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by tony99
Wed May 01, 2013 7:00 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Update : RD3-oscilloscope, logic analyzer, pattern generator update A quick update on the progress we've made so far. 1 - 2/3 boards (power supply, and the main (FPGA/ADC/DAC) board) came in early 2 - 2/3 boards (power supply, and the main (FPGA/ADC/DAC) board) stuffed 3 - Power Supply for the FPGA'...
by tony99
Sat Apr 20, 2013 4:59 am
Forum: Automation, sensing and robotics
Topic: data logger
Replies: 5
Views: 3030

Re: data logger

Hi, We did a project called the RAS-DAS-1 which was a quick 8 channel ADC connected to the SPI bus of the Raspberry Pi - using an MCP 3008. It has an adjustable input voltage range, supports AC/DC coupling, and comes complete with input protection diodes. There is an oscilloscope and spectrum analyz...
by tony99
Sat Apr 20, 2013 4:45 am
Forum: Automation, sensing and robotics
Topic: How to read and store 200 digital inputs
Replies: 18
Views: 3583

Re: How to read and store 200 digital inputs

Yes, I think FPGA's can be very useful. (In fact, I'm using an FPGA for a raspberry pi based oscilloscope, but that's another topic ... http://www.raspberrypi.org/phpBB3/viewtopic.php?f=37&t=40299) I'm wondering, if it might make sense to have a general purpose FPGA board which you can connect to th...
by tony99
Sat Apr 20, 2013 1:34 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Quick Update Hi Everyone, Just a quick update. We just got our prototype boards from the PCB manufacturer. They came on a sheet of 12 : sheet.jpg Here are close ups of two boards (the FPGA/ADC/DAC card, and the power supply board). main_and_power.jpg These are surface mount devices with a 0.5mm pad ...
by tony99
Wed Apr 17, 2013 6:26 pm
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Hi Everyone, We've updated our web site, which shows a block diagram of the hardware system. http://www.wattminderinstruments.com/rd3_main (hardware info + block diagram) http://www.wattminderinstruments.com/rd3_apps (software info) http://www.wattminderinstruments.com/view/17 (project status info) ...
by tony99
Sun Apr 14, 2013 5:40 pm
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Thanks for the tip. Video applications have driven down the prices of these components significantly (I used to work in the video field a long time ago), so I will certainly look into this. Just be aware though that sometimes what you "see" isn't what you actually get. For instance, a lot of low end...
by tony99
Sat Apr 13, 2013 9:31 pm
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

That makes sense - then you essentially get an oscilloscope which is good to HF (30+ MHz, 65 MSPS) - at 10 bit resolution - with a tradeoff in price. As the FPGA increases in price pretty quickly, we might do an "A" and an "B" variant - one with just 10 bits/65 MSPS and the 3C5 and another one with ...
by tony99
Sat Apr 13, 2013 11:37 am
Forum: Other projects
Topic: Ham Radio
Replies: 5
Views: 9822

Re: Ham Radio

Wow - it's almost like you read my mind. I was putting this low cost (high value) solution together which interfaces to the Rasberry Pi (we're calling it the RD3). It is basically an FPGA with a high speed DAC and a high speed ADC. At first we're putting some simple applications on this platform : o...
by tony99
Fri Apr 12, 2013 6:26 pm
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Hi rurwin, Thanks for your reply. It sounds like you do want to have a little more resolution on the ADC itself. The ADC we picked (for our current board run) is the Analog Devices AD9288 (8 bit resolution). This chip is pin compatible with the Analog Devices AD9218 (10 bit resolution). So, it's pos...
by tony99
Fri Apr 12, 2013 9:07 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

hmmm detail vs bandwidth? We will have an analog front end board with selectable gain settings. This will allow you to zoom in on very small scale signals - just like most digital oscilloscopes. Would that provide the necessary detail? ... or are you saying that you need more than 48 dB SNR (that th...
by tony99
Fri Apr 12, 2013 8:57 am
Forum: Automation, sensing and robotics
Topic: General robotics questions
Replies: 11
Views: 1548

Re: General robotics questions

Would this work? http://www.amazon.com/Infrared-Proximity-Sensor-Gp2d12-Arduino/dp/B007YBB8U4/ref=sr_1_3?s=pc&ie=UTF8&qid=1365689001&sr=1-3&keywords=proximity+sensor That sensor is more suitable for a device like the Arduino which has analogue inputs. You can do a bodge job to get it working on the...
by tony99
Fri Apr 12, 2013 8:23 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

First thoughts are 8 bit A/D instead of 10 was a bad move, sure I understand the sample rate implications, but I would have chosen resolution over speed in that case. Hi aTao, What about we do some signal processing (low pass filtering) and reduction in sample rate reduction in the FPGA to provide ...
by tony99
Fri Apr 12, 2013 8:17 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

Re: oscilloscope, logic analyzer, & signal generator periphe

Hi rurwin, Thanks for your feedback. There is a plan for an analog input card with a programable gain input amplifier. The input is meant to look very much like an oscilloscope input - in that it will be selectable between 1 Mohm, and 50 ohm input (with standard BNC connectors). The analog front end...
by tony99
Fri Apr 12, 2013 6:29 am
Forum: Automation, sensing and robotics
Topic: oscilloscope, logic analyzer, & signal generator peripheral
Replies: 19
Views: 19035

oscilloscope, logic analyzer, & signal generator peripheral

Hello, I would like to announce that we (wattminderinstruments.com) are developing what I believe is to be a very interesting peripheral for the Paspberry Pi. The concept is a combination a 2-channel oscilloscope, running at 100 MSPS, a 2-channel signal generator (also running at 100 MSPS), and 16 c...
by tony99
Mon Mar 11, 2013 9:45 pm
Forum: Bare metal, Assembly language
Topic: Capturing High Speed Data on a Raspberry Pi
Replies: 1
Views: 1456

Capturing High Speed Data on a Raspberry Pi

The traditional approach is to try to use an interrupt, and capture data every interrupt. The primary issue is that Linux gets in the way, and it's possible that your interrupt request handler may get called some time after (I think up to 50us) the request. Using IRQ's and attempting to decrease thi...
by tony99
Tue Mar 05, 2013 3:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI Inaccurate readings..
Replies: 13
Views: 16505

Re: MCP3008 SPI Inaccurate readings..

Hi Manxam, Sometimes you might have a signal with a larger voltage swing than 3.3V. The MCP3008 is specified to run faster at VDD=VREF=5.0V (200ksps) vs VDD=VREF=2.7V (75 ksps). Also, if you look at the performance specifications, you will see that the INL, DNL, and all other specs are much better a...
by tony99
Mon Mar 04, 2013 11:56 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI Inaccurate readings..
Replies: 13
Views: 16505

Re: MCP3008 SPI Inaccurate readings..

Hi, FYI, MCP3008 is limited to 200ksps, and is quite capable of doing a good job at Analog-Digital conversion. The key thing is to make sure that you do not exceed the data rate - both minimum and maximum. This means that the SPI sample clock needs to be at least 10kHz, and at most 3.6 MHz. Stay wit...
by tony99
Mon Mar 04, 2013 11:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: National Instruments USB data acquisition driver
Replies: 7
Views: 14179

Re: National Instruments USB data acquisition driver

We'll ship to outside the US. Our main concern was with the power plug for the USB power supply. The RAS-DAS-1 card itself doesn't care about type of power it's getting (as long as it's 5V, it can come from the Raspberry Pi itself, or from an external power source). Tony (Wattminder Instrustruments)
by tony99
Mon Mar 04, 2013 2:06 am
Forum: HATs and other add-ons
Topic: Kickstart Campaign for an Analog Data Acquisition Card
Replies: 0
Views: 1857

Kickstart Campaign for an Analog Data Acquisition Card

Hi All, I would like to announce a, a flexible, low-cost ($35) data acquisition card for the Raspberry Pi. Our system brings an 8 channel, 200 ksps, 10 bit analog to digital converter to the platform. Notable hardware features include a programmable voltage reference, and user selectable AC or DC co...

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