I got a frigid greetings by email from Kirk, where it’s a bone-chilling -20 deg. F in Winnepeg, CA. \u00a0 He’s building a similar device to find a misplaced object.\u00a0 I have a few other Ideas I’d like to go over.<\/p>\n
The Blue Blinky uses a Joule Thief circuit, which works with any color LED because it can overcome the 3 or more volts that white or blue LEDs require.\u00a0 However if you can use some color other than blue or white, there are other circuits that might work well.<\/p>\n
The Blue Blinky consists of two parts: a Joule Thief and a flasher which turns the JT on very briefly.\u00a0 This flasher is capable of flashing a LED by itself if the supply voltage is greater than the LED’s forward voltage.\u00a0 So if the supply voltage is two 1.5V cells in series or a single 3V coin cell, the flasher circuit alone should run most colors other than blue and white.\u00a0 Some green LEDs require up to 3V, so they may have to be tested beforehand.<\/p>\n
The TE Flasher<\/strong><\/p>\n Now, the above flasher uses a supply voltage of 3V, and works okay with most lower voltage LEDs.\u00a0 But say I want to use a lower voltage LED with 1.5V cell.\u00a0 How do I increase the voltage up to 2 or more volts to light the LED?\u00a0 The Joule Thief is an easy way to do this.\u00a0 But there is another way, without a coil or transformer.\u00a0 This is by charging a capacitor across the 1.5V cell,\u00a0 then connecting it in series with the 1.5V cell to give 3V.\u00a0 This is what I did with the TE flasher<\/strong><\/a>.\u00a0 The schematic shows the 100 uF capacitor.\u00a0 When the BC327 turns on, it puts this capacitor in series with the 1.5V, so up to 3V is across the LED.<\/p>\n I have also built a few of the Blinky Boost flasher<\/strong><\/a> that uses two capacitors, so it can put out over 4V to the LED.\u00a0 This is even more complex than a Joule Thief, but it seems to use less power and the battery seems to last longer.\u00a0 However every Joule Thief can be modified to use less current, but no one has explored this method in depth, so Blue Blinky type flashers that use a JT having low current are not often found.\u00a0 One point has to be remembered: a Joule Thief has a typical efficiency of 50%, which means you get less light for a given supply current, or you need more supply current to get the same amount of light.<\/p>\n A couple things about the Blue Blinky<\/strong><\/p>\n I used two 680k resistors because they were easier to find than a single 1.3 Meg resistor.\u00a0 Also I figured that I might like to put a 1 meg resistor in one place on the circuit board, and a 470k trimpot in the other location.\u00a0 That way, I could adjust the flash rate somewhat.<\/p>\n Also, the 68k resistor determines the flash length.\u00a0 The smaller its value, the shorter the flash duration. A longer flash uses more current.\u00a0 The .01 uF capacitor could be any value down to .001 uF and it shouldn’t make much difference.<\/p>\n Capt. Hook’s Ticking Sound<\/strong><\/p>\n Another thing I’d like to go over is the use of sound to locate the remote control.\u00a0 If I connect a receiver out of a telephone handset between the\u00a0 LED and negative, it gives a clicking noise.\u00a0 The high voltage that could be generated by the inductance of the receiver’s coil can be damped by putting a resistor across the receiver.\u00a0 This also lets me control the volume, so that the remote doesn’t become an annoyance when it’s near.\u00a0 The receiver could be too big, so another possible ‘speaker’ that could be connected in series with the LED is an ear bud.\u00a0 They are small, but they are typically low impedance, around 16 to 32 ohms.\u00a0 I haven’t tried this yet, so it’s something I’ll have to experiment with later.<\/p>\n","protected":false},"excerpt":{"rendered":" I got a frigid greetings by email from Kirk, where it’s a bone-chilling -20 deg. F in Winnepeg, CA. \u00a0 He’s building a similar device to find a misplaced object.\u00a0 I have a few other Ideas I’d like to go over. The Blue Blinky uses a Joule Thief circuit, which works with any color LED <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[142,4],"tags":[],"class_list":["post-8965","post","type-post","status-publish","format-standard","hentry","category-flashers-and-attention-getters","category-joule-thief-smps-dc-dc"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/8965","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8965"}],"version-history":[{"count":21,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/8965\/revisions"}],"predecessor-version":[{"id":8968,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/8965\/revisions\/8968"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8965"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8965"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8965"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}