fans, just make sure they get a 100% burst at the start. 2)Again the PWM is easy to use, and you can set it to anything you wish 3)This can all be done via software and the PWM. I was going to do this for my Media PC (PWM control the fans) But my system is ending up quiet enough so far. But I am doing the same for the LEDs They will change modes depending on what the PC is doing. (Controlled over the serial port) 4)All similar to the above techniques. The AtomPro has three Hardware PWM controls. These are set-and-forget. (CPU power is not needed) One value, which you can change of course. But for pulsing effect and such, you need to use the software Pulse width modulation, but this takes up CPU time.
if i PMW the fans i wont be able to have self moving pots. i am planning to base it on the first circuit on This Page. using a motorised dual 10k pot from all electronics to automaticaly turn the pot. is there a way for the basic stamp to find out exactly what position the pot is in so it can make changes acordingly?? Snood
Sure just have the stamp read the value of the POT, you can then use that to figure out the pots current position. Also the Servo control is stated in the manual as using a type of Pulse Width Modulation. So it may work on normal motors ,via a transistor or two. (I am not sure) You can use one of the Hardware PWM for the Motorized Pot That leaves you two for what ever you wish. You can run more than one fan per transistor (Connected to one hPWM output)
i'm thinking about using the Basic Stamp in conjunction with PIC08 microcontrolers to enable me to perforrm changes to more than one fan channel simultaneously. i'll be spending my summer holidays prototyping, then building the circuit on a pcb when i get back to school (schools developing, etching facilities) thanx zap.... i hope i will be able to come to you for more help if i need it during the prototyping stages Snood
