Comments for Mike's Lab Notes

Comment on ZX Spectrum on FPGA by Doug Barry

Doug Barry — Thu, 09 May 2013 19:27:05 +0000

That would be very useful Mike, thanks. Hopefully I’ll get time to do some work on it over the summer, I’m more accustom to the world of microcontrollers, but in order to keep up I’ve decided to have a crack at FPGAs. Something like this might be a bit above me now but you have to challenge yourself to learn.

Comment on ZX Spectrum on FPGA by Mike

Mike — Thu, 09 May 2013 15:36:30 +0000

I don’t see why not. You would need to update the pin assignments accordingly and then check for any changes to the clock tree. The DE0 doesn’t seem to have any SRAM, so unless there is enough spare RAM in the FPGA to make up for it you might have the pain of writing an SDRAM controller.

I’m thinking of putting the Speccy and BBC VHDL on GitHub, to make it easier for people to do forks like this. Will aim to get that done over the next couple of days if that would be of use to you.

Mike

Comment on ZX Spectrum on FPGA by Doug Barry

Doug Barry — Thu, 09 May 2013 15:24:23 +0000

Hi Mike,

Would it be possible to port this to the DE0 board?

At first glance the differences between the DE0 and DE1 that may affect it are the DE0 has a Cyclone III, but doesn’t include a Line in/out.

I’d love to give this a go, having recently sold my spectrum hardware and thought I could make do with emulation. Its just not the same I already have a DE0 spare from another project.

Thanks.

Comment on A Simple RF Protocol (or, what is the point of ZigBee?) by Felix

Felix — Tue, 07 May 2013 21:30:06 +0000

Sure thing, I’m very interested, please let me know when you start work on a lib – I got some RFM69W samples already (I like them already) but have been super busy trying to keep up with my blog and store so I haven’t played with them yet – mostly because I couldn’t find AVR code for it and was planning on starting work on a lib myself. However it seems like a more complex radio than the RFM12B which was rather simple to interact with.

Comment on A Simple RF Protocol (or, what is the point of ZigBee?) by Mike

Mike — Tue, 07 May 2013 21:18:48 +0000

Hi Felix,

I am actually awaiting samples of the RFM69W and will probably switch to those from RFM23B if it works out. The new modules have similar capabilities to the RFM23B, so the only potential problem will be minimum supply voltage, which at the 2.4V given in the datasheet is a bit high for battery powered nodes. However, the underlying chip also comes in a low-power version that goes down to 1.8V and would still meet the spec of the RFM69W, so I am hopeful that they used that in the non-H version of the module.

I expect to start working on a protocol in the next few weeks, aiming for some amount of interoperability between at least RFM23B, RFM69W and probably Ciseco SRF. Crypto and authentication will be built in, which the RFM69W and SRF would be good at. If you are interested in collaborating I’ll get in touch once I get started?

Mike

Comment on A Simple RF Protocol (or, what is the point of ZigBee?) by Felix

Felix — Tue, 07 May 2013 20:56:44 +0000

Hey Mike, I share the interest in a small footprint stack that would satisfy the requirements you mentioned. I’be been working with RFM12B for some time and even came up with my own version of a library for it (see website); I’m looking at RFM69W as an alternative due to rumors of RFM12B’s EOL – although there’s no library for it that I know of yet. But the specs on the RFM69W look real promising… 13dbm max TX power (vs 0dbm on the RFM12B).

Comment on Low Cost, High Accuracy Temperature Sensing with a Thermistor by Alex

Alex — Tue, 30 Apr 2013 03:46:17 +0000

Interesting.

I’m planning something similar for my project.
Except I’m using even cheaper thermistors and resistors (5% ones) and generating a custom LUT for each of them using curve fitting.

Comment on Low Cost, High Accuracy Temperature Sensing with a Thermistor by Low Cost, High Accuracy Temperature Sensing with a Thermistor - Home Brew Forums

Low Cost, High Accuracy Temperature Sensing with a Thermistor - Home Brew Forums — Mon, 29 Apr 2013 21:04:17 +0000

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Comment on Implementing the ELV FHT Protocol with an RFM23 by Mike

Mike — Tue, 23 Apr 2013 16:38:30 +0000

Yes. It has space on the board for a TI TMP112 or TMP102 digital sensor, or you can use a thermistor, which is much cheaper and almost as accurate. You could certainly use a Pi and suitable RF module as a receiver.

Comment on Implementing the ELV FHT Protocol with an RFM23 by Jiri Tlusty

Jiri Tlusty — Tue, 23 Apr 2013 16:07:45 +0000

Thanks for the prompt answer, since the winter season is over I surely can wait for the results of your RFM69W investigation.

By the way, is your sensor board usable as a remote wireless temperature sensor equipped for example with Dallas DS18B20 (in my case, using Rasbperry Pi + FM23B-like module to read the data)?