Tag Archives: kit

Ultrasonic Anemometer Part 28: New hardware tested

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I last time proudly presented the new RevB board and got a lot of feedback from people who want one, too. As mentioned I have all the components here to ship up to 10 kits but I was reluctant to send anything until I had the chance to do some hardware testing. Not much had changed since the last revision but I don’t like taking chances on things like this.

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In the mean time I managed to do some rudimentary testing and now feel confident to take orders. These tests concern the hardware only. What I said last time about the state of the software still applies. But let me tell you what I’ve been able to test so far.

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Tests performed so far

  • The PIC32 can be programmed from a PICKit3 via the ICSP header without any issues.
  • Power consumption is as expected. Like the previous version it draws 45mA@12V (programmed) and the other two rails come up with +3.310 and -3.279V, respectively. Also as expected. Regulator stays cool.
  • With the PIC controlling the AXIS, DIRECTION and SIGNAL pins, the transducers receive the 12V signal from the mosfet drivers. HOWEVER: the signals AXIS and DIRECTION are incorrectly labeled both in Eagle as well as on the silk screen. Electrically everything is fine but the names have been confused.
  • The signal from the transducers is properly received (Rec pin on the board) and amplified by a factor of 11 by the first stage of the amplifier (S1 pin on the board).
  • The PIC is able to control the digipot over the internal I2C bus and the second amplifier stage also performs as expected.
  • The zero-crossing detector (ZCD) works.
  • The input to the PIC’s ADC (ADC+ and ADC-) look fine, too. HOWEVER: the labeling on the silk screen is wrong. Eagle is correct, it’s just the silk screen. Plus should be minus and vice-versa. Again, electrically everything is fine.
  • The PIC can communicate (as a slave) with an Arduino UNO connected to the external I2C bus.
  • Communication over USB to a YAT-terminal under Win 7 works.

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The following has not been tested so far

  • For my tests I still used the transducers already used previously. I believe the ones I ordered last week are of the same type but I haven’t tested them.
  • EEPROM. I haven’t tried the newly added memory yet. I have confirmed that it has power and is connected to the same bus as the digipot so I have no reasons to assume there are issues with it. But testing it would require some software first.
  • The external SPI bus has never been tested, neither on the Rev A board nor with the new one. I don’t expect any problems but I haven’t done any testing so far.

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Is there anything important that I forgot to mention? In that case just ask.  A lot still needs to be done but at this point I’m confident that the board has no major flaws and performs much like the prototype.  Want to give it a try? I have some kits left for you.

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Continue here to the next post of this series.

Ultrasonic Anemometer Part 27: Ready to take pre-orders

20160903_StandaloneAnemometer_001Good news: the boards from dirtypcbs.com have arrived and look great. I also got all the components for the 11 boards. Why 11? I ordered about 10 (they call it a protopack) and was lucky enough to get 11. Thats dirtypcbs.

Last week I also upgraded my hobbyist Eagle license to a proper Premium LS license which means I can now legally start selling stuff. So I’m basically ready to ship the first kits.

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Today I assembled one of the boards and it at least looks great. All the footprints are correct and it was a pleasure to solder. Now what I want to do is to run some tests with it just to make sure it works as intended. I didn’t change much since the last version but I want to be sure first.

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About the kit

There’s one thing I want to be absolutely clear about. At this stage of development the wind meter is not yet ready to be deployed. While I think the hardware is final now, a lot more work is needed to get the software ready. So for the time being this kit is intended for people who want to join the development and testing. I’ve done most of the low-level, register-fiddling stuff but much remains to be done at a higher level. I know there are a lot of people out there with much more experience in signal processing than me and I’m looking forward to work on this challenge together. And a challenge it is. But the PIC32 still has plenty of RAM, Flash and CPU time left to try out new ideas and approaches until we find one that works well.

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The kit contains the board and all the necessary components. Details can be found in the BOM linked on the overview page. Once assembled it should look precisely like on the photos on this page. But as the name suggests, it comes as a kit, i.e. as components that you have to solder yourself. Most components come in relatively large SOIC packages but there are a few smaller MSOP and SOT-23 packages as well. They can all be soldered with a conventional soldering iron and strain solder just like I’ve done today.

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The microcontroller is not yet programmed so you will need a suitable programmer. Microchip’s PICKit3 (USD47.95) is the obvious choice here. This is also what I’m using and matches the board’s pinout. All the software (MPLAB X IDE and XC32 compiler) are available for download from Microchip free of charge.

Taking pre-orders now

I’ll start taking pre-orders now but as mentioned I won’t ship the kits until I’ve done some tests with my own board. Once that’s done I’ll let you know and if you’re still interested by then I’ll give you my PayPal details and ship the kits.

Some have mentioned that they already have some ultrasonic tranducers and/or want to try some specific model so you are free to order your kit with or without the transducers.

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There’s no online shop or anything like that so just use the contact form on the about me page.

Pricing

Now it starts getting interesting. I’ll quote all prices in USD, EUR and CHF.  Choose what’s cheapest or most convenient for you.

  • Kit without transducers: USD 70 / EUR 63 / CHF 69
  • Kit with transducers: USD 95 / EUR 85 / CHF 93

The prices above include worldwide shipping. The kits ship by Swiss Post Priority Mail in a padded envelope.  I’ve used this service before to locations like Brazil or India and never had problems. However, there are no tracking numbers.

Any other questions? Just ask.

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