Isolated PWM output

Facing the challenge of making an isolated DAC output I found a circuit by Kerry Wong (http://www.kerrywong.com/2013/10/01/an-isolated-dac-using-pwm-output/). Unfortunately, it did not work as I hoped. The optocoupler I used, a PC817 turned out to be too slow. It took some 20 us for the transistor to get out of saturation. Continue Reading

SIM900(A)

Did you struggle with a SIM900A module from ebay? Well, I did. I bought several from different vendors and spent some time to get them ‘online’ (or rather ‘on the air’). For a data logging project I bought 2 SIM900A modules. After I received them I found out that I Continue Reading

Aciera F450 Conversion

Back after a long period of silence. I started rebuilding the control system of an Aciera F450 milling machine. Originally the machine was fitted out with a Fanuc CNC controller. After someone pulled some boards for cleaning, the controller went dead. Why would anyone store the firmware in battery backed-up Continue Reading

Switch Mode Power Supply

Just a short little project I completed recently. A friend of mine was setting up a small PC to use on his sailboat and needed a power supply for it. The computer needed 2 amps at 5V. A linear regulator would have been easy to construct, but since on a Continue Reading

YAMAHA Manuals

Finally someone found me some manuals for the YAMAHA robot. A quick scan however did not reveal the presence of a ‘Compile’ instruction. Since I do not have the programming terminal, which should be part of the system, the only way I could make the thing move was to issue Continue Reading

DRO

I recently completed a Digital ReadOut for a lathe, using an AVR microprocessor and incremental encoder bars. You can find details here. Simple encoders with reasonable resolution (at least for hobby mills) can be found in old printers.The ruler which can be seen in this disassembled HP deskjet was taken Continue Reading

Programming the YAMAHA

I finally got the bastard to move. I started to write a ‘Control Interface’ in Delphi, with some predefinded commands. I really got tired of having to retype commands in Hyperterminal all the time. the Delphi program takes care of start- and endcodes and has a growing number of commands Continue Reading

Yamaha robot

The next thing I wanted to achieve of course was to see something moving. After getting rid of the ‘interlock’ fault message I got a new one. My new pal lost his mind and only responded with ‘Feedback error’, which drove me nuts for a while. I tried to disconnect Continue Reading