A few months ago a friend of mine -car mechanical at profession- told me that he had problem with some car sensors. He couldn’t check, with a simple multimeter, if a sensor was working properly. I advised him to buy a LCD oscilloscope instead of a normal oscilloscope, because of its small size. The use of an oscilloscope is very helpful because you can see the waveform that is produced by a “healthy” in-circuit-sensor* and you can compare it with the waveform of a “suspect” in-circuit-sensor.
After that, he told me that this oscilloscope costs a “fortune” for him as he has a small car service shop. I offered to help him by designing and constructing a small, cheap and workable LCD oscilloscope for him.
*in-circuit-sensor is the sensor which is connected on a board (PCB) or it’s connected somewhere in the car. It’s not a disconnected sensor.
You can download the source code, hex, schematic diagram,PCB and picture of the circuit .
Step 1 Selecting the components
Step 2 Designing the schematic diagram
Step 3 Making the prototype
Step 4 Putting the components in order
The breadboard circuit was temporary. It was the time to make the PCB for my AVR oscilloscope. The software that I used to draw the PCB is the Sprint layout 4. It is a really easy-to-use, cheap and efficient software to make your own PCBs.
I made my PCBs by myself by using toxic chemicals. That’s why I don’t describe the procedure. It’s very dangerous. I suggest you to give the transparency that you will print to a professional to make the PCB for you.
For more Detail: Low speed AVR oscilloscope V2.00 (Is updated on 19 Mar 2011)