Servo - May 2009

Volts reader, you probably know by now that I enjoy building small stripboard circuits, especially PICAXE programming adapters. (If not, as a TankBot owner you might want to check out the bi-monthly “PICAXE Primer” column in Nuts & Volts – several of the projects we have done there could easily be adapted to robotics experimentation.) Since a programming adapter can save some space on a breadboard circuit (or any circuit for that matter), I decided to make a small programming adapter (Prog03) specifically suited to the TankBot. Not only does it free up more breadboard real estate in our current TankBot project, it will also come in handy in many future projects, as well. The April 2008 installment of the PICAXE primer in Nuts & Volts presented the details of stripboard circuit construction and there isn’t enough space here to include all that information. After reading the following section, if you decide you want to construct the Prog03 adapter it would be a good idea to check out that issue of N&V.

I used a piece of software called “LochMaster” (German for “Strip Master”) to design the top and bottom stripboard layouts shown in Figure 3. As you can see, it’s a simple board that includes the three resistors (180 ohms, 10K, and 22K) needed for the basic PICAXE programming circuit. The black component on the right is a three-pin male header that I’ll describe shortly. What you don’t see in Figure 3 is the female DB9 connector that gets soldered to the left edge of the board. I didn’t include it because there was no suitable graphic in LochMaster. However, when we get to the actual construction of the Prog03 adapter, I’ll include photos that will make clear what is required.

Except for the female DB9 connector, all of the necessary parts (including the stripboard) are available on my website ( www.JRHackett.net).

Figure 1. Modified IR Echo Project Schematic.

The required female DB9 connector is the type that includes what are called “solder cups,” which means that wires can be directly soldered to the back end of the connector. If you don’t already have one on hand, this type of connector is commonly available (e.g., www.allelec tronics.com part #DB-9S or www. sparkfun.com part #PRT-00110).

There are a couple of ways to cut the strips as needed on the bottom of a stripboard. The details are covered

in the PICAXE Primer article mentioned above, but for the Prog03 board all you need is either a 1/8” (or 5/32”) drill bit or a sharp hobby knife (and a steady hand). The easiest type of cut to make (and the only one required for the Prog03 board) is one that can be done at a hole in the board (as opposed to cutting the trace between two holes). To cut a trace at a hole, all you need to do is to hold the drill bit between your