I was looking at the original tv-b-gone website and noticed that they are accepting pre-orders for the SHP model. Only 40 bucks for all US and Eroupe codes and its in a PDA case
https://www.tvbgone.com/cfe_tvbg_buy.tv ... f160a0bff5
So how are they getting the 300ft plus and how can we make one?
Anyone know?
Sow how are they making one go 300ft plus?
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More importantly you'll see that the base of the transistors driving the LED's is NOT driven directly by the microcontroller unlike the Adafruit version but instead by using another transistor.
I don't know what the drive capability of the Atmel controller is but likely ~ 25mA. Using the transistor in between it can drive the emitter transistors much much harder.
I don't know what the drive capability of the Atmel controller is but likely ~ 25mA. Using the transistor in between it can drive the emitter transistors much much harder.
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seems to be a zilog z8 variant designed for use in ir applications.
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Is that alot compared to the older version?TheDon125 wrote:I ran it through one of those online LED calculator things, and figuring a fresh 9V and a 0.2V drop across the transistor, there is about 900mA flowing through those LEDs.
Also on a side thought, Could anyone put the schematic into lamings terms. I cannot read schematics at all but just a little and was wondering if someone could bu the actual part number or description for each item.
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Can you post the URL? That calculation doesn't look correct to me.TheDon125 wrote:I ran it through one of those online LED calculator things, and figuring a fresh 9V and a 0.2V drop across the transistor, there is about 900mA flowing through those LEDs.
Here's a link to some calcs done with a similar drive setup (9V being used to switch an IR) with the exception that a darlington was used. Scroll down to the "pulse driving the LED" section.
Dave
Sorry! Looks like I forgot to include the link.
http://www.rentron.com/Fire-Stick-III.htm
Last edited by Probedude on Fri Feb 01, 2008 11:48 am, edited 1 time in total.
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why do you say theres 0.2V across the transistor...? Also have you accounted for internal resistance in the 9V battery?TheDon125 wrote:I ran it through one of those online LED calculator things, and figuring a fresh 9V and a 0.2V drop across the transistor, there is about 900mA flowing through those LEDs.
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When I said the 0.2V across the transistor, I meant the voltage drop caused by the transistor (which looking at the datasheet is more between 0.4V and 0.75V, depending on the current flowing through the transistor). And no, I forgot about the internal resistance of the 9V, so my number is probably very off (the transistor itself is only rated for 600mA max)
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