Repost: Martin's PPM tester
Posted: 10 Mar 2019, 12:48
Phil: This was another one of the many projects lost when 'reunited' was unexpectedly closed - I dont have a backup and I cant find anything on Wayback, so this is an attempt to recreate it.
In operation its similar to my own PPM tester in that it displays all the pulse widths generated by an encoder, but each has its own advantages - pick the one that suits you (or build both!)
Mine has a large backlit LCD display and optionally can drive servos directly from the PPM, and can also display individual PWM channels (ie a servo signal) from a receiver. Martins is a handy pocket-size using a small but very clear OLED display which includes an oscilloscope type waveform display of the channel pulses, which is really neat. Either one is a handy workbench tool, well worth having - I use both!
Martin's code was also incorporated into Ron's transmitter battery meter, its small enough to fit all but the tiniest of transmitter front panels.
So this is Martins PPM tester project. It uses a 5v Pro-Mini, Nano or anything similar, and just a few connections. Note that the Pro-Mini needs A4 and A5 - some early ones didnt have either. If you use one of the early Deek-Robot or DIY-More printed-circuit boards, remember that they have A4 and A5 annotations reversed. The display is a 1.3" OLED from ebay, for example https://www.ebay.co.uk/itm/1-3-inch-Blu ... 3393681269
With this arrangement the tester is powered from the encoder, ie via the pos of the incoming PPM connector. Of course it could be self-powered by (say) a single lipo cell (4.2v) in which case connect switched positive to Vcc on the Arduino. Leave Vin (sometimes called 'raw') disconnected, and also disconnect the red input wire from the PPM connector, leaving just the neg and signal pins.
I havent shown any protection on the PPM input - Martin used a series 10k in the incoming PPM line and also a 100n capacitor. I didnt bother as I use mine only for testing encoders which are 5v so in my own case, no protection is necessary.
Here's Martin's tester connected to the PPM output of one of my Single-Channel encoders - this particular example is generating 4 channels of negative-going PPM in JR channel order:
Mine is mounted in a small, clear plastic case, the sort you get with posh motors or servos.
Here it is on the left, alongside my 4-line and 2-line testers, sorry its dark but I have great difficulty photographing displays...
Cheers
Phil
In operation its similar to my own PPM tester in that it displays all the pulse widths generated by an encoder, but each has its own advantages - pick the one that suits you (or build both!)
Mine has a large backlit LCD display and optionally can drive servos directly from the PPM, and can also display individual PWM channels (ie a servo signal) from a receiver. Martins is a handy pocket-size using a small but very clear OLED display which includes an oscilloscope type waveform display of the channel pulses, which is really neat. Either one is a handy workbench tool, well worth having - I use both!
Martin's code was also incorporated into Ron's transmitter battery meter, its small enough to fit all but the tiniest of transmitter front panels.
So this is Martins PPM tester project. It uses a 5v Pro-Mini, Nano or anything similar, and just a few connections. Note that the Pro-Mini needs A4 and A5 - some early ones didnt have either. If you use one of the early Deek-Robot or DIY-More printed-circuit boards, remember that they have A4 and A5 annotations reversed. The display is a 1.3" OLED from ebay, for example https://www.ebay.co.uk/itm/1-3-inch-Blu ... 3393681269
With this arrangement the tester is powered from the encoder, ie via the pos of the incoming PPM connector. Of course it could be self-powered by (say) a single lipo cell (4.2v) in which case connect switched positive to Vcc on the Arduino. Leave Vin (sometimes called 'raw') disconnected, and also disconnect the red input wire from the PPM connector, leaving just the neg and signal pins.
I havent shown any protection on the PPM input - Martin used a series 10k in the incoming PPM line and also a 100n capacitor. I didnt bother as I use mine only for testing encoders which are 5v so in my own case, no protection is necessary.
Here's Martin's tester connected to the PPM output of one of my Single-Channel encoders - this particular example is generating 4 channels of negative-going PPM in JR channel order:
Mine is mounted in a small, clear plastic case, the sort you get with posh motors or servos.
Here it is on the left, alongside my 4-line and 2-line testers, sorry its dark but I have great difficulty photographing displays...
Cheers
Phil