New Tamaduino Page, Side Gigs

As you can see at the top of the blog, I added a Tamaduino page. The page is an attempt to provide more context for the project and details about the different resources that form the foundation of this project.

In other news, I'm still waiting for the new circuits from browndoggadets.com.

In the mean time I'm keeping my self busy with some side projects:

• building a magnetic stirrer for my friends yeast-cultivation  
• constructing a digital neuron from an old 10x1bit DRAM chip

I'll add some pictures as soon as I get to it!

HP-0014B PRO Charge Controller Circuit Diagram

I spent some time mapping the Li-Ion charging circuit I purchased. As far as I can tell the circuit is a combination of the reference design for each of the integrated circuits - U2, U3, and U4 - and an RC filter. My guess is that the RC filter is supposed to keep the noise from the DC/DC converter from interfering with the current monitoring of the lithium cell charging IC.

The next step is to evaluate the best way to interface an ATtiny85 to monitor and control the circuit.

Datasheets:

U1: GTT8205S N-Channel MOSFETs

U2: DW01AM Lithium Cell Over- and Discharge Protection IC

U3: CE8301 Step-Up DC/DC Converter IC

U4: TP4057 Lithium Cell Charge Controller IC

Hardware for the Energy Brain

Most of these components were left over from other projects:

• 5V/100mA Solar Panel
• Plastic Project Box
• 1F Super-Capacitor
• Atmel ATtiny85 Microcontroller
• 3.7V 1120mAh Li-Ion Camera Battery

My experience building charge controllers and switching power supplies is limited. To save time I ordered this little circuit from browndoggadgets.com:

This 3.7V Li-Ion charge control circuit accepts 5V Vin and has an integrated 5V boost supply that feeds off the battery. My hope is to modify the circuit board so that the ATtiny85 uC can turn the 5V boost supply on and off as needed.