Tag: hardware

Here’s another office cleaning find. Last fall I came across some interesting batteries on the internet and I purchased a few to try them out. They are rechargeable AA batteries that have a built in USB plug so they can charge directly from a computer. It’s a neat idea. There are times when I’ve wanted to charge batteries but I didn’t want to bring an extra charger along with me. They were surprisingly cheap (around $3 per battery, rather than $10 per battery for competing products).

They came from Deal Extreme, a Chinese gadget seller with surprisingly cheap/free shipping to the U.S. The catch is that it’s postal service and it takes a couple weeks to arrive. It doesn’t appear that Deal Extreme has any of these left, but their are similar (and more expensive) units available elsewhere on the web.

Somewhat to my surprise, the batteries actually work as advertised. They are not the longest lasting rechargeables around (I think they have a 1350 mAh capacity rather than the larger 2200 mAh). I used them in my bike headlight all winter and now Melissa uses them in her bike headlight. I could easily charge them while at work without the need to bring a separate charger.

The batteries bear the brand name “Exceed King”

Each battery has a cap on the bottom that, when removed, reveals a built in USB plug.

The translated directions on the back of the package are fairly hilarious. In case you can’t read it in the picture, it says:

When battery capacity insufficiency, takes down the the battery the nearcathode black to be partial, reveals the battery the USB connection, inserts the computer the USB place already to be possible to charge, duration of charging 4 hours.

Note:

Befre the use please confirmed the battery cathode. Please hastilyopens the solution battery, the electric appliance does not need to besupposed for a long time to take out the battery, the battery hastilyinvests in the fire.

There you have it. Just try not to hastilyinvest in the fire.

Our new Mac Pro came with 2 GB of memory, which I promptly upgraded to 6 GB. I was shocked that:

• The FBDIMMs have heat sinks
• The heatsinks are enormous

Canon makes a SLR camera remote timer that sells for a couple hundred dollars. Using inspiration from various web sites I built one for myself using about $15 worth of parts from RadioShack.

First, it is a simple wired camera remote control. Just plug the cable into the remote jack on the Canon SLR camera and the black button on top will trigger the camera auto focus, while the red button will focus then take a picture.

Second, it is a timer than can be used for time lapse photography. A 9-volt source (battery or DC adapter) powers a circuit I built using a 555 timer and a 6-way rotary switch where each way is hooked up to different resistors. Switching between these different resistors varies the timer interval. The timer triggers a relay switch at specified intervals which causes the camera to take pictures. It is based on the astable 555 timer circuit described here. I used the following capacitor and resistors:

• C = 3300 µF
• R1 = 1000 Ω
• R2 = 620 Ω (~5 second delay)
• R2 = 2670 Ω (~15 second delay)
• R2 = 10000 Ω (~48 second delay, I just realized I calculated this one incorrectly, as I intended for it to be 30 seconds)
• R2 = 15000 Ω (~1 minute delay)
• R2 = 65000 Ω (~5 minute delay)
• R2 = 200000 Ω (~10 minute delay)

Here are some photos of the actual device:

Okay, so the innards are a little sloppy. This was my first real electronics project. The soldering took some practice, and I actually hosed my first circuit board and had to start it over.

Here is a simple example of the sort of thing this timer allows me to do. I set it up to take a picture of a glass of ice cubes every minute for a couple of hours (i.e. until the battery in my camera ran out).

Ah, stupid YouTube! The aspect ratio is wrong, but you get the idea.