Saturday, August 28, 2010

Soldering Sheild Headers


Many Arduino shields are shipped with headers packed loose, leaving it up to you to solder them in place. Sounds easy, right? Actually, it’s more fiddly and annoying than it sounds. Arduino headers consist of four separate headers, and if you get the pins even a little crooked on any of them it can be hard getting the shield to plug neatly into the Arduino. The first few times I soldered headers to shields it took several minutes of cursing, burned fingers, and repeatedly re-flowing the solder on the first joint to get them to sit perfectly straight before soldering the rest of the pins.

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Friday, August 27, 2010

Arduino Robot Goes WiFi


Arduino is very rich in its shields so there is another fast and great project – WiFi controlled Arduino robot. The platform is pretty simple – mainly made of wood. Interesting part is that Arduino is equipped with WiShield from AsyncLab’s that allows controlling bot remotely via TCP.

Thursday, August 26, 2010

WaterValveShield controls your garden spigot

First Ray built a minty water valve controller that gave him control over a garden water supply, then he turned it into a shield.

For the water valve, I picked the Orbit yard watering valve. It's widely available in home improvement stores, and it is cheap. It has two pins: applying +24v opens the valve, and -24v closes the valve. It uses a latch solenoid, drawing power only when you open or close it. This makes it very power efficient.

To use a single li-poly battery to drive the valve, I needed a voltage booster to raise the 3.6v provided by the battery to 24v momentarily before connecting to the valve solenoid. For this I chose an LT1303 DC/DC step-up converter, but any similar converter will do as well. Switching between applying +24v or -24v to the solenoid is achieved by using some MOSFETs. I can't use small BJT transistors because they won't handle the large impulse current through the solenoid (as high as 5A). Darlington transistor would work but I prefer MOSFETS for their power efficiency.

Tuesday, August 24, 2010

Black on Orange LCD Display

We received our Black on Orange 2 line 40 character LCD display from, and are soldering pin headers on it so we can mate it to our breadboard. This unit is the display module for our HVAC Controller / Weather Station. We still need the Humidity / Temp module and the Barometric Pressure Sensor if someone wants to help with the project. All schematics and code will be posted.

Solar panel monitor / logger

Hackaday has a cool post on Ladyada's video on solar charge control analysis.

The unit itself is built around an Arduino and can log the statistics to an SD card, show battery voltage, panel voltage, and current from panel to charger. You can see in the video above how she uses this to refine her design in real time for optimal results.

Monday, August 23, 2010

Remember Pong?

Here is a nice Arduino implementation of the old video game pong from the 70's!

More info:

Sunday, August 22, 2010

An Arduino Compatible Web Server for £12

Our good friend Ken Boak has been busy:

In the last 2 weeks I have been working towards making a very low cost Arduino compatible web server based on the ATmega328 interfaced to an ENC28J60 ethernet controller.