Hacked Gadgets Forum

February 27, 2014

iPhone Unlocks Door with the help of a Raspberry Pi a Wood Spoon and a Tea Cup

at 11:50 pm. Filed under DIY Hacks, Funny Hacks


Fabrizio Giordano used some items in his kitchen to allow him to remotely unlock his apartment door. When you are in an apartment you will quickly eat up your damage deposit if you start drilling holes for wires and screw things to the walls and doors. With a bit of tape and some wires hanging in some creative ways Fabrizio was able to mount his unlocking mechanism so that he can now use his phone to do some fancy remote unlocking. The taped on wooden spoon might look a bit unsightly but when you compare it to the professional method which usually involves cutting in a door strike into the frame of the door I think he selected the best method.

February 26, 2014

DIY Four-Terminal Kelvin Sensing Connection

at 11:41 pm. Filed under Insane Equipment


If you are taking very low resistance measurements you have a few options. Many meters have a low ohms mode where you are able to zero out the meter resistance but the best method is using a Four-Terminal ohm meter and appropriate connection. In the video above ROBRENZ shows us some typical issue with the clips that are currently available and as a machinist he also demonstrates with some very intricate work that it is possible to improve on what is being used in industry. If that isn’t enough he also demonstrates how the current design of kelvin probes is flawed, the second video demonstrates his solution to the issue. Of course if he was selling one of these solutions it would probably cost more than the meter it is to be used on and unless you are measuring something of extremely low resistance the benefits would not warrant the insane build effort.


February 25, 2014

Remote Flower Watering Project

at 12:55 pm. Filed under DIY Hacks, Electronic Hacks

Remote Flower Watering Project_2


Lucy Matchett, Nicole Yi Messier, and Joselyn McDonald used Spacebrew to make this Remote Flower Watering Project. This fun little project uses a photoresistor to detect when a watering cup has been lifted off the base and sends this information to the remote unit, the remote unit then pours the water that has been prepared onto the plant using a small servo motor.The only issue is that someone on the remote side needs to full up the little cup so that it can be poured at some point, of course they could just pour it themselves at this point. I think a large vessel of water (something like a 2 liter pop bottle) that is connected with a solenoid valve would be an ideal upgrade, instead of pouring a small cup of water allow a metered dose of water to flow when activated. Of course the actual specific project is not the point, it is the building blocks that are learned by seeing the project are the useful part here!


Forget Me Not Remote Flower Watering from Joselyn Neon McDonald on Vimeo.


Remote Flower Watering Project

February 23, 2014

Dummy Load Water Bucket

at 8:36 am. Filed under What Were They Thinking


When you need to ensure your power supply is up to snuff a dummy load is often used when it isn’t feasible to test with the real load. You will often see this on a big scale when load testing emergency generators. Normally you would use a large resistive load that is air cooled by fans.  Mikeselectricstuff demonstrates his array of resistive loads but for a new project he didn’t want to build another one for his new project so he did some out of the box thinking. He shorted the output of the power supply with the right length of light gauge wire to draw the load needed. Normally this type of wire would heat up and melt with any significant load so he put it into a large tub of water to allow for direct cooling. The wire he selected is enameled so that it doesn’t short out to adjacent wires in the tub but provides for virtually no thermal resistance so the water can draw away the heat. 

Name the Thing Contest – 249

at 1:41 am. Filed under Contests



The prize this week is an Arduino Pro Mini. This contest will run for one week (February 23 – 28, 2014). Ending time is based on central standard time. To enter, identify the item above and what it can be used for. Please note the image above is a side view of the thing.

Please do not give the answer in the comments.

Send an email to contest @ hackedgadgets.com with “Name the Thing Contest” as the subject, and the message body consisting of:

  • The name of the item in the above picture
  • An example of what the item pictured above can be used for

The winner will be chosen at random from all of the correct entries.


Added April 13, 2014

The item to guess was a trumpet speaker.

The winner is John C. (there were 319 entries)


Below is a picture of the prize.


February 22, 2014

DIY Solder Fume Extractor Built Into Electronic Workbench

at 8:05 am. Filed under DIY Hacks

DIY Solder Fume Extractor


When working on your latest project you will eventually need to take it from breadboard to perf board. This is a fun step but unfortunately involves lots of smoke from the solder flux. There are lots of techniques to combat the smoke cloud, slowly blowing as you solder, holding your breath and turning away to breath, using a small fan to blow across your work and  fume extractors (sucking fan with a filter) just to name a few. Corgi-Tronics provides an example of a great DIY Solder Fume Extractor that he built into his latest bench design.  He used a bathroom exhaust fan to suck air through a 2.5 inch pipe which has a removable articulating end on it for accurate positioning. He is dumping the air at floor level 6 feet away but having a gate valve to allow direct outdoor venting would be a great update.

February 21, 2014

Inductive Loop Vehicle Present Sensor

at 11:48 pm. Filed under DIY Hacks, Electronic Hacks

Inductive Loop Vehicle Present Sensor


When leaving a parking garage have you ever wondered how the gate knows how to close only after you have pulled out? The magic lies below the concrete, there is an inductive loop in the ground under the gate arm. It sensed the presence of your car and lets the gate close only once your car can no longer be detected. You can also see these loops used in modern intersections to control the traffic lights as efficiently as possible, for example when there are no cars in the turn lane there is no need to waste 30 seconds flashing the turn arrow while holding back the through traffic.  

Thanks to our friend Muris for creating a DIY Inductive Loop Vehicle Present Sensor and providing all the details so you can build your own or modify the design for your own needs. It has a PIC16F877A to control the show and has a ton of adjustability so it can be used for almost any situation.


  • Tuning: Automatic
  • Detection type: Presence/Pulse
  • Presence time: Adjustable in 4 steps (default: 11 min, 33 min, 55 min, infinity)
  • Pulse duration: 100 ms / 500 ms
  • Signal filtering: Adjustable in 4 steps (LOW, MED-LOW, MED-HI, HI)
  • Coil/loop inductance: 20 uH – 1000 uH
  • Frequency range: 40 kHz – 140 kHz
  • Frequency adjustment: 4 steps (LOW, MED-LOW, MED-HI, HI)
  • Sensitivity: 0.001\% – 0.5\% digital in 8 configurable steps
  • Detection speed: <10 ms (with LOW filtering stage and loop frequency of 40 kHz)
  • Startup time: ~8 sec
  • Power supply: 7-40 V DC / 5-28 V AC
  • Current consumption: ~0.035 A
  • Protection: Galvanic isolation + gas discharge tube for lightning protection”



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