Hacked Gadgets Forum

September 8, 2014

How Ferrite Beads Work – EMI Suppression

at 8:40 pm. Filed under Educational

How Ferrite Beads Work - EMI Suppression_4

 

If you are working on a project where you want to get rid of EMI from entering an input you might want to look into using some ferrite beads, they can help you out in removing high frequency noise from your circuit. The ferrite looks like a variable resistor that has no impact on your circuit at low infrequence and starts to conduct to short out higher frequencies. It does this by converting the energy that is suppressed into heat.

“Ferrite beads prevent interference in two directions: from a device or to a device. A conductive cable acts as an antenna if the device produces radio frequency energy, this can be transmitted through the cable, which acts as an unintentional radiator. In this case the bead is required for regulatory compliance, to reduce EMI. Conversely, if there are other sources of EMI, such as household appliances, the bead prevents the cable from acting as an antenna and receiving interference from these other devices. This is particularly common on data cables and on medical equipment.”

 

 

 


Raspberry Pi Model Train Controller

at 5:35 am. Filed under Cool Gadgets

 

The Raspberry Pi is a very powerful heart of many cool projects including this Raspberry Pi Model Train Controller by MrNotbuyinit. The description of the electronics starts at around 2:35. The prototype interface from the Pi is a simple breadboard which looks to be ideal for quick and easy additions and modifications. The Pi is interfacing with a port expander to get more digital outputs out of the Pi. A keyfob is connected to a receiver board that is great to control the system remotely. IR sensors are used to detect where the trains are on the track.


September 7, 2014

Arthur Benjamin – Mathemagician

at 10:23 pm. Filed under What Were They Thinking

 

Are you good at math? Not sure you will think that after you watch the TED Talk featuring Arthur Benjamin, the Mathemagician.

“Dr. Arthur Benjamin is both a professor of mathematics and a magician. He has combined his two loves to create a dynamic presentation called “Mathemagics,” suitable for all audiences, where he demonstrates and explains his secrets for performing rapid mental calculations faster than a calculator.”

 

 


September 4, 2014

HLK-RM04 Serial to WiFi Module

at 10:45 pm. Filed under Educational, Electronic Hacks

HLK-RM04 Serial to WiFi Module

 

If you are looking to add some WiFi connectivity to your next project the HLK-RM04 Serial to WiFi Module might be just the thing if you want to go wireless. The $10 HLK-RM04  module handles all of the WiFi overhead so your microcontroller project can simply send serial data to it using the TX and RX pins. RAYSHOBBY.NET has a great tutorial including code to get you started with this module.

Via: Dangerous Prototypes

“The chip (RT5350F) is a 360MHz MIPS core with built-in WiFi support. The module is quite powerful — at factory default settings it functions as a normal WiFi router. Now, in order to get it to talk to a microcontroller like Arduino, I need to use its Serial-to-WiFi capability. What is that? Well it means using the serial (TX/RX) interface to send and receive Ethernet buffers, and similarly using serial to send commands to the module and query or change its current status. This is quite convenient because first, it only takes two wires (TX/RX) of the microcontroller to talk to the module, second, it moves WiFI-related tasks to the module allowing the Arduino code to be very much light-weighted. “


 

September 3, 2014

3D Printed Wall Chain Clock

at 9:24 pm. Filed under Cool Gadgets, DIY Hacks

3D Printed Wall Chain Clock

 

Kaptein QK from the EEVBlog Forum shows off his 3D Printed Wall Chain Clock. The clock uses a Arduino Nano for the brains but he opted to code it in C using the AVR Studio 6, the stepper motor is being driven using an L298N dual H bridge. You can watch the clock in action below. This is a great clock for glancing at to see what the approximate time is quickly.

 

 


September 2, 2014

Black and Decker 2 Slice Toaster T2707SKT Repair and Teardown

at 10:32 pm. Filed under Reviews, Teardown

 Black and Decker 2 Slice Toaster T2707SKT Repair and Teardown_8252

 

This time we will be taking a look at a Black and Decker model T2707SKT Toaster. Not that I was looking for a toaster to teardown but I just happened to stumble across it at my local XS Cargo store. It was a factory reconditioned unit that was then returned. The issue listed on the ticket was that one side didn’t heat properly. The regular price was around $30 or so and it was sitting on the discount shelf for $2. I figured it would make for a good teardown and possibly repair video.

Turns out the design of the toaster is both quite simple and more complex than I would have expected. Let me explain… The actual electrical design of the basic toaster is very simply. There is a large plastic plunger that is connected to the handle that gets pressed down by the user to push the toast down. When pressed there are 2 contacts that are made which transfers the electrical connection from both neutral and hot AC lines to the heating elements. The heating elements consist of one circuit for the outer heating and one for inner heating. Turns out that the inner one was working and the outer one was not.

There is an electromagnet that is used to hold the spring loaded mechanism in the depressed (toasting) position and when de-energized the toast pops up and automatically kills the power to the entire circuit.

There is not much in the way of protection in this device, the chassis is not grounded like many other devices like this. This means that if there is a stray connection from one of the heating lines to an internal metal component the case could be energized. The construction is quite well designed to prevent this though. I would have felt safer if there was a ground connection to the exposed metal housing though. There is also no over temperature sensors that could be seen in this device. Most high wattage devices that generate lots of heat have an internal in line heat sensor that opens at a pre-determined temperature to prevent an over heating issue from becoming dangerous. For example if something accidentally jammed the toaster in the depressed position it would eventually reach a temperature to turn off. I guess with this design the actual heating wires might fail after a short enough time to prevent any dangerous conditions.

The control board is powered in an interesting way. The heating coil for the internal section is tapped at around 12 volts to power the control board, this prevents them needing to design a circuit that first needs to reduce the 110V AC to a usable voltage. The only method of control that the control board has is to energize and de-energize the electromagnet that holds the toast tray down. There is no temperature feedback and the only output that the controller can provide is how long the heat is on. There is a large temperature dial and 4 push buttons but in the end all these do is vary the on time blindly. For some reason I felt that there was going to be some additional smarts in place here. **UPDATE** Alex left a comment about the control chip. I didn’t take a second look at it, I figured it would have been some type of generic timer chip. Was I ever wrong, the chip is a Holtek HT46R005 which is a microcontroller!

Turns out that one of the connections between the heating element and crimp connection was where it failed. This is a failure that can’t be repaired since this connection can’t be soldered due to the natural high temperatures of the connection. It would need to be spot welded or crimped. I don’t have a spot welding machine and there is no room to re-crimp so I simply temporarily twisted a binding wire around the broken connection using some light gauge solid copper wire to allow the system to be tested before it was thrown out.

During the teardown of the unit it was noticed that the AC power cord was squished quite badly in the strain relief clamp. This clamp is a simple piece of plastic that is held in place over a notch in the molded plastic base by 2 screws. I am not sure if this is an isolated incident where the cord is damaged to this extent by being held in place or if this is how most of the cables look after being squished in place. You can see some pictures of this below.

Unfortunately there isn’t much in this unit that can be scavenged. The electromagnet and timer board is the only thing that is of any interest.

Hi resolution pictures can be found here.

 

 

You can see the damaged cord below, this was damaged by the strain relief clamp! See additional pictures of the damage in the picture gallery below.

 Black and Decker 2 Slice Toaster T2707SKT Repair and Teardown_8305  Black and Decker 2 Slice Toaster T2707SKT Repair and Teardown_8302

 

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September 1, 2014

Zetta Z12 Spy Camera Review

at 7:58 pm. Filed under Reviews

Zetta Z12 Spy Camera Review_8254

 

Thanks to Spy Tec for sending the Zetta Z12 Spy Camera in for review. The unit is nice and small, the battery is designed to last long enough to catch the video you need. There are lots of uses for this device, if you have someone that is borrowing your morning paper or leaving your doggy presents on your lawn you can hide this little device to catch the action you need. Unlike a normal security camera you can set it up to just record when there is some activity to be recorded. There is a ton of other activation modes to help you record what you need. To see it in action watch the video below.

Pictures of the device are below, if you would like to see them in full size you can grab those here.

 

 

Specification

Storage temperature 0 to 45degC (32 to 113degF)
Operating temperature 0 to 45degC (32 to 113degF)
Size 7.6 x 4.3 x 1.9 cm
Battery 800mAh 3.7V Li-ion battery
5V Adapter 5V, 600mA DC adapter with mini USB out
Car Adapter 12-24V input, 5V, 750mA car adapter, USB out
Current consumption 80mA
Recording time max 8 hours (with fully charged battery)
Standby time max 90 days (in vibration triggering power saving mode with fully charged battery)
Sensor resolution VGA (640×480)
Sensor sensitivity 6.8V/lux-sec
Sensor viewing angle 62deg
Microphone speech grade
Memory card supported max 64GB microSD card (TF)
Memory usage 45 minute/GB (high frame rate)
3 hour/GB (low frame rate)
Video recording resolution VGA (640×480) or QVGA (320×240)
Video compression JPEG
Voice recording 12kSps, 8bit
Voice compression PCM
File format AVI
USB Mass storage device
OS supported Windows 2000 / XP / Vista / 7 / 8, Mac OS X

 

 

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