1 00:00:00,080 --> 00:00:01,490 Well, it’s been a minute. 2 00:00:01,490 --> 00:00:03,598 I’ve been working on a pretty complex topic, 3 00:00:03,598 --> 00:00:06,540 and in the meantime I need to think of something quick. 4 00:00:06,540 --> 00:00:09,012 If only I had more time… 5 00:00:09,012 --> 00:00:10,287 that’s it! 6 00:00:10,287 --> 00:00:13,271 How ‘bout a little taste of November in January? 7 00:00:13,271 --> 00:00:17,166 Do you have an electrical thing you want to have turn on at a specific time every day 8 00:00:17,166 --> 00:00:20,691 and then also turn off at a specific time every day? 9 00:00:20,691 --> 00:00:22,999 I know, so do I! 10 00:00:22,999 --> 00:00:25,271 But that sounds really hard. 11 00:00:25,271 --> 00:00:28,979 I mean, we all know how to make and break electrical connections with a switch - 12 00:00:28,979 --> 00:00:32,605 you just gotta touch the metal together and then pull it apart real fast! 13 00:00:32,605 --> 00:00:38,565 And we also have these clock things that have an hour hand that slowly turns in a circle twice a day. 14 00:00:38,565 --> 00:00:39,844 But y’know… 15 00:00:39,844 --> 00:00:45,300 some of ‘em only rotate once a day for those that prefer their time served that way. 16 00:00:45,300 --> 00:00:50,688 I wonder if we could connect the technology of clocks with switches. 17 00:00:51,460 --> 00:00:53,431 Oh look, it’s a that! 18 00:00:54,140 --> 00:00:56,652 OK, like a door that’s left its frame, 19 00:00:56,652 --> 00:00:58,781 that intro was unhinged. 20 00:00:58,781 --> 00:01:02,757 I’m sure you’ve seen these things before, they’ve been around for a long time. 21 00:01:02,757 --> 00:01:06,099 In fact, I’m not even sure how long they’ve been around. 22 00:01:06,099 --> 00:01:09,081 Thanks to that Nintendo thing all the youngin’s are playing with 23 00:01:09,081 --> 00:01:13,122 internet searches involving the word “switch” are ruined. 24 00:01:13,122 --> 00:01:19,217 Now, I found a time switch from 1921 which automatically turns stairway lights off after three minutes, 25 00:01:19,217 --> 00:01:22,019 but that’s not what I want to talk about here. 26 00:01:22,019 --> 00:01:24,533 I want to talk about ordinary timer switches: 27 00:01:24,533 --> 00:01:29,128 the kind where you tell it an on and off time and it repeats that daily. 28 00:01:29,128 --> 00:01:34,430 I suppose this is a sufficiently obvious idea that it got implemented in one way or another 29 00:01:34,430 --> 00:01:37,146 just as soon as we figured out the light bulb. 30 00:01:37,146 --> 00:01:41,274 All we really need is a clock that can actuate a switch. 31 00:01:41,274 --> 00:01:47,579 In theory this could be as simple as a rotary switch which gets hit by the hand of an ordinary wind-up clock. 32 00:01:47,579 --> 00:01:52,090 When it collides with the switch, it would turn it from off to on and back. 33 00:01:52,090 --> 00:01:55,567 To make this a little more flexible, instead of giving that clock hands 34 00:01:55,567 --> 00:01:59,178 we can use a wheel that rotates once per day. 35 00:01:59,178 --> 00:02:04,875 Then we could attach little actuators to that wheel that will hit the switch, and there you go - 36 00:02:04,875 --> 00:02:07,042 you’ve just made a timer switch! 37 00:02:07,042 --> 00:02:10,367 Let’s take a look at this consumer-grade timer switch. 38 00:02:10,367 --> 00:02:15,649 This Intermatic Time-All was a staple of American life - or at least some American lives - 39 00:02:15,649 --> 00:02:20,090 in the nineteen seventiesss? Probably? 40 00:02:20,090 --> 00:02:24,720 I’m having a heckuva time tracking down specific dates for this model’s introduction 41 00:02:24,720 --> 00:02:31,724 but it’s old enough that it doesn’t have a polarized plug - which makes it borderline useless today. 42 00:02:31,724 --> 00:02:38,140 But, sure enough, it’s basically a weird-looking 24 hour clock that has a wheel instead of hands, 43 00:02:38,140 --> 00:02:43,700 and hanging around the edges of that wheel are these little movable tabs marked “ON” and “OFF.” 44 00:02:43,700 --> 00:02:48,801 You can move them by pushing them down, and then they’ll slide around the edge of the wheel. 45 00:02:48,801 --> 00:02:53,450 Simply put the ON time where you want it, then the OFF time where you want it. 46 00:02:53,450 --> 00:02:56,930 Of course, you also need the clock to be set to the right time. 47 00:02:56,930 --> 00:03:03,569 You set the time by turning the wheel so that the current time lands where the “Time of Day” pointer is pointing. 48 00:03:03,569 --> 00:03:09,802 Sticking out the side of the device near that spot is a little black knob that’s also marked “ON” and “OFF.” 49 00:03:09,802 --> 00:03:13,941 That is the actual switch mechanism that the clock activates. 50 00:03:13,941 --> 00:03:20,452 And when I turn the dial by hand, I encounter resistance once the tabs get near that knob. 51 00:03:20,452 --> 00:03:23,799 Keep turning and you’ll see that the knob starts to move. 52 00:03:23,799 --> 00:03:27,016 And right when the tab hits the “Time of Day” indicator 53 00:03:27,016 --> 00:03:27,930 *click* 54 00:03:27,930 --> 00:03:31,298 the knob snaps into the OFF position. 55 00:03:31,298 --> 00:03:36,481 Cleverly, the ON tab can only turn the switch from OFF to ON - 56 00:03:36,481 --> 00:03:42,389 if the switch is already on, well the ON tab doesn't do anything as it passes the switch. 57 00:03:42,868 --> 00:03:44,353 Same goes for the OFF tab. 58 00:03:44,353 --> 00:03:48,213 If the switch is already off, that tab won’t do anything. 59 00:03:48,213 --> 00:03:52,548 This not only prevents the timer from slipping into the inverse of what you want, 60 00:03:52,548 --> 00:03:59,990 but it also means that you can manually flip this to ON or OFF to give a temporary override without screwing up the programming. 61 00:03:59,990 --> 00:04:05,410 The timer will resume normal timed operation when the correct tab hits the switch once more. 62 00:04:05,410 --> 00:04:07,060 I’ll show you how that works in a moment 63 00:04:07,060 --> 00:04:12,916 but I want to point out that since this really is just a clock attached to a switch, 64 00:04:12,916 --> 00:04:15,265 that clock could be powered by anything. 65 00:04:15,265 --> 00:04:17,655 It could be a wind-up mechanical clock, 66 00:04:17,655 --> 00:04:19,499 or a battery-operated clock, 67 00:04:19,499 --> 00:04:25,112 or even gravity driven with chains if you were particularly eccentric. 68 00:04:25,112 --> 00:04:29,651 But as this thing's gonna get plugged into a wall outlet since... 69 00:04:29,651 --> 00:04:34,325 that’s its whole thing, the clock mechanism is driven by a synchronous motor. 70 00:04:34,325 --> 00:04:40,349 That's a special kind of motor that spins in lock-step with the frequency of incoming AC power. 71 00:04:40,349 --> 00:04:45,999 Since grid operators do a fine job of making sure that power runs at exactly the right frequency, 72 00:04:45,999 --> 00:04:50,554 and will even make adjustments day-by-day to account accidental for drift, 73 00:04:50,554 --> 00:04:54,586 it serves as a reliable basis for keeping track of the time. 74 00:04:54,586 --> 00:04:56,597 At least, usually. 75 00:04:56,597 --> 00:05:05,725 Since the AC line voltage here runs at 60 Hz, that means the motor will spin at 3600 RPM (assuming it’s a single pole motor). 76 00:05:05,725 --> 00:05:11,845 That’s, of course, way too fast so a ton of gear reduction is used to slow it down to 77 00:05:11,845 --> 00:05:17,658 .00069 (nice) RPM or 1 RPD - 78 00:05:18,409 --> 00:05:20,602 revolutions per day. 79 00:05:20,602 --> 00:05:25,308 Anyway, here’s where the actual switching and the timing of that comes into play. 80 00:05:25,308 --> 00:05:29,389 First let’s talk about the electrical switch that makes this thing useful. 81 00:05:29,389 --> 00:05:32,954 In this timer it’s almost hilariously crude. 82 00:05:32,954 --> 00:05:38,297 Incoming power from the blades runs right to the terminals of the outgoing receptacle, and - 83 00:05:38,297 --> 00:05:39,046 woah. 84 00:05:39,546 --> 00:05:42,638 Hang on, those terminals? 85 00:05:42,638 --> 00:05:48,086 They’ve got bumps on them which actually engage with the holes in a plug! 86 00:05:48,086 --> 00:05:50,323 Finally we found something! 87 00:05:50,323 --> 00:05:52,655 No surprise it’s old. 88 00:05:52,655 --> 00:05:57,885 Anyway, one blade has a simple wire link attaching it directly to the incoming power, 89 00:05:57,885 --> 00:06:04,107 and the other runs through two formed pieces of brass that touch through a contact right here. 90 00:06:04,107 --> 00:06:09,839 The pokey-outey knob of the power switch attaches to a shaft running through the timer body, 91 00:06:09,839 --> 00:06:17,320 on the other end of which is a simple rectangular bit of plastic which either pushes the contacts apart or lets them the touch. 92 00:06:17,320 --> 00:06:23,354 A simple 90-degree turn of that shaft is all that’s needed to change switch states. 93 00:06:23,354 --> 00:06:25,669 As discussed previously on this channel, 94 00:06:25,669 --> 00:06:31,321 electrical switches should have a snap-action to prevent arcing from damaging the contacts. 95 00:06:31,321 --> 00:06:37,340 Here that’s accomplished with a simple arrangement of two pieces of metal which act like leaf springs. 96 00:06:37,340 --> 00:06:40,293 They surround a square cross-section of the switch shaft, 97 00:06:40,293 --> 00:06:44,520 keeping a slight amount of pressure on it and holding it in-place. 98 00:06:44,520 --> 00:06:50,919 As the shaft is turned, the corners of the square start to distend the leaf springs by an increasing amount - 99 00:06:50,919 --> 00:06:54,416 thus increasing the force required to turn the switch. 100 00:06:54,416 --> 00:07:01,547 But once the square is just past the 45 degree mark into a turn, the springs will now help turn the switch 101 00:07:01,547 --> 00:07:04,895 and it quickly snaps into the next position. 102 00:07:04,895 --> 00:07:10,203 This design relies on the timer’s plastic shell to hold the top half of the spring in-place, 103 00:07:10,203 --> 00:07:17,675 as well as to put pressure right on this spot of the brass link to make the contacts actually touch. 104 00:07:17,675 --> 00:07:21,053 So then, here’s how the automatic switching happens. 105 00:07:21,053 --> 00:07:25,580 There’s more going on with those sliding tabs than you can see from above. 106 00:07:25,580 --> 00:07:27,941 As the dial turns with the passage of time, 107 00:07:27,941 --> 00:07:31,610 the ON and OFF tabs slowly approach the switch knob. 108 00:07:31,610 --> 00:07:36,886 The OFF tab has a protrusion that will collide with this wing on the switch shaft - 109 00:07:36,886 --> 00:07:41,601 time marches on, though, so the tab will slowly rotate the switch. 110 00:07:41,601 --> 00:07:48,280 And once it’s pushed it far enough, the switch snaps into the next position, opening the switch contact. 111 00:07:48,280 --> 00:07:53,900 Notice that there are only two wings on the shaft - now that it’s in the OFF position, 112 00:07:53,900 --> 00:07:59,330 the OFF tab on the timer’s wheel can no longer change the timer’s state. 113 00:07:59,330 --> 00:08:04,630 The wings are parallel to the wheel and at this point are useless. 114 00:08:04,630 --> 00:08:09,576 Further into the timer, though, we find another pair of wings on the switch shaft - 115 00:08:09,576 --> 00:08:13,210 a pair in the opposite orientation as the first. 116 00:08:13,210 --> 00:08:17,392 The timer’s ON tab has a protrusion just like the OFF tab, 117 00:08:17,392 --> 00:08:22,967 but it’s positioned inward so it can only collide with this second wing. 118 00:08:22,967 --> 00:08:26,126 Once it does, of course, it pushes the wing forward, 119 00:08:26,126 --> 00:08:30,953 turning the shaft, and eventually it clicks over into the ON state. 120 00:08:30,953 --> 00:08:36,908 This staggered arrangement is how the manual override can work without screwing up the timer settings - 121 00:08:36,908 --> 00:08:43,120 the ON tab can only ever turn the timer on, and the OFF tab can only ever turn the timer off. 122 00:08:43,120 --> 00:08:46,897 If it’s already in the same state as the tab would turn it to, 123 00:08:46,897 --> 00:08:49,372 the tab has nothing to grab hold of. 124 00:08:49,372 --> 00:08:53,329 This design also allows you to pull the switch knob out slightly, 125 00:08:53,329 --> 00:08:57,153 which takes those tabs entirely out of alignment with the switch, 126 00:08:57,153 --> 00:09:02,329 thus turning this into a manually-operated switch until you push the knob back in. 127 00:09:02,329 --> 00:09:04,370 A nice feature, I suppose. 128 00:09:04,370 --> 00:09:06,735 While this design works and works well, 129 00:09:06,735 --> 00:09:08,432 it’s also somewhat limited. 130 00:09:08,432 --> 00:09:16,240 You can only pick a single on and off time, and the shortest duration you can have between them is two and half hours. 131 00:09:16,240 --> 00:09:24,830 To alleviate these limitations, eventually Intermatic would change this design from sliding tabs to removable tabs. 132 00:09:24,830 --> 00:09:27,710 This timer here is one such example. 133 00:09:27,710 --> 00:09:31,970 The overall method of operation is remarkably similar to the first timer. 134 00:09:31,970 --> 00:09:35,025 We have a rotary switch, though now it’s up here, 135 00:09:35,025 --> 00:09:40,970 and the on and off tabs simply push that switch into the next position when they collide with it. 136 00:09:40,970 --> 00:09:45,030 The green tab turns it on, and the red tab turns it off. 137 00:09:45,030 --> 00:09:50,339 The two tabs have their switch actuator pokey bits at different depths so, just as before, 138 00:09:50,339 --> 00:09:54,180 the on tab can only turn it on and vice versa. 139 00:09:54,180 --> 00:09:56,413 The similarities don’t stop there, though. 140 00:09:56,413 --> 00:10:01,222 Internally we have a remarkably similar motor and gear reduction drive, 141 00:10:01,222 --> 00:10:04,804 and the switch itself is still quite crude. 142 00:10:04,804 --> 00:10:06,795 It’s also damaged on this one because 143 00:10:06,795 --> 00:10:10,886 SOMEBODY decided they should hide a screw underneath the clock dial 144 00:10:10,886 --> 00:10:15,490 and I didn’t figure that out until AFTER I went ham with a screwdriver and pliers. 145 00:10:15,490 --> 00:10:18,748 Anyway, this time they’ve refined the switch 146 00:10:18,748 --> 00:10:24,399 by making the switch blades double as the springs which provide that nice snap-action. 147 00:10:24,399 --> 00:10:27,130 But otherwise it’s still just as crude - 148 00:10:27,130 --> 00:10:30,681 are these wires even soldered to the motor leads? 149 00:10:30,681 --> 00:10:35,048 Oh but this time they did at least take care to switch the hot leg. 150 00:10:35,048 --> 00:10:41,545 In the old timer, if you installed it upright on the most-common outlet orientation you’ll find here, 151 00:10:41,545 --> 00:10:43,403 the switch broke the neutral. 152 00:10:43,403 --> 00:10:45,179 Very good. 153 00:10:45,179 --> 00:10:47,702 I mean it wasn’t polarized anyway but still. 154 00:10:48,000 --> 00:10:55,030 Anyway, since you actually remove and replace these tabs on this design to set the on and off times, 155 00:10:55,030 --> 00:10:58,740 you can add more if you want a more complex program. 156 00:10:58,740 --> 00:11:03,273 When new these timers came with two or maybe three pairs of tabs, 157 00:11:03,273 --> 00:11:12,990 but tabs are very easy to lose and unfortunately Intermatic didn’t think of designing some sort of tab-holder into this to store them. 158 00:11:12,990 --> 00:11:17,682 You’d think this might be for that purpose but nope, they don’t fit there, 159 00:11:17,682 --> 00:11:21,980 so those extra tabs tended to disappear. 160 00:11:21,980 --> 00:11:24,692 Don’t worry, they sell replacements! 161 00:11:24,692 --> 00:11:27,764 Actually as a matter of fact you can still buy this timer new, 162 00:11:27,764 --> 00:11:30,286 though stock appears to be dwindling. 163 00:11:30,286 --> 00:11:35,404 Also, you can indeed put the tabs right next to each other and the timer will work - 164 00:11:35,404 --> 00:11:40,896 so if you want something to be on for just a half-hour, well now you can do just that! 165 00:11:40,896 --> 00:11:43,637 Luckily, at some point somebody asked 166 00:11:43,637 --> 00:11:48,243 “why are we faffing with those tabs?” and designed a timer like this one. 167 00:11:48,243 --> 00:11:55,538 Now, the face of the timer has 48 individuals tabs along its perimeter which can be up or down. 168 00:11:55,538 --> 00:12:03,726 Annoyingly these things almost never bother with printing “up is off, down is on” so it’s always a game of trial and error setting one up, 169 00:12:03,726 --> 00:12:08,764 but once you figure it out you’ve got all the flexibility this design could ever offer, 170 00:12:08,764 --> 00:12:14,520 and without the risk of losing the tabs since they’re now permanently attached to the timer. 171 00:12:14,520 --> 00:12:22,253 Internally, we still have a synchronous motor and gear reduction making the dial rotate once per day by way of this drive gear, 172 00:12:22,253 --> 00:12:27,959 but now we have an off-the-shelf microswitch doing the switching with micro flair. 173 00:12:27,959 --> 00:12:32,412 A simple lever connects the switch’s actuator to the perimeter of the dial. 174 00:12:32,412 --> 00:12:39,430 In this design, the dial acts as a very slowly turning cam which that lever rides against. 175 00:12:39,430 --> 00:12:41,309 When the tabs are in the down position, 176 00:12:41,309 --> 00:12:46,430 they push on that lever which depresses the switch actuator allowing power to flow. 177 00:12:46,430 --> 00:12:52,079 However, when they’re in the up position they leave space for the lever to fall into, 178 00:12:52,079 --> 00:12:55,501 and that releases the switch, opening the contact. 179 00:12:55,501 --> 00:13:00,798 Microswitches have their own internal spring mechanism to make the switch action happen quickly; 180 00:13:00,798 --> 00:13:03,458 you can hear it clicking when I depress it manually. 181 00:13:03,458 --> 00:13:05,209 *clicky clicky clicky click* 182 00:13:05,209 --> 00:13:08,273 And since it always wants to push that actuator out, 183 00:13:08,273 --> 00:13:15,239 the switch will in effect turn itself off as soon as the lever falls into the cam thanks to a pulled-up tab. 184 00:13:15,239 --> 00:13:20,352 This design also allows for a simple slider to provide a program override - 185 00:13:20,352 --> 00:13:25,698 slide this over and now the switch is pressed in regardless of the tab situation. 186 00:13:25,698 --> 00:13:30,137 However, it won’t automatically resume the program like the Intermatic timers will. 187 00:13:30,137 --> 00:13:34,848 It will only return to the program when you switch it back to timed operation. 188 00:13:34,848 --> 00:13:38,371 Now, in case you haven't realized, it's 2023. 189 00:13:38,371 --> 00:13:43,746 These days we have more phosticated ways of timing when things can and cannot get power. 190 00:13:43,746 --> 00:13:47,966 But mechanical timers like these still have their applications. 191 00:13:47,966 --> 00:13:52,068 I whip out a few during Christmas time for some indoor lighting displays. 192 00:13:52,068 --> 00:13:59,780 And it can be nice to set up, say, a floor lamp on a timer like this to give you some light when you get back from a day out and about. 193 00:13:59,780 --> 00:14:02,866 It may be basic, but it’s still automation. 194 00:14:02,866 --> 00:14:09,693 And in the commercial realm, you still see similar timers used for things like defrost cycles in refrigeration equipment, 195 00:14:09,693 --> 00:14:13,050 lighting signage so it goes out after closing time, 196 00:14:13,050 --> 00:14:16,220 or even just exterior lighting in general. 197 00:14:16,220 --> 00:14:21,691 Though photocells are usually a better option since the sun does that thing where the days get longer and shorter. 198 00:14:21,691 --> 00:14:24,420 But as electronicals get cheaper and cheaper, 199 00:14:24,420 --> 00:14:30,930 well now it’s just as likely that when you need a basic timer you’ll be getting something like this. 200 00:14:30,930 --> 00:14:34,947 A microcontroller hooked up to a display, some buttons, and a relay 201 00:14:34,947 --> 00:14:37,503 makes for a very flexible timer. 202 00:14:37,503 --> 00:14:40,440 Want different programs for weekdays and weekends? 203 00:14:40,440 --> 00:14:42,019 Knock yourself out. 204 00:14:42,019 --> 00:14:44,410 Concerned about the time drifting with a power outage? 205 00:14:44,410 --> 00:14:50,040 Well, just stick a little rechargeable cell on the board and use a clock crystal as your time base. 206 00:14:50,040 --> 00:14:55,144 You can even get inexpensive timers which, after telling them where you are on the planet and the date, 207 00:14:55,144 --> 00:14:58,793 will automatically adjust sunrise and sunset times throughout the year 208 00:14:58,793 --> 00:15:02,135 all without needing WiFi or an app. 209 00:15:02,135 --> 00:15:03,762 And that’s pretty neat. 210 00:15:03,762 --> 00:15:09,864 Still though, I can’t help but admire the charm that is a clock which turns a switch. 211 00:15:09,864 --> 00:15:12,878 Or, I guess, presses a button in some cases. 212 00:15:12,878 --> 00:15:15,926 Take two basic things, smoosh them together, 213 00:15:15,926 --> 00:15:19,004 and you can make a pretty handy new third thing! 214 00:15:19,004 --> 00:15:23,020 Do it well enough, and you can even change the world. 215 00:15:23,020 --> 00:15:26,843 Thanks to Mike for sending these timers my way way back when when, 216 00:15:26,843 --> 00:15:29,656 and of course thanks for watching. 217 00:15:30,573 --> 00:15:33,129 ♫ regularly-scheduled smooth jazz ♫ 218 00:15:33,504 --> 00:15:36,772 I’ve been working on a pretty complex tompic…. Tompic? 219 00:15:36,772 --> 00:15:38,050 Awwwghh 220 00:15:38,488 --> 00:15:39,486 That’s it! 221 00:15:39,486 --> 00:15:41,906 How ‘bout a taste of little November [laughs] 222 00:15:41,906 --> 00:15:45,126 I mean, we all know how to make and break electrictcalkiconnec 223 00:15:46,210 --> 00:15:49,805 I suppose this is a sufficiently obvious idea that it got incorp -- 224 00:15:51,911 --> 00:15:53,329 Dahh, I could’ve made that work. 225 00:15:53,329 --> 00:15:56,569 I suppose this is a sufficiently obvious idea that… 226 00:15:56,569 --> 00:15:58,829 it got implemented in one way or another… 227 00:15:58,829 --> 00:16:00,564 just as soon as we figured out the light bulb. 228 00:16:00,564 --> 00:16:02,699 Why is the pacing so wrong? 229 00:16:02,699 --> 00:16:03,668 *click* 230 00:16:03,668 --> 00:16:06,160 the knob snaps into the off position. 231 00:16:07,411 --> 00:16:09,039 Except I just turned it on. 232 00:16:09,039 --> 00:16:14,640 One blade has a simple wire link attaching it from the from the from the from thing. 233 00:16:14,640 --> 00:16:16,238 Internally we… 234 00:16:17,114 --> 00:16:18,585 good god! 235 00:16:19,919 --> 00:16:22,926 So, it was just about time for this video, eh? 236 00:16:22,926 --> 00:16:26,766 Do you think when doing inventory, after discovering a lack of certain herbs, a chef will yell 237 00:16:26,766 --> 00:16:28,972 "we're running out of thyme!"? 238 00:16:28,972 --> 00:16:34,194 I mean, if I worked as a chef, you can bet your bottom dollar that I would. 239 00:16:34,965 --> 00:16:36,215 Every thyme.