I wanted to know if i could assemble the quinn board using a breakout board from sparkfun. I have downloaded the schematics from the wiki ( http://devwiki.electricimp.com/lib/exe/fetch.php?media=impee-quinn-sch-rev2.pdf ) but i wasn’t sure how to prossed.
You can put together a project that’s functionally just like the Quinn board - you’ll have to use through-hole versions of the components in the Quinn schematic unless you have the right equipment to put down surface-mount components.
Quinn’s operation is really simple - take all six pins on the imp and use them to output PWM signals. Run these PWM signals into the gate of an inexpensive FET, and use that to switch current through whatever device you please (in the case of the quinn demo, each channel controls one channel of an RGB LED light strip).
There’s an excellent functional demo on how to put this together from Adafruit, here: http://learn.adafruit.com/rgb-led-strips
A few points for successfully doing this with an imp (not an arduino as shown in the adafruit demo):
You can run the imp off the 12V supply you’ll use to power the LEDs. You’ll connect the positive side to the “P+” pad on your breakout board, and the negative side to “P-”
The positive side of the 12V supply is also connected to the “12V” line on your LED strips. We control them by sinking current through the LEDs. The LED cathodes are connected to the drains of your FETs, and when we turn the FETs on, current is allowed to flow out of the cathode, through the FET from drain to source, and off to ground.
You’ll need a through-hole version of the FET we used on Quinn (DMN2075U). Many FETs are perfectly fine for the job. Here’s one in a through-hole package that looks like it would do just fine for you: http://www.digikey.com/product-detail/en/IRLD120PBF/IRLD120PBF-ND/812490. There are a few things that it MUST have:
-> Vgs less than 3.3V (so that the imp can actually switch it on)
-> Vds 12V or greater (so that it doesn’t blow up when you hook it up to a 12V supply as you intend to
-> Decent power rating and heat dissipation - those LED strips need a lot of current, particularly if you’re using a long length of tape (around 600mA per channel per meter).
You don’t need the diodes shown on the drains of the FETs on the schematics if you’re just going to drive LEDs. Those are there to prevent inductive ringing from damaging the FETs if the board is used to drive an inductive load (like a motor).
Last but not least: there’s a couple of handy firmwares for quickly getting your project connected and working. Check out “quinn.default” for taking in an array of RGB hex values (so you can connect to the “disco” node) and “quinn.analog” for taking in a float between 0 and 1. https://github.com/tombrew/ei-fw-tom
Thanks for the help. I just got the imps from sparkfun.com.
I put together the “ControlBox: An internet-connected knob” as seen in the instuctables page but when i run the imp and get the code installed it only recognises the on/off pot switch… The value of the pot even when its on the “off” position it keeps changing. It stays below 0.09 at all times and when i move the pot around nothing changes…It keeps ignoring the pot signal and keeps changing tha value on its own! It doesn’t give me anything in the error log and restarting the impee / unplunging and then reinserting the imp didn’t have any effect. Looking forward to your answer while i’m assembling the quinn board.
Ok found it my old pot was broken
Hi, I am trying to control the Quinn device code from the browser (not the control knob box).
Is there any agent code to do this? Ie would the code use http.onrequest to send the rgb values?
Any pointers or example code would be much appriciated. Thanks David