Eluke.nl

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  • USBisp V2.0 to USBasp conversion to use TPI (or: USBisp did not connect to usb anymore after fw update – fixed!)

    USBisp V2.0 to USBasp conversion to use TPI (or: USBisp did not connect to usb anymore after fw update – fixed!)

    Recently I bought an USBasp, or at least that’s what I thought. I bought a clone that was advertised as  “USB ISP USBasp USBisp Programmer for 51 ATMEL AVR download support Win 7 64 (RANDOM COLOR)”, marked on the case as “USB ISP version 2.0” and “MX-USBISP-V5.00” on the PCB. I intend to use this…

  • [fixed] TM1637 LED display “not working”.

    [fixed] TM1637 LED display “not working”.

    Last week I got 2 of these displays from a friend who couldn’t get them to display anything. (He knows I like those challenges.) Below picture proves it now works. What was the case: The data sheet says (e.g. in the schematic at page 8) a 100pF capacitor should be placed on CLK and DIO…

  • Fixed: RC522 RFID reader not reading (some) cards (Part 1)

    Fixed: RC522 RFID reader not reading (some) cards (Part 1)

    Some of the RC-522 RFID card reader modules that can be bought on ebay / aliexpress have a problem: they do not read all (types of) cards they should be able to read. In this blog post I want to explain how to recognize these faulty readers and how to fix them. (There is a…

  • How to enable Motion Detection Interrupt on MPU6050.

    The MPU6050 data sheet has a nice “marketing” section, claiming it has a DMP unit, and a couple of useful interrupts, among them a accelerometer event interrupt. However, how to actually use these features is not documented there. And I want to use the Motion Detection Interrupt (so I can put the host MCU to…

  • Fine motor skills?

    I did not know this was possible. The hollow core motors of a Cheerson CX-10 can actually be opened, and a new wire can be soldered to the brushes when the original one broke of. This started as a challenge, me stating it was impossible to open these motors without damaging them beyond repair and…

  • Python echo

    This adds a echo to a wav file. The file also gets louder, because the result is not normalized. (sample + 0.8*Othersample v.s. sample+0.8*Othersample/1.8). This is my first real experiment with DSP.  Maybe More Later(tm). Comments are welcome. (no registration necessary / pre-moderated by me) [sourcecode language=”python” wraplines=”false” collapse=”false”] """ Echo. Usage: python_Echo InpuFile.wav OutputFile.wav…

  • Continued “data transmission whistle” experiment, more successful this time

    Okay, what’s this about? Oona Räisänen challenged her readers to construct a whistle that could transmit data using FSK. And if one reads her challenge carefully it says “whistle”. Not “pea whistle“. Now THAT simplifies things a lot! A whistle design like this can be modified by inserting a magnet and wrapping a coil around…

  • (Failed) Pea whistle experiment

    Well, not really failed, since every result is a result. I just found a way how this does not work. Two in fact. Okay, what’s this about? Oona Räisänen challenged her readers to construct a whistle that could transmit data using FSK. So, I thought about replacing the pea in a pea whistle with a…

  • ATX computer power supply current limit.

    (This post is also available in Dutch) For another project I’m tinkering with an old computer power supply. While I’m at it, why not see if I can build some crude current limiting. It does not need to regulate the current neatly, as long as it is short circuit proof. A LED on the 12V…

  • Some short notes on the Lecroy9450 repair project

    Because there is no big news yet, some short updates. – Claude Schwarz pointed me to the Yahoo user group “Lecroy Owners group”, they have design files for a HHZ406 replacement. (Made by Dieter Frieauff). So maybe the ext. trigger input can be repaired as well. – A service manual for this ‘scope (And others)…

  • LeCroy 9450 oscilloscope repair

    This was supposed to be an easy repair, and therefore not worth blogging about. But as it turns out, it might get interesting after all. (The ‘scope is not repaired yet) The “Leidse Makerspace” owns a LeCroy 9450 350Mhz DSO. When they moved to their new location I temporarily got this oscilloscope. Not just for…