I'm currently trying to make a wave generator using MCP4725, but after a few research online i found out that the frequency can only go up to 67Hz, however my project is to make a rehabilitation physiotherapy using eletricity. And i need my wave to be around 100Hz, can anyone recommend me any replacement or adding any method to increase the frequency. Also i'm kinda stuck at the part in simply make a wave generator, and i don't know what next to progress into, any idea ?
Not familiar with the MCP4725 but a quick look suggests it has a fairly fast response time. I would guess one limit my be how many steps are you using to create the wave? If you are using the full 12 bits I suggest you consider larger steps.
Can you explain how the 67Hz was derived?
Where is this?
Generating a wave is not an issue. You can use a wave table to generate values to send to PWM. Like this
However you will need to amplify the wave you generate - how will you do that?
AND
ENSURE PATIENT SAFETY. By using mains isolated equipmenyt - working it all from batteries is the best way to do that.
- How does an Arduino fit into this project ?
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do you require a single signal at 100KHz
sine wave, square wave, ???
have a look at Arduino AD9833 Signal Generator (DDS Function Generator)
EDIT: I missread the frequency it should be 100Hz
do you require a single signal at 100Hz
sine wave, square wave, ???
I would tend to use an ESP32 DAC, e.g. sawtooth wave output
have a look at simple-waveform-generator - it uses an Arduino DUE but concept would work on a ESP32
Hmmmm… you need to look at patient safety with this . I expect such a device has to be tested and approved by some organisation appropriate to your location.
This pretty well inhibits any home made devices .
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And what wave height do you need?
I was reading from this web https://electronoobs.com/eng_arduino_tut173.php . And find out i can make some kind of electric wave, but then again my teacher ask me to make wave at about 80Hz-100Hz since it is what TENS device produce, and i need to make it by arduino. I'm really new at arduino and electrical stufff, so i don't know what to do and where to begin with
recommend you get a Microcontroller with a builtin DAC (Digital to Analogue Converter)
this will save having interconnect host micro and DAC with resultant poor interconnections which can cause problems
I suggest the ESP32 which has two DACs, is low cost and is supported by the Arduino IDE
use lookup tables to generate different waveforms
EDIT: have a look at post simple-way-to-code-sine-frequency-decreases-while-amplitude-increases using a lookup table to generate sine waves
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i don't understand what do you mean by wave height ? If you're reffering to current then i'm aiming for below 10mA
If you already have the MCP4725 then use it.
Follow this tutorial on how to generate a 100Hz sinewave.
You can skip the section on calibration for now.
To me, a wave generator for physiotherapy means a pool of water with wave generation used to provide support and muscle strengthening for people with infirmities.
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TENS equipment for this purpose is plentifully available on the market. I don't recommend DIYing this and in the process foregoing thorough safety measures that manufacturers generally take in designing such equipment.
Waves have waveforms. Can you please post a picture or provide a description of what a single cycle of this wave you want to synthesize looks like?
a7
So this is a a school project? And all you need is to generate a 100Hz wave (presumably sinusoidal) with an arduino (would that be a Uno or can you use any arduino?)
Well, the tutorial you cited tells you what to do.
SO what more do you need?
I'm just learning to build model, not gonna test it on anyone
If you Google "TENS schematic" you'll find plenty of examples. You'll note that none of them rely on a DAC since a clean sinewave is not a necessity by any means. Pulsed high voltage (50 to 100V) DC is used. The pulses are generally pulse bursts with a high frequency in the kHz range and low frequency around 0.1Hz or lower. Current is generally limited to 20mA.
The output from a typical DAC (3.3V or 5V amplitude) will do exactly nothing on the human body, so it would need to be amplified in any case. But as pointed out above, a DAC is frivolous for this application.
Did the dfrobot code work?
i can't find that MCP4725 product in my country, mine is different from the site so i'm waiting for the shipment. But the site is very hepful for me, thanks a lot