PICAXE Projects: "MINI-VOLT"
Note: All pictures that follow are
"clickable". Clicking on them will show you an enlargement!
A lil' history ...
This project, called "Mini-Volt" (left circuit in picture) is a programmable LED Sequencer/Flasher and LiPo Battery Monitor that is based around the PICAXE 08M microcontroller. It is basically a spin-off of the Mini-Flash Programmable LED Flasher/Sequencer (shown on right in picture) which is based around the tiny 8-pin Picaxe 08M microcontroller. This neat controller is programmable in a BASIC-like language very similar to the "Basic Stamp" manufactured by Parallax Inc. This project also includes the ability to reprogram the LED sequencer using a PC-based (i.e. Windows) program that includes a unique and intuitive Graphical User Interface. In fact, the servo lead which is normally plugged into a spare channel for control, is also used to reprogram the Mini-Volt flasher/sequencer via a computer's serial port (9-pin) connection and programming cable. The free downloadable programming software also allows the user to "test" the LED sequence they develop by use of software-based graphical representations of the 3 LED channels. The sequence speed can also be programmed by the user. Each sequence contains 50 events and each of the 3 LED channels can be either ON or OFF for every events. If the user wants to develop a sequence with fewer events, this can also easily be programmed.
As if these are not enough features, the "Mini-Volt" also includes a control for each of the 3 channels that allows the user to use an R/C servo output (from a R/C receiver) as a "switch" control. This feature allows the user to control (active or inactive) each of the 3 channels in regards to the position of the servo control input. If the user uses a stick/slider as the servo input, the user will be able to define one of 16 "Zone" settings for each LED channel.
And lastly, the Mini-Volt includes a neat LiPo Battery monitor. Unlike the Mini-Flash, the Mini-Volt includes a 5 volt voltage regulator (7805) and is used to regulate the battery voltage (11.2v-18.5v) down to 5 volts which is used to power the Mini-Volt circuit. The Mini-Volt programming software also allows the user to program it for 3s, 4s and 5s battery packs. When the voltage of the battery drops below this preset cutoff voltage, the Mini-Volt will stop displaying the programmed LED sequence and will quickly flash (twice a second) all LEDS. The user can choose (via software) either Auto or Locked warning modes (Locked=when cutoff first reached, continually flash LEDs; Auto=Flash LEDs when battery voltage is < cutoff, display sequence when > cutoff). This programmable warning/flashing alarm allows for a visual indication that the battery is depleted to a point that you need to land/stop your model. If you were to drain the battery pack below it's cutoff point, you can and will probably ruin your LiPo pack.
Read more about
the Mini-Volt's operation by viewing the
Mini-Volt User's Manual ! (Rev 1) -
Mini-Volt Controller and Programming Cable (+ 16
mating LED connectors, Assembled)
and Programming Cable (+ 16 mating LED connectors, Kit/Parts)
Design Criteria Summary:
1) Design a simply and cheap programmable LED
flasher around 8-pin PIC
2) Design so LED sequencing speed and sequence pattern is programmable (3 LED channels)
3) Lightweight and simple to build (diy)
4) Provide an integrated LiPo Battery Monitor (visually indicate issues by quickly flashing all LEDs)
5) Use servo signal to vary how each LED channel responds (turn programmed pattern on or off)
6) Design programming software so it's intuitive and provide varying functions
7) Interface to computer using RS-232 (9-pin) connector most computer have... nothing special
8) Programmable almost indefinitely... change your sequence pattern/speed & warning voltage many times
9) Powers many LEDS (at least 400mA per channel... each typical LED uses 25-40mA)
10) Mini-Volt firmware is upgradeable (through DIYRC only... Free of charge, you just pay shipping).
Parts & Tools List ...
1) ...more coming soon
HERE TO SEE THE BUILDING INSTRUCTIONS FOR THE MINI-VOLT KIT !
PURCHASE A PREASSEMBLED & TESTED MINI-VOLT NOW!!
THE PICAXE FIRMWARE FOR THIS PROJECT IS NOT FOR SALE ....
Pre-programmed Picaxe chips are now available !
Click here to purchase one now!
DOWNLOAD THE MINI-VOLT PROGRAMMING
SOFTWARE !!! (Beta2)
* Click Here *
Screen shots of the Mini-Volt programming software (Rev1).... pretty slick !
(NOTE: PICS SHOWN BELOW ARE FOR THE MINIFLASH....
MINI-VOLT PICS WILL COME SOON!)
||File Menu Screen
|Loaded Program Screen
|| Sequence Testing Screen
| Download Screen #1
|| Download Screen #2
| Setup Menu (Comm port, Test speed, PIC
|| Help/About Screen
| Help/How-To Screen
|| Channel Menu #1 (click on tiny square
|Channel Menu #2
|| LED Color Menu (click on LED text)
| LED Servo Control Menu (select mask)
PROTOTYPE PICTURES !!
Testing and Operation Instructions...
I plan to add more information re: this neat gadget as time allows.
TWO OF THESE UNITS ARE BUILT AND ARE CURRENTLY BEING BETA TESTED !!!
**** VERY LIMITED QUANTITIES ARE AVAILABLE ****
Click Here to visit the
"PICAXE is a
trademark of Revolution Education Ltd (www.picaxe.co.uk)"