Picture shows my new (just had it made in China) Netburner MOD5270 carrier board. It offers a 16bit I/O expander, all the MOD5270 GPIO, two serial ports, 4 channel 16 bit A/D, 6 500ma relay drivers (ULN 2803A), and 16 servo (or PWM channels). Two of the 2803A channels are driven from 3.3V and will operate LEDs and loads under about 50ma. https://www.youtube.com/watch?v=4Tx6jJKtteo
Above video shows generation of DCC (Digital Command control) model railroad signals with a Netburner. It also shows the web interface buttons. https://www.youtube.com/watch?v=DaRNY7TQXI0
This one shows the same H bridge stepping a stepping motor. https://www.youtube.com/watch?v=fJLCv6pa2pM
Above shows control of a servo, you can control 16 of them if you want. This uses a gamepad to control the servo. This is just a brief demo - much more is possible.
https://www.youtube.com/watch?v=DWnkZP2olU0
This video shows my Netburner MOD5270 carrier board controlling an "Ad Hoc" RC servo from a web page. Since RC servos are not that powerful - I designed a circuit board that mounts on a $2.25 Ebay L298 H bridge module and forms a more powerful servo driver. The servo is made from a gear motor and a multi turn 5K feedback potentiometer. One could also use an automotive wiper motor or any other variant of nominal 30 to 150 RPM gearmotor. I have a potentiometer that adjusts deadband to compensate for high inertia loads. Animatronics over the internets!
There is the Internet of Things and there is the internet of YUUGE 43 AMP things. Got a 43 AMP H bridge on E-bay and am using it to drive the gear motor servo. My servo to H bridge driver board is really an awesome device - I am naming it my invention of the month. Note that the rated maximum voltage of the bridge is 45 volts. That is a maximum load power of 1935 watts or 2.6 horsepower. I would conservatively apply it at 24V and 20 AMPS or .64HP. Video above shows DCC railroad operation, the servo drive, and the web page - and of course the web page communicates with the Netburner via both AJAX (servo position) and ordinary HTML pages with attached ?XXX parameter calls (locomotive).
This video shows my new MOD5270 carrier board in action - controlling the worlds only and greatest DCC Internet Model Railroad. I also demonstrate machine vision train control - no wires, no sensors, just one cheap analog camera and my machine vision circuit board (carries a MOD5213). It sends precise location data to the MOD5270 via RS-232.
Built a second example of my Netburner MOD5270 carrier board (the first one is now attached to the model RR) and in the above video I operate a wiper motor that I turned into a servo - I control it using a slide bar in a web browser. As previously noted I built a circuit board to provide logic drive to an H bridge and essentially make any gearmotor with a feedback potentiometer into a servo. The potentiometer drive in this example is kind of crude - I have since found a better way using Actobotics parts and that will be coming soon.
The servo control uses the M51660L servo chip shown in the pictures. It is usually applied to drive small model airplane RC servos and incorporates an H bridge with external PNP high side transistors as shown. I also show my modification in which I just use the lower half of the H-bridge (that is in the chip) with 1K pull up resistors to generate logic signals which can drive BTS7960B or L298 H bridges. The bridges are available on Ebay cheaper than you can make them. If you want bare or completed circuit boards I can make you a deal !
The bottom picture is the original - the top the modification. Ignore the Schmitt triggers - they were deleted.
Note that instead of the 1K resistor between pin 9 and 11 I use a 470 ohm in series with a 2K pot. This allows tuning of the deadband. The 5K pot is the feedback potentiometer driven by the servo motor.
Attachments
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servo-control-circuit.jpg (44.71 KiB) Viewed 12693 times
Monster wiper motor servo, using web slider control and my MOD5270 Superboard, lifts a 15 pound tool box from the end of a 3.8" arm! That is 900++ inch ounces and (probably) around 13 AMPS (I didn't have the meter on it but I have seen 12A peak starting with a big error signal). Servo city has one that is more powerful - but it costs $425. The wiper motor, this is the VW wiper motor, costs about $25 on Ebay. I think I originally said Dodge (I have a Dodge part and it is almost exactly the same) but this is the VW. The bridge is $11 and my circuit board is $40 if I make it. The potentiometer drive depends on your creativity - but that is a lot of power on the cheap.
You don't get a Netburner so you can put a picture of your dinner on a web page - Hostingplex or Facebook does that. A Netburner is best used to gather data and perform control action in the real world. And this board and it's accessories give you that capacity!
This video shows control of the Wiper Motor Monster servo using a Logitech gamepad in Chrome! The Internet of Things at your thumbs!
And don't forget - the Superboard would control 16 of these. Given some mechanical work you could throw balls to your dog while you are at work. Depending on your boss of course. I am retired so I don't have to worry.
