Jason - I have used both JMRI and the Infrared Red throttle that I built up a few weeks ago. I did have the current monitor fed back to the Arduino - you might also try changing the value of the CURRENT_SAMPLE_MAX variable in the CurrentMonitor.h tab from 300 to something much smaller. Might help. dave
I've just watched hardware video #3 in the hope it would clear up a long standing confusion of mine regarding how to create a bi-polar signal from a 5v logic signal but I still don't get it. The motor driver puts out +vin on one output pin and gnd on the other depending on the direction pin. Say +vin is 18v. We assert the direction pin and get +18 on rail 1 and gnd on rail 2. Then we clear the direction pin and get ground on rail 1 and +18 on rail 2. But we're still only swapping between +18 and gnd. The voltage between the rails is always 18v. Shouldn't the voltage between the rails be 36v? Regards, David.
The absolute voltage is always 18v. What makes it bipolar is that it changes direction so that the current direction reverses. In a unipolar signal the voltage would toggle from 18v to zero.
I've been playing with the ESP-8266 chip (a 3.3V component) that was mentioned in another thread and some of the motor drivers I have. The OSEPP L298N driver works without a hitch when fed 3.3V logic. The 43 Amp H-bridge described here, unfortunately, does not, even though it works fine with 5V. I say unfortunately because I was planning to use in my next project for my Freemon-compatible modules (it's the only motor driver I have that can read current). I thought I'd share this if someone was planning to use it with a 3.3V component. Now that I'm mentioning this, I wonder if I fed it 5V VCC from the power supply, and 3.3V control signals from the chip (PWW and EN), if that would make a difference. I guess there is only one way to find out. If not, perhaps I should use an inverter. Or the transistor trick?
You are half correct it is +18 on rail 1 and ground (or 0 volts) on rail 2, then switched and ground on rail 1 and +18 on rail 2, these are both DC voltages if your meter is fast enough it will show 18 volts and the + positive and - negative symbol will switch back and forth really fast OR if you have the meter in AC mode it will show close to 36vac but its not AC it is a bi-polar DC voltage.
A level converter is used for that its basicly transistors and resistors with two control voltages. This is just the first one i came across on ebay. http://www.ebay.com/itm/IIC-I2C-Log...205078?hash=item1c5fe93c16:g:tdEAAOSwoydWm~P- *also note if you are getting a 5v analog signal back from the h-bridge to the esp8266 you will need a voltage divider to safely use the 5v signal in the 3.3v esp8266
Hello I was browsing ebay in search for a motor shield and i came across this one: http://www.ebay.com/itm/VNH2SP30-St...835818?hash=item4aed00d9aa:g:XO4AAOSwjVVVnzzO It claims to deliver 30A power, and to be a replacement for L298N. Would this work directly or with some modification, or not at all?
Kim - we have experimented with this board before and had no success - it appears that the chip that it uses will not accept the high speed toggling of the direction that is used to create the DCC signal - if you search "Monster Moto" on TrainBoard you will find the discussion. dav
thank you David. What a shame, perhaps the 20khz frequency limit, of the chip, is inadequate? I will try your solution with the external booster instead, I don't mind the soldering anyway
Kim - it is not the PWM limit (20 khz) but the time needed to reverse direction - see table 9 in the data sheet. It is too bad as that is a nice board..... The 43 amp H-Bridge doesn't have to be used as a booster - there are notes on my web page to put it right on the DCC++ Uno - see: http://www.trainelectronics.com/DCC_Arduino/DCC++/index.htm#High_Power_H-Bridge_on_a_Shield dave
I have bought this one but as yet have not had any time to test it, by the info i have it looks like it will work. It is NOT a shield but close in size to a shield. http://www.ebay.com/itm/111140003697?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT If things ever settle down i will test it, wife ripped the cross link off the rear end in her 4 runner so now i get to play community vehicle game on top of the radio world stuff an others.
I have one of those boards and, while it can be made to work with DCC++, it does not have a current sensing output that can go to the DCC++ controller. This means that a dead short will not shut the controller down. I current sensor could be added as could a fuse but there is nothing built in. Sad as that is a really nice board. dave
I was going to use one of the ACS712T set for 10a - 15a as a short detector and use a separate 298p for programming, or a buch of acs712's as blocks and detect shorts at 4a - 8a range.
Is a PC power supply suitable for use as the power supply for the motor controller board? Using say the 15v part of it?
Kk Yes that is entirely possible, but some PSU's are dependent on a load for stable operation, 3A or so. I have one in my bench setup that I have modified so I can control the voltage output, from 3V to 40V a much cheaper solution than a lab PSU. If you can test without load first and then while you add load, to make there is no voltage drop, then you can determine if it is capable. Kim
Has anyone looked at this board for a motor shield? http://www.rugged-circuits.com/rugged-motor-driver Rugged Motor Driver The Rugged Motor Driver Shield for Arduino is a motor driver for two brush DC motors or one bipolar stepper motor. Rated for 30V and 2.8A peak current operation, the Rugged Motor Driver is the solution for powerful motion. The shield is directly compatible with the Ruggeduino, Arduino Uno, Duemilanove, and Mega, or can be used as a standalone motor driver with any microcontroller board. Please visit the Product Page for purchasing information. Features Operation from 8V-30V and 2.8A peak per phase This is the most powerful and rugged motor driver in its price class. Using two Texas Instruments DRV8801 2.8A H-bridge IC’s, the Rugged Motor Driver outperforms drivers based on the L298 (like the Arduino Motor Shield) and L293 (like the Adafruit Motor Shield). Take a look at the datasheet parameters: ParameterL293DL298DRV8801 Peak DC current per phase0.6A2A2.8A Overtemperature protectionYesYesYes Overcurrent protectionNoNoYes Shorted motor protectionNoNoYes DMOS constructionNoNoYes Synchronous rectificationNoNoYes Electrostatic discharge protectionNoNo2000V
Would work good for smaller scales than HO Scale I believe...I use the Pololu motor shield for HO Scale
