Jump to content
43oh

Xuan

Members
  • Content Count

    12
  • Joined

  • Last visited

  • Days Won

    1
  1. Implementing the host (master) side of one wire protocol is pretty simple, your code controls the speed and as long as you don't have really low speed, you should be fine. The tricky part is simulating the device side, which is what I'm doing here: I have to pull down the signal line in 10us otherwise the time slot will be invalid. Although I opened a broken dell laptop to get the dc connector, I didn't check what chip it's using on laptop side, maybe that's something I can do later. For PSUs, all dell PSUs, they have different amperage ratings, but the voltage is always 19.5v, and I notic
  2. What I found by listening the communication between laptop and adapter is that it only asks 3 bytes starting at address 8, which is "090" for my power adapter. This turns out to be the wattage and that's the only thing my dell laptop needs. It doesn't even care all the other information...
  3. This is all about learning OneWire communications. I'm able to make a small "adapter" playing the "man in the middle" hack between dell laptop and its power brick to provide "fake" wattage information. For me I'm using it to "fix" a power adapter which has a damaged identification chip. Of course it can also be used to use non-dell power adapter (on your own risk of damaging the laptop, or even burn your house, who knows...) All the code and pcb design can be found at https://github.com/HclX/DELL_POWER_SPOOFER.git and my http://hclxing.wordpress.com/2014/02/26/hacking-a-dell-power-adapter-
  4. You don't really need the external crystal. Getting rid of that can save you a lot of space which may allow you move your tactile button to an accessible location. Have you tested the range of your module? I'm working on something similar and found even with 250kbps it won't fully cover the whole range of my house in which case there are some bits flipping and I finally implemented an error correction algorithm to ensure max range with good quality.
  5. I actually made misakes with USB+ and USB-, but after fixing them, I still get nothing showing up. Is it possible that the chip got fried when USB+ and USB- were swapped?
  6. I created a simple USB to serial circuit using FTDI chip, however, the end result is not working at all. Can someone take a look at the schematic and let me know what's wrong with it? Some notes: 1. Nothing shows up in device manager on windows desktop after plugging in to USB port. 2. Nothing shows up in dmesg under ubuntu when plugging in to USB port 3. 3V3 out has correct output voltage 4. Both TXD and RXD shows 3.3v Any idea what may be missing? V1_HUB.brd V1_HUB.sch
  7. Talking about FTDI, I'm trying to add USB to serial functionality to my own board using the FT232RL chip with schematics from sparkfun(https://www.sparkfun.com/products/718). I've verified pin by pin no errors no soldering problem, but this thing just doesn't work. Nothing shows up in my device manager when I plugin the USB cable. I can get 3.3v output from the chip. Any idea what may be wrong?
  8. Nevermind, i found the problem: I was using wrong RF settings for 250kbps. It's working now.
  9. does the TI's value line MC support "long" type? 18202393 is apparently out of the 16bit word range.
  10. I'm trying to setup an RF link between two MSP430 launch pad using NRF24L01+ modules. It's working at some level but have very strange issues: 1. I'm currently configuring them working at 1Mbps/2Mbps and they work perfectly. However, 250kbps never worked correctly for me: I can receive data packet but I can never have a correct packet. There are always a lot of wrong bytes in the received packet. 2. Even strangely, if I configure the the receiver side to run at 1Mbps, and leave the sender running at 250kbps, I get better result: it's now about only 20% incorrect packets. Here are the
  11. Has anybody done the antenna modification thing? I replaced the PCB antenna with just a piece of wire and noticed the range increased by 2 or 3 meters indoor. However, I don't have knowledge of tuning the antenna wire length. Any tips on that?
  12. Xuan

    RF bootloader

    The idea is very interesting, but not sure if it's really necessary. I'm doing something similar but my system requires a running linux system as the "server", sensors just send information to the server and you can define actions and complex conditions on server side, using whatever advanced scripting language you want. It will greatly lower down the power consumption and cost of each sensor node. The server can be a raspberry pi, or even an arduino board.
×
×
  • Create New...