Make a cat feeder with Arduino, a servo and two cans

via Arduino Blog

YouTuber “Mom Will Be Proud” and his family have a cat. And like all pets, their feline friend requires fresh food every morning. But rather than disrupt your sleep or daily routine, why not build an automated feeder using some spare parts? This is exactly what the Maker did using an Arduino, a servo, a simple button, a power supply, and two cans–one for housing the electronics, the other for the food.

Mom Will Be Proud cut little openings into each container, and connected them to a servo that rotates one on top of the other without ever getting stuck. A broken IKEA timer and a piece of plastic are used for the button, which when pressed, turn the cans until its holes match up and the food is dispensed into a bowl.

You can see how it works below!

Robot gets peanut butter everywhere but on the bread

via Arduino Blog

What do you do when you’re the Queen of S****y Robots and you’re in the mood for a peanut butter and jelly sandwich? You have a remote-controlled bot make one for you, of course. This is exactly what Simone Giertz set out to do in her latest hilarious project using a pair of robotic arms: one holds a plastic knife for spreading, while the other is puppeteered by her friend, Fiona.

Although this sandwich robot may not be making any PB&Js anytime soon, Giertz’s video will surely have you LOL-ing. Enjoy!

Free PCB Sunday: Pick your PCB

via Dangerous Prototypes

IRToy

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Be sure to use a real e-mail in the address field so we can contact you with the coupon.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.
  • PCBs are scrap and have no value, due to limited supply it is not possible to replace a board lost in the post

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App note: Snubber capacitors for complete insurance of power semiconductors

via Dangerous Prototypes

an_wima_igbt

An application note from WIMA about snubber capacitors, Link here.

The trend of modern semiconductor technology towards increasingly powerful applications results in the fact that switched currents and voltage levels are continuously increased and that simultaneously the switching speed is also increasing markedly.
The developments in the area of power semiconductors include the component group IGBT (Insulated Gate Bipolar Transistor) or IGBT modules.
The switching capacity with shortest switching times which can be realized using IGBTs necessitates an extremely low-inductance circuit design. Even the low self-inductance of the power bus may induce dangerous voltage overshoots between collector and emitter which may result in the destruction of the valuable power semiconductors.
To protect the components, so-called snubber suppressor circuits are used. The most important component in this respect is a low-inductance pulse capacitor in order to attenuate or cut off peak voltages.

App note: Selection of capacitors for pulse applications

via Dangerous Prototypes

an_wima_pulseselection

Guidelines from WIMA about selecting capactiors for pulsed conditions. Link here

The maximum permissible AC voltage that can be applied to capacitors in sinusoidal waveform applications, can be determined from the graphs in the respective capacitor ranges.
However, where pulse conditions exists, the following procedure is to be observed to ensure that the correct capacitor rating is selected for a particular duty:
– Rated voltage
– Maximum current
– Dissipation
– Determining the permissible AC voltage and AC current at given frequencies

Homebrew dummy load

via Dangerous Prototypes

pic-2015-08-12 20.27.22-600

A simple DIY dummy load project from Flathagen:

I have created a simple 50 Ω dummy load to test transmitters. I also added a simple RF diode detector so I can measure the peak voltage, and calculate the power.
The dummy load consists of eight 100 Ω resistors rated at 2 W so the load should handle 16 W, at least for short periods. I constructed the dummy load using a combination of ugly construction and Manhattan style, by gluing pieces of PCB (as isolation pads) on top of a ground plane PCB. Then I soldered the components directly on the copper without drilling holes.

Project info at DIYcrap.