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  1. CDRIVE

    How to amplify a square wave cheaply?

    Google PA240U OpAmp data sheet. It's a HV/HP driver. Even includes a sample Piezo driver circuit.
  2. CDRIVE

    How to amplify a square wave cheaply?

    Oops! If your gen is outputting +- 10V you'll want a 1N914 on the base of the driver transistor. Connect the Cathode to the Base and Anode to GND. Most BJTs have a maximum Vbe (reverse bias) of 5V. The diode with protect it from exceeding -.7V when the gen goes negative. ;)
  3. CDRIVE

    How to amplify a square wave cheaply?

    We really need 'Permalink' on the forum and an electronics text editor. Heck, the posts aren't even numbered! :eek: I posted this earlier. https://www.electronicspoint.com/attachments/4436d1337830344-amplify-square-wave-cheaply-piezodriver.jpg Edit: Just lower the Vcc to 30V. ;)
  4. CDRIVE

    Digital Pot setup

    Justin here's my latest version of the DAC controller. After reading the Picaxe pdf regarding the DAC output it states that the 5v Vdd can't be achieved. The best documented results has been 4.78V. I doubt that a 220mV drop is going to be an issue but if it is there are ways of overcoming it...
  5. CDRIVE

    How to amplify a square wave cheaply?

    I just re-read this. I could be wrong, though I doubt it. Common Piezos (CYA) aren't meant to operate at low frequencies like your driving it with. They have a resonant frequency, where their output will be maximum; see my previous post. If you think the output is low now, try switching your...
  6. CDRIVE

    Digital Pot setup

    They'll work fine but a 78L05 would have worked too, while taking up about 1/4 of the real estate. Not a problem though because (currently) your project board has plenty of room. I'll stress "currently" because we're prototyping here. Live tests often produce contrary results to an untested...
  7. CDRIVE

    How to amplify a square wave cheaply?

    Harald, are you sure about this? I've tried it as you've shown but it produced very little drive to the Piezo. You're not providing a DC path for any Collector current. These are the two options I use. Chris
  8. CDRIVE

    Digital Pot setup

    Justin, I received your PM and I know you're in a hurry but we have to nail down a few things. This thread is so long that much of what may have been covered I've now forgotten and I don't feel like sifting though all the posts. So, here's some questions. I think you said that the motor and...
  9. CDRIVE

    Digital Pot setup

    1Meg is good news! Won't need a buffer. Chris
  10. CDRIVE

    PICaxe Vs PIC

    Ugh!! This is turning into debating for the sake of debating. :rolleyes: Keep an eye open for my future posts. I will probably repeat those quotes, without reservation. I'm a conservative. I don't waffle. :D Chris
  11. CDRIVE

    PICaxe Vs PIC

    I think Bob really boiled the water down here. In fact, it escapes me why there's even a debate. There is zero investment in Picaxe, less the cost of a chip. Everyone has spare serial cables, so there's no investment there either. For those without serial ports; just about everyone has a...
  12. CDRIVE

    PICaxe Vs PIC

    I have to be honest and say that this is not my first time stepping into the Pic-Picaxe ring. I'm more than willing to go the full 12 rounds. One thing always seems to be prevalent in these bouts. I know my opponents will deny it vehemently but I can't shake the impression of elitism. Much like...
  13. CDRIVE

    Digital Pot setup

    Justin, does the manufacturer of the motor controller spec the input impedance / Resistance of the 0-5V speed control input? This figure is rather important for the DAC output to work properly. If it's too low I'll have to add a buffer to the circuit.
  14. CDRIVE

    PICaxe Vs PIC

    Also keep in mind that Picaxe hasn't stood still. It's evolving and getting more powerful at a respectable pace. The 08M2 has a heck of a lot more memory and faster than the M parts and a SL more memory than the original 08 part. DAC didn't exist on the M part either. ;)
  15. CDRIVE

    PICaxe Vs PIC

    Thanks for the info.
  16. CDRIVE

    Digital Pot setup

    This starter pack includes the USB/Serial cable (AXE027) and driver software. http://www.picaxe.com/Hardware/Starter-Packs/PICAXE-Development-Starter-Pack/ Buy a few 08M2 Chips. They're cheap...
  17. CDRIVE

    Digital Pot setup

    Justin, The AX27 USB/Serial cable is an incorrect part number. The Picaxe server is down right now, so I can't get in to give you the correct number now. I'll post it when it's back up. Chris Edit: It's an AXE027
  18. CDRIVE

    Digital Pot setup

    gorgon, If I ever saw an exemplary example of the superiority of uC's over digital logic/analog blocks, this is it. It's a stellar and laborious effort though! I don't have that much energy! :D
  19. CDRIVE

    Digital Pot setup

    All Picaxe software is free except for PicaxeVSM. This is because it doesn't belong to Picaxe. PicaxeVSM is a Spice program copy written by ISIS / Proteus. It is not needed to program a Picaxe chip or write your programs either. Most PC's today don't have RS232 (Serial Port) interface to the...
  20. CDRIVE

    Digital Pot setup

    Justin, if you're running Windows then download this package. http://www.picaxe.com/Software/PICAXE/PICAXE-Programming-Editor The pdf manuals should be included in the distribution setup .exe. Chris
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