Let's Make Robots!


The most peculair behaviour, with Serial vs. without Serial.

Recently I came across the RFM70 2.4Ghz RF transceiver module and decided to buy 4 of them [at 3 EUR a pop, why not?]. The module talks SPI, has an IRQ pin too to indicate it has received data, so that's pretty useful for that low price!

I found some bits of code to interface with it: the producer of the chip published some example code and some people wrote libraries around that, which in turn I did myself too, using what was available on the web...

Cutting the pieces, and putting them together

2 kilogrammes of various colours of plexiglassAfter waiting longer than expected (some issues during transit) I finally received my batch of plexiglass a few days ago. While waiting for it, I used my time to carefully design the body parts in a CAD program.

Designing the new body for my robot...

The first robot that I have ever made currently has a cardboard body. As one can imagine, cardboard has its limits, both in durability and aestetics..  So the last few weeks I decided to look around for another material... I wanted something that is relatively easy to form and work with and not needing a whole set of new, special, tools... I came across plexiglass as an alternative and my choice was quickly made.

avr-size is quite a useful tool...

I was pulling my hairs out over unexplainable crashes yesterday, occuring on a Motoruino board.

It occured after simply enabling some more debugging stuff and it started to act all weird: crashing randomly and corrupted serial data.

It really had me going nuts at some point -- even wondering if the chip was bad. All until I read some interesting stuff about the .bss and .data size having limits. A shame that the  Arduino IDE does not check for the allowed sizes for SRAM.

The following command can easily reveal my problem:

Serial cable question...

Hi guys,

I would be grateful for some advice. Recently, I've read some articles about using a phone data cable to connect *duino's to the serial port of a PC. As I have a board without USB and a lot of old phone data cables, I thought hacking an existing cable could be a relatively cheap solution.

From what I gather, something to do with voltage levels, you cannot connect an Arduino to RS232 directly -- you need either electronics to regulate that, or an IC like the "MAX232". So... I started checking my old data cables for this chip, or a similar one.

Bump into things -- but in a very straight line!
Using a
I am building a very simple skid steer bot. I am still in the "prototyping" phase and its body is currently made of recycled cardboard boxes. After unpacking any … Read more