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Selecting microcontroller for hobby projects - opinions wanted.
I do not want to highjack another thread , but would like to hear some group comments on selection of microcontrollers for projects.
After reading some comments here I feel it is a time to ditch my controller and go for something new. Basically my old controller was a stand alone circuitry with flaky serial interface and programmed in flavor of Basic. I have been looking to add USB ?breakout? circuit but now I realize that there are devices on market with USB and other interfaces build in , can be programmed in C and with plenty of memory. However, in past I have been unlucky to pick a device which did not became popular ( 3 varactor diodes in one IC, single (!) bit microcontroller etc.) and were soon out of production. I am seeking group opinions on what microcontroller works for you and which one did not. Vaclav PS I am not sure if we can avoid ?plugs" by not naming vendors and still have reasonably accurate discussion here. |
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Re: inverter
--- In Electronics_101@..., Kirk McLoren <kirkmcloren@...> wrote:
A battery powered radio will be a lot cheaper. There are some inverters that claim to be pure sine wave here: About $650 ought to cover it for a 2 kW unit. Be aware that many inverters won't handle high inrush loads. Google for 'true sine wave inverter'. Richard |
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Re: USB I/O device
RS-422 (single TX, multiple RX) or RS-485 (multiple TX & RX).
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Balanced lines are much better than RS-232 though I have used RS-232 for decades. Other balanced line technologies could work. Network technologies clearly work and they are balanced lines. CAT 5 or 6 cables are pretty cheap. Balanced lines generally radiate less and are less susceptible to external interference. Charles AE5EW --- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
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Re: Any chip or simple circuit to reverse 1.5V -5V DC motors ?
Thanks gentlemen for the good suggestions. I think the 2 co Latching relay is the simplest solution : 5 Volt Relay, Latching, 2 Form C (DPDT)
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From $0.86 / each from an internet merchant 'Memo trinics'. Anybody know whether they are trustworthy or not? --- In Electronics_101@..., "ppplll000999" <ppplll000999@...> wrote:
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Re: USB I/O device
--- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
Another way to do it is with mbed: All of the IO functionality needs to be programmed (in C or C++) and, of course, some command language needs to be implemented for communications with the PC. Basically, only connectivity exists. However, on the up side, you can add an ethernet RJ45 jack and the LwIP stack is already available. Now your gadget can be networked. You still have to do all the code as above but you talk to a TCP/IP socket instead of /dev/ttyUSBx mbed is unique: all software development is done with a web browser. The entire toolchain is out on the 'cloud' somewhere and you don't have to install anything. I suppose software could be developed on a smartphone as long as it has a browser. Watch the "Take The Tour" video. In less than 2 dozen lines of code the author creates an application with an RF ID reader and TCP/IP to send a tweet when a user arrives at home. VERY clever! BTW, the mbed appears as a mass storage device when plugged in to USB. The USB port also supports serial IO. Richard |
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Re: USB I/O device
Hello John,
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M ore information on IO-Warrior-56 and companion products. See: The IO-Warrior24 device is a USB 1.1 device, has 16 I/O pins and comes in a 24 lead DIL package. Because it comes in 24 pin DIL package it will be fairly easy to add it to a project. Data sheet for IO-Warrior24 and IO-Warrior40 Data sheet for IO-warrior-56 An alternate product is a Cost $62.00 Software for use with Linux is available. Howard On 1/28/2011 12:55 AM, John Eh wrote:
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Re: [SPAM] LED string current balacing IC
A suggestion:
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Howard On 1/27/2011 11:13 PM, sanmeeth wrote:
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Re: USB I/O device
I am a little confused with what you trying to accomplish.
Do you want to control devices (lights, relays etc.) from your PC? Are these devicces, or some of them, input devices to your controller - PC? Do you want to use USB as a "serial" link to your PC? ( You have mentioned need for a driver) It looks to me that you are building this "chain": I/O device(48V relay) - I/O device hardware interface(48V driver) - USB link decoder (microprocessor?) - USB link (USB to serial?) - PC USB port(serial COM port?) - PC controller(software). Vaclav |
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Re: USB I/O device
--- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
Another approach is the USB Bit Whacker. There are two versions: The second version has 78 IO pins so that ought to cover it! The firmware capabilities for the two devices are quite different. Notably, I didn't see any analog capability with the 32 bit version. It doesn't appear that either version has PWM built in. I suppose that's why it is possible, if not easy, to modify the firmware and command language. Just be aware that you can't stall the USB loop so your code can not use spin loops for delays. I have used the first version to couple a PS2 game controller to my laptop so that RoboRealm software sees it as a serial port. RoboRealm then sent various commands to a small robot. It was the only way I could see to get PS2 input to a PC and out to the world. I'm pretty sure I botched up the firmware to add SPI to accomodate the PS2 controller. Richard |
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Re: USB I/O device
Marc R.J. Brevoort
Hi John,
I've done something remotely similar to what you're trying to do using an Atmel ATMega8 (now getting obsolete- but more recent replacements will work). I bought myself a USB<->RS232 cable and hooked up the USART of the AVR to a FT232 chip to guarantee the right signal levels. At few dollars for the USB<->RS232 cable, you will not only save yourself most of the headache involved with trying to get USB working on the uC side, but also guarantee that drivers on the computer side aren't an issue. Having the hard part sorted out by the USB-to-RS232 cable seems by far the simplest solution to your needs. I did a USB MIDI interface at some point. It did work, and with slightly different firmware it would be recognized as RS232 port instead. I basically ported it to ATMega8 based on this project: However, it was a quite painful process to get it working. I'm assuming that the 16 ports you want are to control 16 lights rather than to control 16 virtual RS232 ports over 1 USB device? Best, Marc |
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Re: LED string current balacing IC
The closest thing I've seen to what you need is a TLC5947. Single chip, needs just a current-setting resistor, etc. Unfortunately they can only drive strings up to 30V (with a 5V supply). Maybe you can use your 55V supply and transistors to drive your strings with a chip like that.
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--- In Electronics_101@..., "sanmeeth" <sanmeeth@...> wrote:
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Re: LED string current balacing IC
Hi Sanmeet,
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I uploaded a typical simple solution to drive many LEDs in series with a constant current. Hope it helps. "HV-LEDconstantCurrent.asc.pdf" Kerim --- In Electronics_101@..., "sanmeeth" <sanmeeth@...> wrote:
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Re: USB I/O device
Great suggestions so far. I was hoping for a complete board. For the moment I just want a working PC I/O device. With an easy way to attach all of the wires. I am going to worry about the the rest of it and make my own board last. I screw the board(s) into the side of the project plug in the PC to the USB and start wiring it up.
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For the 48V Solenoid I was intending to use a 48V power supply with a Power Transistor (MOSFET) driven by the USB I/O device (one wire over)? PC Fires the Solenoid. It would be nice if it could fire it for n seconds rather than turn it on. For the light I was thinking similar to the Solenoid but the light would be powered by 9V or 12V. PC able to flick the lights on and off. For the contact switches I was hoping just to have two wires back to the USB I/O that when contacted would send a message back to the PC by USB. So I was really looking for good completely build USB modules and why you would pick module made by company A over company B. Since I want between 2 and 5 USB devices cost is an issue. thanks John On 1/27/2011 8:16 PM, Howard Hansen wrote:
You may want to consider an IO-Warrior-56-Mod. See: |
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LED string current balacing IC
Im looking for a LED string current balancing IC without success. Does anyone knows of such an IC and point me to the same or some manufacturer who might be manufacturing such an IC?
Requirement: I want to drive multiple LED strings @ 25mA. The LED string forward voltage is 50V to 52V. I would use a 55V power supply. The IC should be able to regulate current (25mA) through multiple strings using PWM. Long back, I'd seen such an IC from a chinese product. It didnt require any inductor/capacitor etc, but only one current setting resistor. I require a similar IC but couldnt find one yet. Anyone seen some like that? Sanmeet |
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Re: Working wiht plexiglasss - little off the subject
Thanks Randy!
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Roland F. Harriston P.d ** Randy wrote: I wonder, though, if it's just a matter of words having become generic, |
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Re: Working wiht plexiglasss - little off the subject
I wonder, though, if it's just a matter of words having become generic,
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specific to the UK or US? Polyethylene (US) is the same as polythene (UK), and then there's aluminum vs. aluminium. Obviously, from a business perspective, the trademark names would matter... but, surprisingly enough, Lucite's international website sings the praises of Perspex: Randy V. On 1/27/2011 5:34 PM, Leon Heller wrote:
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Re: USB I/O device
You may want to consider an IO-Warrior-56-Mod. See:
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It doesn't meet all of your requirements. But it does have 50 I/O lines, Linux software support and only a few simple lines of code to access an I/O pins. Howard On 1/27/2011 1:47 PM, John Woolsey wrote:
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Re: USB I/O device
--- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
If you go with the Ardino board discussed previously, you can easily partition your project and use two boards. That will require the host software to talk to 2 /dev/ttyUSBx ports but that's not a big deal. Another approach is to buy a USB->RS485 device and use the RS485 protocol to connect to MANY boards. You might consider the ROBIN protocol for this: As to the 48v stuff, you probably don't want to use a transistor. Consider instead, a MOSFET. With the transistor, you will have the problem that Hfe (gain) for power devices is pretty low. So, you will look at the Darlington drivers and find that they drop a bunch of voltage and dissipate a lot of power as a result. My favorite MOSFET for just about anything is the IRL540N: Check figure 3 to see how much gate voltage (Vgs) you will need for the current you intend to carry. If you use a 5V Arduino then you can add a 1k pullup resistor on the pin that connects to the MOSFET gate. This will be pretty slow turn-on so don't expect to do PWM in the high number of kHz. Slow turn-on implies a long time in the linear region which brings along increased I^2*R loss and excessive heating. If you really want to drive the MOSFEZT, find a MOSFET driver chip. It will dump a capacitor full of charge into the gate in a real hurry and the MOSFET switching speed will be much higher. You will probably change to an IRF540N but expect to need at least 10V of gate voltage. Richard |
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