$1 Lithium Coin Cell Charger

Got a buck? Make a charger for LiR2032 coin cells. It could hardly be cheaper or easier.

Bike Rack From Scrap Fence

Something had to be done with the heap of bikes in the garage. Fence panels welded along the edges made for a quick and cheap solution.

I2C LED Display From Hacked Voltmeter

LED voltmeters are a cheap source of 7 segment displays and can easily be repurposed. Using the I2C protocol, a master microcontroller such as an Arduino Uno can govern multiple displays with just 2 I/O pins.

Free Shower

A street scene in Philadelphia: the first city in the USA to have fire hydrants.

Bike Trailer Welded From Trash

A cargo trailer is a great bike accessory, especially if you can weld one together for next to nothing. This artifact bears a slight resemblance to a bed frame on wheels. There's maybe a reason for that.

£1 Lithium Ion Battery Charger

One cheap PCB from an auction site. 1 scrap bit of copper pipe. 2 bronze pennies. Put them together and charge up a 18650 Li ion cell.

3x Battery Teardown

So if you open up a 9 V battery, you find 6 thin 1.5 V cells inside. But what was inside that lantern battery, the rechargeable PP3, or the funny shaped lump on the back of my laptop? Confronted with dead metal in the recycling drawer, I tried to find uses for the contents.

?

?

?

Home Made Arduinos

Making Arduinos was pretty laborious. The toner transfer went well, but drilling was a dental experience.

DIY PCBs By Stovetop Toner Transfer

If the clothes iron method fails for you, try this new twist on the toner transfer process. Put a heavy hotplate on the stove and dial in a temperature of 175 °C using a thermocouple. Bond the toner image to the copper clad board by placing them print side down onto the hotplate between two sheets of paper and applying pressure with a rolling pin for 2-5 minutes. For double sided boards, flip every 30 seconds or so.

Bike Basket Hack

The affordable panier, seen wherever there are students in Philadelphia.

DIY Solder Flux From Pine Resin

My flux pen recently bit the dust. Fortunately the raw material was close at hand. Making solder flux from rosin is a snap — and a pine tree near my house was oozing big dollops of gum.