Reply to thread

Message: <blockquote data-quote="sudu pusa" data-source="post: 12668081" data-attributes="member: 312489"><img src="http://www.instructables.com/files/deriv/FPC/4BP9/RD6EZR7BTBZ/FPC4BP9RD6EZR7BTBZ.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> A little while ago, Makezine blog listed two interesting sites: <a href="http://www.makezine.com/blog/archive/2007/03/how_to_make_a_rusty_nail.html" target="_blank">HOW TO - Make a rusty nail LED night light</a> and <a href="http://www.makezine.com/blog/archive/2007/03/elm_avr_based_radio_spect.html" target="_blank">ELM - AVR based radio spectrum monitor</a>. Chan  has a great site and he has put up a lot of interesting projects,  incidentally many of them based on AVR. One of his projects (not based  on AVR) is a <a href="http://elm-chan.org/works/led1/report_e.html" target="_blank">pocket LED light.</a>  He describes a blocking oscillator based single cell, white LED torch.  This and rusty nail project got me thinking and I started experimenting  with Chan circuit. The circuit is very robust and it worked with a wide  variety of transistors; I tried BC547, 2N2222 and 2n3904. But the  real fun and challenge was in building an enclosure for this torch. I  have been a big fan of matchboxes; as a kid I used to collect empty  matchboxes everywhere I went. I thought the art on matchboxes reflected  the local culture. Long ago, I built a data logger that could  fit in a match box (I never completed it in that form, settling to find a  much larger enclosure). But now I was determined to fit the white LED  torch circuit AND the AA cell in a matchbox. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step1/Build-the-matchbox-tray-with-pieces-of-PCB/" target="_blank">Step 1Build the matchbox tray with pieces of PCB</a> <img src="http://www.instructables.com/files/deriv/FIZ/UXSL/APHEZR7BTDQ/FIZUXSLAPHEZR7BTDQ.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> I  took a fairly large matchbox and threw away the tray and decided to  build my own tray using a technique I had learnt as a radio Ham: to use  pieces of PCB and to solder them together to make a faraday cage of any  size.  I cut three pieces of PCB. I Drilled a large hole to accommodate  the 10mm LED in one of the PCBs.<a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step2/Make-a-cutout-for-the-switch-on-one-of-the-side-wa/" target="_blank">Step 2Make a cutout for the switch on one of the side walls of the tray</a> <img src="http://www.instructables.com/files/deriv/F57/PT1U/THYEZR7BTFU/F57PT1UTHYEZR7BTFU.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" />   On another PCB, I made a cutout for the On/Off switch as seen here. The  body of the switch was bent and soldered to the PCB so that it was  secure. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step3/Another-view-of-the-switch-soldered-on-the-PCB/" target="_blank">Step 3Another view of the switch soldered on the PCB</a> <img src="http://www.instructables.com/files/deriv/F2C/ZE6H/IFKEZR7BTJ3/F2CZE6HIFKEZR7BTJ3.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> Another view of the switch soldered on the PCB. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step4/Solder-the-three-PCB-together/" target="_blank">Step 4Solder the three PCB together</a> <img src="http://www.instructables.com/files/deriv/FCV/ADN1/PFCEZR7BTQX/FCVADN1PFCEZR7BTQX.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> Solder  the three peices together to make the matchbox tray. To solder, start  by applying solder on the edges of the PCBs and then align two pieces  and apply soldering iron. You may need to hold the solder iron for a  little while so that the solder melts nicely. Dont move the PCBs till  the solder has cooled off. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step5/Solder-components-and-add-a-side-wall-to-the-tray/" target="_blank">Step 5Solder components and add a side wall to the tray</a> <img src="http://www.instructables.com/files/deriv/FIY/5IFV/WVBEZR7BTV4/FIY5IFVWVBEZR7BTV4.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> Take  another piece of PCB for the side wall of the tray. I used hobby drill  to create islands of copper on the PCB. Solder the components on the PCB  as per the circuit diagram in the next section. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step6/Circuit-Diagram/" target="_blank">Step 6Circuit Diagram</a> <img src="http://www.instructables.com/files/deriv/F98/7OG1/IWJEZR7BV0J/F987OG1IWJEZR7BV0J.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> This  is the circuit from Chan's website  (<a href="http://elm-chan.org/works/led1/report_e.html" target="_blank">http://elm-chan.org/works/led1/report_e.html</a>) which I modified and  hived off two components. The modified circuit is seen here.  The  circuit is very robust and it worked with a wide variety of transistors;  I tried BC547, 2N2222 and 2n3904. The coil I used had 25 turns each, of  26 gauge wire. Resistor R1 changes the intensity of the light. I tried  values between 2KOhm to 220Ohm and I settled for 220Ohm. The light is  quite bright at this value. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step7/Add-the-final-side-wall-and-fix-the-AA-cell/" target="_blank">Step 7Add the final side wall and fix the 'AA' cell</a> <img src="http://www.instructables.com/files/deriv/FAD/AKQ3/KKOEZR7BV24/FADAKQ3KKOEZR7BV24.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> Finally,  add another PCB for the last side wall. For the cell, I cut a piece of  holding spring from an unused cell holder and soldered it on the left  wall of PCB in the picture and this forms the negative terminal of the  cell. To isolate the positive terminal of the cell, I again cut an  island on the right hand side of the PCB and soldered a wire to the  switch as seen in the picture. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step8/Slide-the-tray-in-the-matchbox-cover/" target="_blank">Step 8Slide the tray in the matchbox cover!</a> <img src="http://www.instructables.com/files/deriv/FYD/WLQ7/15LEZR7BV4I/FYDWLQ715LEZR7BV4I.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> This  completed tray slides in nicely in the matchbox cover. If the tray  doesnt slide in smoothly, file the edges that may be obstructing. <a href="http://www.instructables.com/id/Single-Cell%2c-White-LED-Torch-Fits-in-a-Matchbox/step9/And-switch-it-on/" target="_blank">Step 9And switch it on!</a> <img src="http://www.instructables.com/files/deriv/FML/EAOP/X8CEZR7BV6X/FMLEAOPX8CEZR7BV6X.MEDIUM.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </blockquote>

Verification: Haya warak paha keeyada? (haya wadi kireema paha)

Top Bottom