In my spare-time I like to bike. Since I live in a region with lots of hills, I built this little device to see how steep the road really is.

In my spare-time, I like to bike. Since I live in a region with lots of hills, this takes quite a lot of energy, many times resulting in a lot of sweat…Sometimes more, sometimes less. What I wanted to know, if there’s a relation between the inclination and the amount of sweat. So I built this little device, which measures the inclination and represents it at an old mobile phone-LCD. Unfortunately, measuring inclination is principally the same as measuring acceleration. So, the display was constantly changing, depending on the momentary power I produced on my pedal. The solution was found in computing the rolling average. Measuring the inclination is done by an accelerometer-chip, the SCA600, produced by VTI-Technologies. Calculations and controlling the LCD is done by a PIC 16F88 microcontroller from Microchip. The PIC also produces the negative voltage for the LCD. The unit has an auto-shut-off function. If the measured inclination has changed less than within 5 percent during 20 minutes, the unit is switched off (RB2). The (dirty!) program is written in assembly. The device is built in a small plastic box and clicked on the bar of my bike using a tool-clamp, see the photo’s. If I had to design it again, I would use a couple of penlights and a LDO regulator.