#1
Santi
HP MCE Blaster learning code problem solved - LM bug? + expanding distance of the IR blaster
Hi all. I bought fine HP remote (MCE compatibile). I wanted it to simply control some applications on common Windows XP professional SP3 (not the XP Media Center Edition 2005). The remote started working right without problems, however I have got some troubles with the IR blaster bug. First, the LM got problems to recognize the MCE IR Blaster. It writes unavailable. I have tried cca three versions of original Microsoft MCE driver and finally I have got the blaster working.However the main problem become with starting learning codes from any common remote (tv, sat, etc.). The first code learns fine, the second one also. Then when I push the "try" button, IR blaster start blinking but the TV do not receive the code.
After some searching, I found out that shown code in LM learning windows is such -1|1440 -650...etc. The first number should be frequency in Hz, but it was learned as -1 !!! When I manually rewrite the -1 to 40000 (common IR beam is something between 38-40KHz) the TV started to receiving the code.
I just dont understand why the learning process recognize code as -1 frequency. I think it is kind of bug of LM itself and hope the developers will repair it. Or Im doing something bad that I got the -1 instead of frequency?
Moreover, I found the IR blaster works only for few cm from TV receiver. I would like the blaster working like common IR remote and control the TV from distance of cca 4 meters. Has anybody try yet to rebuild the bug for such distance? I think one IR diode + NPN transistor and two resistors plugged instead of blaster and powered directly from USB may do the work. It should be able to push full power of the USB through the IR diode (100mA..5W) in pulse mode. Even more, from one USB port three IR diodes can be supplied (common IR diode needs 1.3V) to make the signal stronger. Nobody tried it yet?
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#2
StephaneMRe: HP MCE Blaster learning code problem solved - LM bug?
I just dont understand why the learning process recognize code as -1 frequency. I think it is kind of bug of LM itself and hope the developers will repair it. Or Im doing something bad that I got the -1 instead of frequency?
The "-1" means that the receiver wasn't able to detect the frequency. Maybe because you keep the original remote button pressed too much longer.the IR blaster works only for few cm from TV receiver. I would like the blaster working like common IR remote and control the TV from distance of cca 4 meters.
This is how it is supposed to work. I don't know if you can mod it to suit your need (The USB-UIRT internal port is able to blast from long distance, I don't know if it can blast over 4 meters however.)Regards,
Stéphane
#3
Santi
Re: HP MCE Blaster learning code problem solved - LM bug?
The "-1" means that the receiver wasn't able to detect the frequency. Maybe because you keep the original remote button pressed too much longer.
Believe me, I tried to press it very quickly, slowly,.. try different kinds of remotes. Still the same problem. Maybe it is HW problem of the HP receiver, but I would beg for the problem with LM Remote itself.
This is how it is supposed to work. I don't know if you can mod it to suit your need (The USB-UIRT internal port is able to blast from long distance, I don't know if it can blast over 4 meters however.)
I figure out how to prolong the distance. Original IR blaster is just 3mm IR LED diode + cable with jack connector. I opened the receiver and looked inside how the circuit is done. And really, the IR LED blaster is driven by one transistor and 100R resistor directly to 5V from USB. It means, that through the IR LED is going 30mA current. It is really not much, common remotes use something like 100mA till 1000mA, plus they offten double the diodes for even higher power.
At first, I tried to use bigger IR diode (5mm) which has higher gain. Just by changing IR diode, I was able to prolong the distance from cca 5cm to cca 1m. Not, bad. Today I will try to higher the current from 30mA to 100mA (maximum the USB can offer without negotiation) by changing the resistor from 100R to 36R. And maybe, if the distance would be not enough, I will use two IR diodes (two IR diodes in series + 22R resistor - you may even use three IR diodes in series + 8R2 resistor.) I think the result will exceed the needed 4 meters. I let you know about the results.
UPDATE: Ok, so I have tried to give IR diode more power. By putting 100mA Im able to control TV from 4 meters. However, I can control it only if the diode is directly aimed on the TV reciever. This may be due to used IR diode, which is common 5mm IR diode 8-20mW/sr 30deg. I will try more specialized diode for remotes, such as LD271, LD274, HSDL - 4220 or IR850 80mW/30°. All of them should give more power so I think the IR blaster should start working as common remote and will operate also by reflection from walls. (It is main idea, have a HTPC under plasma TV and operate TV through reflection from a wall.)
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#4
StephaneMRe: HP MCE Blaster learning code problem solved - LM bug?
Believe me, I tried to press it very quickly, slowly,.. try different kinds of remotes. Still the same problem. Maybe it is HW problem of the HP receiver, but I would beg for the problem with LM Remote itself.
The receiver is sending the remote carrier frequencyStéphane
#5
Santi
Re: HP MCE Blaster learning code problem solved - LM bug?
The receiver is sending the remote carrier frequency
Does it mean the receiver should send the remote carrier frequency, but they may exist receivers, that do not provide this information and send just code itself? Why not to program the LM Remote, if not frequency available and code available do not write -1, but put some default frequency for example 40KHz? It may solve problems to users that may experience same difficulties. (I agree, it may generate some other problems, but to much lower number of users than not putting the frequency into code). message edited on