I'm thinking of this as my eastern project, and my very first mod too. It'll be to get my noob skillz in soldering and stuff a bit higher, so I can start creating PCI cards (lol). Anyway, this is what I was thinking of: Using this one as the sender: It's a 433Mhz transmitter, and it's capable of sending with a speed of 2.4kbps, ideal for an MO LCD, don't you think? (2400 or even 1200 are supported by the LK204-25PC, the one that I'm planning to use). So, how do I do this? I was thinking of directly connecting pin 3 of the com port to pin 6 of the transmitter, and using the 5 volt of a molex somewhere at pin 1 and 2, and adding ground to pin 3 and 4 (pretty straightforward, don't you think ). This is a pic of the com stuff, taken from the MO site: For the receiver, I'd use this one, it's made for the sender I'd use: So, pin 1, 6 and 7 to ground of battery or adapter, pin 4 and 5 to 5 volt of battery or adapter, pin 8 the antenna, and where do I attach the pin 3 of the LCD too? Digital or linear? What's linear (appart from a really cool guy of the USA )? And will I have to use a resistor of some sort? Here's some more info about the pair: http://www.rentron.com/rf_remote_control.htm I think I'm gonna order one of the antennas they have (look in the remote control store) for the LCD, and get a nice looking box somewhere to put it all in. Still worrying about the battery though, how long will it live on 1 (or 2 or 3 ... ) batteries? If anyone can be of any assistance, I'd greatly appreciate it, and I just wanna know for sure this is going to work before I order this stuff...
OK, you have a winner, I believe. You can ignore yhe analog output from the receiver, it's just there to make the tx/rx pair more useful as general purpose devices. I didn't get a real good sense of what you want to do, but here's a couple observations: If you just are sending data to your LCD, no receiving of keypad presses, then I think you are in great shape. Just wire these puppies up like the datasheet. Even if you want to read from the keypad, these look like they should be transparent to everything concerned, but I can't comment on how the software maight react to having this in the loop. If you were going for a remote control for a car peecee, you may want to spend some time with a software guy (hey--you are one!) looking at the timing implications of reading the keypad, and whether the software uses the buffer on the keypad etc. etc.
Oh, and I forgot about battery life. That will be tougher to manage. You'd need to determine a way for this thing to 'sleep' and wake up, so I think you're pretty much hosed on battery life. Buy some rechargeables.
hehe, thanks man, you're the only one that replied on this one, I greatly appreciate it, thanks! Okay, so no need for resistors or anything, right? Yeah, just sending info to the LCD. Might do the feedback later when I have more money What do you mean by "transparent to everything" ? And no, no car peecee stuff, just a way to show off I have skillz (I don't have skillz, but who knows? ) to my friends, like: Hey pieter, oh, let's check what my PC writes on the LCD ... (takes the LCD out of pocket) ooooooh, it's now 21:30! Who would've thougth that??? (slaps hand against cheek) lol I'm going to order this stuff now, thanks for the help!
By transparent I mean that the system behaves as if the serial link were wired. I don't know the details of interfacing because I took no more than a quick blast through the link you gave, but the example that used a basic stamp looked very close to what you should be doing.
errrr....changed my mind...I really don't wanna pay $42 for shipping only, a total of $66 for a $24 worth of materials ... goddamn why don't I live in the USA... I'm gonna do a search for a European distributor. If anyone knows of any, please post here!
rapid do em it will cost 25 quid for a pair with a data rate of 1200bps by the looks of things 43-0344 is the transmitter and 43-0346 is the reciever but someone else might want to say if this is suitable im not sure when it comes to radio stuff :-/
rapid?? but I already found a UK distributor for the same chips, £10 for the transmitter and the receiver together, £7,50 for the shipping and insurance, and 17.50% VAT, which comes down to a bit more than £20 total costs: http://www.picbasic.co.uk/item31.htm
Looks like a good idea! Just make sure there are no wireless devices (like wireless keyboards, or TVs) around when you test it Signing out...
Looks like a really sharp plan! Only consideration i can think of would be the realistic location for the antennas on the xmitr and rcvr. It'd be a shame not to have the antenna not tuned properly and overheat/smoke the xmitr. No harm to the rcvr if its too far out of tune it just won't be able to hear the RF as well. If my ham radio memories serve me correct you can use 468 / freq. in Mhz = ant length in feet. (then convert to something more useable) This should give you a reasonable length for a 1/2 wave ant. I'd suppose a UHF SWR bridge would come in handy here for anything exceeing a 100mw or so, But i didn't see anyting on the spec sheet about how much RF out that little xmtr puts out...
I'll have to save this thread in my mod ideas folder, it would be of use even if you were mounting your LCD internaly!! Kool idea!
Faith, I have plenty, thanks. I am just worried that the neighbors might get anoyed at their TV changing chanel every time your LCD screen refreshes Post pics after you're done, this is one LCD mod I've got to see! Will it be bl00? Signing out...
the page sais this is an apropriate antenna: http://www.rentron.com/remote_control/434-RF-Antenna.htm and a wire of 30 - 35cm is ok too they say on this one: http://www.rentron.com/remote_control/TWS-8-bit-pack.htm so, as I don't know much about RF, I just buy something that looks like the first one with the same specs and stuff. what's a UHF SWR bridge? And thanks for your info, I didn't know the wrong antenna could blow the chip
An SWR Bridge is what we use to match an antenna to a transciever. Very basic RF lesson SWR = Standing Wave Ratio, it measures the standing wave(s) on the antenna at given freqencies... a perfect match would be 1:1 meaning the ant is tuned exactly to the freq. the xmitter is xmitting looking like this sine wave when the wave ends perfectly at the end of the antenna (the line in the middle) it is perfect (theorectically) any the left over of the sine wave would be considered a Standing Wave and would be reflected back down the ant. to the xmitter which results in decreased efficiency of the 'finals' and produces heat. Hope this makes sense, It's been a long time since learning this stuff, so its just something i know but to try to explain it...well that's something else Hope this helps..... Dakar
Using the formaula 486 / 433.99 = 1.1198 ft x 12 = 13.43 inches or about 34cm (taken off a measuring stick...can't remember the conversion formula) So its within the boundaries they quoted, but now you have an idea of where optimum performance will result. But keep in mind this works for an ant. that is relatively straight, if it was coiled up at any point you will add capacitance to the ant. and this will change its effective length/performance as well... and keep the ant lead insulated from touching things like the metal case! No sense applying more RF to your puter, I'd suggest routing the ant outside the case if possible. Wow this thread is fairly technical A couple more like this that i can actually relate to and I'll earn an avatar... Dakar
