Repaired Microwave Keypad Looks As Good As New

June 23, 2011 by Mike Nathan 15 Comments

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Instructables user [Rohit] had an out-of-warranty microwave with a broken membrane keypad. Much like our friend [Alexandre] from Brazil, he found the cost of replacement parts beyond reasonable, so he had to find a way to repair it instead.

He disassembled the front cover of his microwave to get at the main controller board. Once it was detached, he removed the keypad’s cover to get a closer look at the matrix underneath. While taking notes on how the matrix was wired, he found that some keypad traces connected to other traces rather than buttons. He says that they are likely used by the microwave to detect that the keypad is present, so he made sure to short those traces out on the controller board when he wired everything back together.

He replaced the aging keypad with microswitches, but rather than mount them on the front panel of the microwave, he drilled holes for each switch so that he could mount them inside the face plate. Once everything was wired and glued in place, he re-mounted the keypad’s cover. Now the microwave looks stock but has firm, reliable, user-serviceable buttons that are sure to last quite a while.

Repairing A Broken Microwave Keypad

June 9, 2011 by Mike Nathan 41 Comments

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[Alexandre Souza] needed a microwave pretty badly, but he didn’t have a lot of cash on hand. He located one for a great price, but once he got home he found that things weren’t working quite like they should be (Google translation).

After some investigation, he narrowed the problem down to a bad keypad membrane. Unfortunately for him, this model of microwave was never sold in Brazil (who knows how it got there) and the only membrane he could track down had to be shipped in from the US at a cost of $80.

Rather than pay such a high price for a simple membrane, he opted to fix the microwave himself. He dismantled the control panel and thoroughly traced the keypad matrix to get an understanding of which pins toggled which functions. With a piece of protoboard and almost two dozen push buttons in hand, he built his own keypad and wired it directly into the microwave’s control board.

With labels written in marker it might not be the nicest looking thing you have ever seen, but it works a treat and is a great money-saving hack.

HERF Gun Zaps More Than Your Dinner

March 21, 2011 by Mike Nathan 76 Comments

Instructables user [Jimmy Neutron] had an old microwave sitting around and figured he might as well gut it to build a high-energy radio frequency (HERF) gun.

The concept of a HERF gun is not incredibly complex. Much like your microwave at home functions, a high voltage power source is used to drive a magnetron, which produces micro wave radiation at 2.45GHz. These waves are then guided away from the magnetron using a waveguide, towards whatever the target might be. These waves then energize the target in a similar fashion as the water molecules in your food are energized during cooking.

[Jimmy] has not quite finished his HERF gun as he still needs to build a waveguide for it and then safely mount it for use. In the meantime, check out the pair of HERF guns we found in the videos below.

As a parting note, we must stress that building a similar device is dangerous, very dangerous – especially if you do not know what you are doing. Microwaves contain high voltage components, and exposure to microwave radiation can be deadly under certain circumstances. Stay safe!

Looking for more microwave fun? Check these out!

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Building Linear Amplifier Prototypes

January 28, 2011 by Mike Szczys 15 Comments

We know way too little about this subject but hopefully [Bob4analog] helped us learn a little bit more this time around. He’s building his own linear amplifiers on what looks like sheets of MDF. This is an evolving design and the two videos after the break show two different iterations. He’s salvaged several components, like transformers from microwaves, as well as built his own components like the plate choke to the right of the tubes in the image above. In standby, the amp sits at 2800 volts, warming the filament before the unit is switched on.

So what’s he got planned for this? Good question, but it appears that there’s more than enough power to drive a long-range transmitter.

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Halloween Props: Flying Crank Ghost

October 13, 2009 by Mike Szczys 5 Comments

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[Jake’s] projects have become regular features here on Hack a Day. He keeps the Halloween hack-fest rolling with his Flying Crank Ghost. For the ghost he used a store-bought skull but sculpted some hands himself out of Styrofoam. The body is fashioned from coat hangers with a bit of creepy fabric draped over the hole thing to complete the look.

He added some very convincing motion to the ghoul using a salvaged microwave turntable motor. The motor is mounted in the center of a two crossed boards, and has an armature attached to it. Three strands of monofilament attach to the end of the armature, run through eyelets on the ends of the crossed boards, then attach to the head, and each arm. When the motor is turned on, the armature turns, moving the head and hands up and down at different rates. Take a look at the embedded video after the break to see the final product.

[Jake] does mention that the motor he used is a bit underpowered. We figure this only needs to hold up for one night, so dig through your junk bin and see if you can throw one of these together in a few hours.

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How-to: Build Your Own Spot Welder

June 23, 2009 by Steve Watkins 85 Comments

Spot welders are used in the fabrication of automobiles, PC cases, power supplies, microwave ovens, electrical junction boxes, Faraday cages, and various electronics. A spot welder is used because it produces a highly defined point of contact weld. The materials are welded without excessive heating, so working pieces are handled easily. The weld is also highly controlled and repeatable. In this how-to we cover the basics of a spot welder, and then show you how to build one from a microwave oven transformer.

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Microwave Timer Switch

January 3, 2009 by Caleb Kraft 9 Comments

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[Koil_1] knows he’s forgetful. In order to save himself from any undue harm, or possibly to keep from burning his house down, he felt he needed a timed power switch to run his soldering iron from. He realized he could harvest the relays and timer circuit from a microwave. This allows him to have presets for specific tasks. Considering the fact that you can get a used microwave for free or close to it most of the time, this was a great re use of something that might just go wasted otherwise. Great job [Koil_1].