This workout timer turned out great. We think [Douglas] managed to end up with a professional look and a full range of features even though he was doing a lot of learning along the way.
He wanted a clock that was capable of counting up or down to time different segments of his workout. In order to be really useful it needed to have a remote control and a way to signal when time had run out. He grabbed an Arduino and started prototyping with an LED marquee at first, but after adding a second Arduino to deal with the display scanning issues he finally switched over to these LED segment displays.
The timer includes an IR receiver so that it can be controlled with a handheld remote. The large red bell to the side has a heck of a ding and is used to signal the start and end of timing. Perhaps the driver for that bell could be incorporated into the home automation project from Wednesday. Once the hardware decisions were finalized [Douglas] set out to build an enclosure that he could be proud of (mission accomplished!). Don’t miss the video after the break where he walks through all various aspects of the user interface. Continue reading “Workout timer has its own fight bell”
[Karl] needed a programmable real-time clock for one of his projects. He considered adding an RTC chip, LCD screen, and some buttons for use with a microcontroller. That’s not necessarily hard, but it takes time and can be considered a project in itself. Instead, he headed to the hardware store to look for a cheap solution. He was able to get this AC outlet timer for a song. It’s got everything he needs; twenty programmable on/off events, a calendar to track time and day of week, and a user interface made up of a low-power LCD and four buttons. He cracked open the case and patched into the electronics for use with any project.
You can see the solder-tab battery in the middle of the board (green coin-cell). That actually runs the timer circuitry and display. It’s topped off when the unit is plugged into mains, but [Karl] ended up replacing it with a much higher capacity AA rechargeable battery. The device works just like a thermostat, using very little power and driving a relay at the appropriate time. Batteries in thermostats seem to last forever and we can expect the same performance from this device. [Karl] rerouted the trigger signal from the relay to his own 2N2222 transistor. This way the device can switch loads running at voltages other than its own 1.2V operating level.
Stock timers are great. They’re mass-produced which makes them cheap, and you can do some interesting stuff with them. We really enjoyed see this other mechanical version hacked for hydroponic use.
[Alan] was unimpressed by the cheap ticking egg timers that grace many of our kitchens. He decided this was an execllent opportunity to ply his skills with microcontrollers. He built this kitchen timer complete with an enclosure and audible alarm.
The device is Arduino based, which makes driving the graphic LCD quite easy thanks the libraries associated with that platform. As you can see above, his user interface makes use of virtual buttons – three tactile switches whose function is listed at the top of the display.
But we think the alarm sound really earns this a place in his kitchen. He used the same hardware as that that Super Mario Bros. Toilet project to play classic video game sounds when your soufflé needs come out of the oven. We haven’t come across them ourselves, but apparently there’s a line of key chains for sale in Japan (yes, we need to plan a trip there!) that have the tunes programmed into them. They’re easy to crack open and it beats dealing with a speaker and amp circuit.
When [Todd Harrison’s] Christmas lights stayed on well past the pre-defined shut off time, he knew there was something wrong with the timer. He took the device into his workshop and spent some time diagnosing and repairing the device, a process he recorded for all to see.
After busting the screw-less timer open with a hammer, he inspected the PCB for any apparent signs of damage. After seeing what looked like a damaged transistor, he desoldered it from the board for testing. After the transistor passed his tests with flying colors, [Todd] assumed that the fault had to be in the relay which the transistor was responsible for switching.
Sure enough, the relay had shorted out, and upon cutting it open he found that the contact points were fused together. He separated and sanded the contacts down, enabling him to get the timer working – at least for the time being.
Part of [Todd’s] goal with this video was to show off different methods of desoldering, including a manual solder sucker (my favorite), desoldering braid, and a purpose built desoldering iron. If you’re in the market for some desoldering tools, but don’t know what to buy, [Todd] is more than happy to offer his advice.
Continue reading to see a video of [Todd’s] troubleshooting process.
Continue reading “Troubleshooting household light timers”
Most DSLR cameras have the ability to take pictures at set intervals, but sometimes the menu system can be clunky, and the options are often less than ideal. [Achim] is a big fan of time lapse photography and has been hard at work creating a hardware-based intervalometer to suit his needs. He has just finished the second revision of the controller which is just about small enough to fit inside the housing of a 2.5mm stereo plug. The timer is not 100% universal, but so far he has confirmed it works on Nikon, Canon, and Pentax cameras.
Based on a PIC10F222, the circuit’s operation is quite simple. Once the dongle is connected to your camera, you simply need to take two pictures anywhere from 0.4 seconds to 18 minutes apart. The intervalometer “watches” to see how long you waited between pictures, and proceeds to take shots at that interval until the battery dies or your memory card fills up.
As you can see in the video on his site, the timer works a treat. If you want to make one of your own, swing by his site to grab schematics and code – it’s all available for free.
*Whoops, it looks like we’ve actually covered this before. Our apologies.
After having his mints disappear for quite some time [Quinn Dunki] came up with an idea to get back a the fresh-breath thieves. A bit of circuit design, parts scavenging, and free-form construction led to the creation of his mint-tin burglar system.
Here’s how it works. Flip the on/off switch in the base of the mint tin before you head off for lunch or a coffee break. When the foul-mouthed pilferer hits up your stash they’ll get what they were looking for at first. But by opening the tin they tripped a timer circuit that will send the mints vibrating across the table soon after having been opened.
The breadboard above holds the prototype timer circuit, built around or friend the 555 timer. The vibration motor from a cellphone is a perfect choice for this hack as it’s very small and is just waiting to run from a low-voltage source. We especially liked the use of the cells from inside a 9V battery as a power source and the compact assembly that manages to fit inside the mint container.
When notes stuck to the water heater failed [Ryan] decided to whip up “the world’s most expensive 240V relay” using a servo, a real time clock and of course an Arduino. All in an attempt to save a buck or two thanks to LA’s “Time-of-Use program”.
Using a protoshield Ryan soldered up a RTC module using the DS1307 chip. On board he added some LED’s and switches including a holiday switch keep the heater off, a next cycle button when you need some hot water and to hell with the expense, and a pulsing blue LED.. for no reason at all. The board flips the mechanical switch using a servo and piano wire, simple but effective. We wonder how many days/weeks it will take for it to offset its expense?