The movie shows v1.1 of the firmwire in action. Tomorow I’ll be ordering the pcbs and parts.. The final version will use bargraph LED’s for the display and it will be composed from 2 boards, the motherbord containing most of the parts and the LED board containing only the bargraphs.
In response to the high interest shown by the readers on a spectrum analyzer posted here I decided to make a new design, that will be available in shop as a kit. The movie shows just a stage in the developing process, where the filters were being tuned. The final design will be powered by an atmega64 and will have 20 bands with 20 LED’s on each band.
I am now searching for a pcb manufacturer to get a good price on manufacturing the boards, then it will all be ready.. stay tuned.
I liked the tvbgone kit from Ladyada the first time i saw it but i never had the time to build it, until a week ago. But than i decided to build a more powerful one that could turn off TV’s from even greater distance. I came up with a design that consists of 48 IR LED’s and a ATmega8 that will send the signals to the LED’s.
the led board
Unfortunately i wasn’t paying attention on a small paragraph from Ladyada that was saying “Use 940nm IR LEDs.” so without knowing i bought 860nm IR LED’s (L53SF6C from Kingbright). I did not knew at that time that this is going to affect the distance at which the device works. Why L53SF6C ? they seemed nice because at 50 mA they have typical 100 mW/sr so allot more power than the F3(940 nm) series which had 30 mW/sr at 50 mA.
I arranged the LED’s in 4 rows of 12 pieces and the resistors fit quite nicely between the LED’s. I used four BD139 NPN transistors to drive the rows. It took me hours to drill and then solder this board(48 LED’s and 48 resistors mean 192 holes plus the other parts)
the controller board
The controller board contains an ATmega8 chosen because of it’s 8k memory needed to store all the codes, an 8 MHz crystal, an LED, a tact switch and some resistors and capacitors. I designed the board so that it can also be used for other projects.
the code
It took me some time to adjust the code from tiny85 to ATmega8, getting the timers right was tricky but i managed to get it done. Also i had to delete a couple of codes to fit it in the 8k’s of the ATmega8.
the power
The whole project is powered from a Nokia BL-5B battery which was ugly fitted onto a peace of PCB 
. I can’t seem to find a decent socket to hold such a battery. I’ve run the circuit for over a week every day and the battery is keeping up, and when it gets discharged I’ll simply charge it inside of an old nokia phone.
Testing it
Well as you can imagine the first thing i did was to test it on the TV’s in my place, it worked perfectly. Next i wanted to test it on a larger scale so i took the device onto a nearby supermarket were they have a bunch of Tv’s onto a wall. I had to conceal the device somehow so they don’t kick me out of the store so i placed the device inside a CD case. I don’t know how much the case is obstructing the signal, but it was turning off TV’s from a distance of 20 meters.
Probably choosing the right wavelength LED’s would double the distance, and by using a clear case the distance would double again, but that’s just a guess.
The boards were designed in Eagle and fabricated by me using the photo etching technique.
I’m planing to build a newer version, in fact i already sent the files for PCB fabricating. This new version will use only 4 LED’s just like the original design, and will be smaller thus easier to conceal and it will also use ATmega8 for the controller. I’ll post pictures as soon as i get it done.
some more pictures..
downloads
This article is part of the PCB Giveaway program that we have running here at Youritronics. Morgoth will get a free pcb manufactured by BKRtech for submitting this project. If you’re interested in participating, read more on the program page.
These days most pharmacies use LED pharmacy crosses posted at their entrance to let people know there is a pharmacy there. The reasons are obvious, they look cool&hi-tech, they can be seen from distance and they can be customized really easy (well, easy customizing pretty much depends on how the manufacturer approaches things).
If you try to search the web about schematics or example codes for this kind of circuit you wont find any, and again i think the reason is obvious, the crosses are quite expensive and so is the profit for the manufacturer. So nobody is gonna post schematics for such a project, unless you’re a hobbyist and you’re having fun with electronics.
The project consists of one ATmega64, three ULN2003 and five 5×7 LED matrix from Kingbright(TA20-11EWA). I had the idea to build something like this but so far i haven’t had the time nor the knowledge to get it done. So i asked Morgoth if he would like to participate in the project. I sent him the LED’s, the drivers and the PCB and he started working. As you can see not many parts are involved , but the secret lies in the microcontroller, it’s the programming that does the job.
In the next pictures you can see the microcontroller board with the ULN2003 darlington arrays:
The circuit was designed to receive messages trough serial interface from a computer and than display them. Morgoth also designed a custom terminal for windows which provides easy access to the display.
In this test phase a serial interface by wire was used to transmit data between the terminal and the ATmega64, but a wireless or bluetooth module could be integrated with no problem.
Also as a note, the LED’s don’t light up really bright, for that to happen you need to use drivers on the positive rail. This also applies if you’re planning to take the project to another level and use bigger LED’s
And now, watch some videos with the LED Pharmacy Cross beeing controlled from the computer:
The Gas Guzzler Meter is an attempt at putting an immediate dollar value on your current driving techniques: a digital meter that displays exactly what you’re spending as you motor along. Stomp on the pedal and see the bucks zoom out your tailpipe faster than a NASCAR driver competing for the Nextel Cup. This device will help you impress your friends, drive responsibly, and keep those dollars in your pocket.
Gas Guzzler Meter: [Link]
