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The Right Circuit Turns Doppler Module Into A Sensor

Failed to load latest commit information. Feb 22, We thank your your support. This listing is for a CDM with its backpack, which contains all the necessary components. To make To make it work, you just need to apply 5V and you're good to go! You may find Arduino sample code on my webpage. Shipping will be done from Switzerland or Shenzhen depending on current stock and customer location. Another batch is in production and should be ready around August 15th.

Please have a look at the video below which shows what you should expect. For advanced technical specifications, please have a look at my webpage. Please also check that this Doppler sensor follows your country regulations.

It will however be able to measure much faster objects when they are close to the sensor. For more advanced details on what to expect you may read the dedicated paragraph on this webpage.

cdm324 doppler speed sensor

Don't hesitate to also read about my cheaper HB doppler module on tindie. Product: 3. Shipping: 3. Communication: 3. Mohd March 20, Rodrigo May 16, Prakasit March 29, Gary June 7, Lausanne, VD, Switzerland. We recognize our top users by making them a Tindarian. There isn't a selection process or form to fill out. Log In. More Info. View Options and Buy. Read More…. Specs and Docs Source Code Documentation.

Reviews 4 Review Breakdown 5. Average Ratings Product: 3.

cdm324 doppler speed sensor

Mohd March 20, Edit Delete reply.Function Features : 1. Noncontact detection,moving object detecting 2. Transmitting frequencyGHZ,can be widely applied in business,industries,word controlling etc 3. Provide various frequency range standards:-UK,-F. Independent transmitting and receiving route, can get the biggest gain,single channel operation 5.

High sensibility,high flexibility,low cost,operating distancem 6. Not influenced by temperature,humidity,noise,air flow,dust,ray etc,adaptive to terrible environment 7. Strong radio frequency interference resistance,stable performance,swift response,high sensibility 8.

Out put power is 5mW,does no harm to human bodies 9. Long distance detection rangem Small volume, easy to install Human beings or objects facing the sensor to move wil receive the best detection result Notice : 1. Don't operate during the power on in case of maloperation, wrong circuit or electric shock. Avoid installing the product in exposed place to prevent damage or affecting using longevity. Install the product far away from magnetic field in case of maloperation.

Install the product far away from moving conductors in case of maloperation. Parameter : 1. Operating Voltage: tpy Pulse Width: tpyUS 7. IF OutputMV 8. First we should say that ICStation doesn't accept any form of pay on delivery. Items used to be shipped after receiving the order info and payment.

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Note 1 Delivery Time of mixed orders with items in different Shipping Status should be calculated using the longest estimate times listed. STM32 Other. Prev: DC 5V 5. Add to Cart. Overview Buy More Save! Obstacle Avoidance Infrared SeTo content To menu To search. This is the reason why a fire truck's siren has a higher pitch when the truck is going towards you than when it is going away.

You may recall the article I wrote a couple of years ago about a nearly identical Doppler sensor, the HB While the HB is using a This has the main advantage of being compatible with European regulations ETSI and having good penetration in dry materials.

CDM324 24GHz Microwave Human Body Motion Sensor Module Radar Induction Switch Sensor

Moreover, as the main frequency is higher the patch antennas are smaller, hence the tiny 25x25x6mm module. This motion sensor can easily be purchased on eBay under the name CDM Oddly enough, looking for "cdm" on your favorite search engine won't bring any interesting results.

I therefore spent several hours tracing the origins of this tiny sensor. Finally, the advertised power consumption is identical to the HB's: up to 40mA 5V. The one you see above comes from InnoSenT.

cdm324 doppler speed sensor

From the formulas above, we can compute the circuit total gain and cutoff frequencies. I'll spare you the maths, the suggested amplification is 60dB and a band pass filter from 3. However, this isn't exactly true as the filter cutoff slope isn't vertical. Here's the simulated amplification output generated using LTspice: You may therefore be able to measure much higher speeds if the moving object is close to the sensor.

This is the very low resolution recommended amplification circuit that you will find online. Simulating it leads to raising eyebrows: Many many things are odd with this recommended amplification circuit: - No high pass filter on the second amplifier remember, the cutoff slope in the first amplifier stage isn't vertical - I don't see any reason for that 1nF capacitor when the high pass filter is done using the first op-amp - Amplification on the first stage is while the amplification on the second stage is - Which leads to a total gain of 94dB The last point is crucial.

Given the first amplification stage has a gain ofthis means there's only 1. As the cutoff slope isn't vertical, this means that the LM isn't the right op-amp for the job! For example, at 10kHz the amplification iswhich is a GBW product of After lots of experimentation and performance comparisons with my previous HB module, you can see above the final amplification circuit I chose.

Using a comparator is a simple way to 'extract' the amplified output main frequency but I'm quite sure running an FFT on that signal would be quite interesting!As it turns out, you can.

But can you make it output useful information? Frequency output is proportional to the velocity of the detected object; the maximum speed for the sensor is only Still, if your tastes run more toward using this module on the 1.

Hey there! I should also mention that by changing a few resistors higher speeds can be measured, but may result in more noise being picked up. Any indication of the sort of range it will detect a human at? I bought your HB module and would be interested in this if it can improve on the m range I got with that.

What would it take to modify the circuit to read velocity of a lead object size 4mm betweenfps at distances of cm? Therefore I would have thought with a gain of Hello Dave, I think you are indeed right.

The high GBW is just an added bonus. Shame that no modules can be purchased, that measure distance instead of speed. HW is almost the same except and added sawtooth generator that feeds the freq.

You can buy those, they just cost a lot more. So the frequency is fixed. I want to measure liquid levels in large metal fuel tanks and I wondered if this sensor could be used to measure RF absorption and calculate from there.

What I really want is a module with scanning radar decent resolution and great boresight ranging, doppler would be cool too, much prefer phased array but mechanical scanning is enough.

This looks like it could possibly be the start of this, maybe at least for a slow moving vehicle or drone. I played with those as well. You can also get the respiration and heart rate of a person, provided it is aimed at the chest and the person is rather still. I wonder if you could do it with the newer ones which are using the BISS ic which are simpler and cheaper.

Hello, do you happen to have any more information on how to use this radar to get the heart rate and respiration data? Would it be possible in this case to disable the module TX section and use the RX only as a carrier detector? I made thus and got decent results with CDM Can you tell me what sensor should i use to measure ball speed. CDM cannot detect a Tennis ball. This site uses Akismet to reduce spam.

Learn how your comment data is processed. By using our website and services, you expressly agree to the placement of our performance, functionality and advertising cookies. Learn more. Report comment. So, this article is misleading correction of misleading information. Very meta. You could add a varactor in there to make it tunable. Do you know of a sensor that might be suitable. Any idea if there is a similar sensor that is able to go…faster?It is constantly transmitting and receiving at 24GHz.

Besides that, there are some other peripheral components. The PCB connects to the module with 3pin header. The output of the CDM module has very low level mV peak to peak at best so it has to be amplified. For that I used the OP amp circuit found in this post. The output signal after the amplifier is somewhere at 3. At first, I tried using an analog comparator to convert analog signal sine wave to digital pulses.

When the input signal was lower than 3. The real chalange came when I tried to sample those pulses. The problem was that I was trying to analyse the frequency in time domain with many reflected signals interfering with each other. I also connected the output of the amplifier to a ADC input of the microcontroller. This means that FFT time to frequency domain transformation can be calculated accurately and in timely fashion.

Arduino HB100 radar

With some testing 20kHz sample rate and FFT size was determined to be enough. User can also zoom in and out on the graph using the joystick. Speed reading is displayed with big font and updates only about 3 times per second to get readouts easily.

The graph however, is fluid and updated with 25Hz. To power down the user has to hold the joystick down for about 1 second. Pushing the joystick down briefly during normal operation enters the menu where user can adjust some parameters. The battery lasts for about 2 hours of operation.

Schematics can be found here. The hosing consist of three parts. The front wooden part, the back aluminum part and they joystick button which I machined with my CNC. All of those parts can be 3d printed as well. The button is glued on the joystick.

The back and front part are screwed together with 4 kniping screws. The radar can measure speed of an average human at range up to 5m and a car with range up to 20m.

cdm324 doppler speed sensor

The bigger the target the stronger the reflection. The antenna would have to be at least twice the size. Render of the device.You may recall the article I wrote a couple of years ago about a nearly identical Doppler sensor, the HB While the HB is using a This has the main advantage of being compatible with European regulations ETSI and having good penetration in dry materials. Moreover, as the main frequency is higher the patch antennas are smaller, hence the tiny 25x25x6mm module.

This motion sensor can easily be purchased on eBay under the name CDM I therefore spent several hours tracing the origins of this tiny sensor. The one you see above comes from InnoSenT. It consists in 2 cascaded inverting band pass filter circuits:. From the formulas above, we can compute the circuit total gain and cutoff frequencies. The InnoSenT application note allows us to put these frequencies in context:.

Submit Comment. Spamcheck Enabled. Theremin is an early electronic musical instrument controlled without physical contact by the thereminist performer. It is named after the No Ratings Yet. Leave a Comment Click here to cancel reply. Read previous post: Optical Theremin Musical Instrument Using Arduino Uno Board Theremin is an early electronic musical instrument controlled without physical contact by the thereminist performer.