Progression of a PICAXE LED Chaser (Knight Rider) LED Display

There was a question on the PICAXE forum asking about building up a "Knight Rider" display.  The '80s TV show "Knight Rider" featured a 1982 Pontiac Trans Am named "KITT" that had some blinky lights mounted in the hood that somehow let the car solves crimes and do some other amazing stuff.  Pretty impressive technology for an early '80s American car!

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The authentic way to do the "KITT" display is to show LEDs moving back and forth by turning a "main" LED on full bright and surround that full bright LED with progressively dimmer LEDs.  That is not that hard to do using the PWM (Pulse Width Modulation) features of the PICAXE, but I thought there may be an easier way.

I wanted to test a simpler way to simulate the display on "KITT" by just turning the LEDs on/off in sequence quickly.  I was also interested in experimenting with the PICAXE "let dir", "let pins", and "lookup" and this seemed like an easy platform to do this.  In the first attempt a PICAXE 18M2 was used to simulate an eight LED "KITT" display.  The result was surprisingly excellent.  To me, the PWM is not really needed due to the persistence for your vision and the LEDs.  An ADC input on the PICAXE was used to allow for an adjustable delay on how fast the display moves.  Here is a short video of the results:

The original forum question was asked by Jacob2803.  He gave it a try with my code as well and here is a short youtube video of his nice result:  http://www.youtube.com/watch?v=HwoHKqRI-sY
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After seeing an eight LED Chaser display the discussion of using more LEDs came up.  More is always better, right?.  The PICAXE forum is an interesting place.  It has participation of users from all levels; beginner to expert, and the brainstorming of solutions (on many problems) can be inspiring.  Many options were provided on increasing the LED count.  My thought on increasing the count on the LED Chaser display was to use the PICAXE 08M2 and the 74154 (4:16 Decoder).  The PICAXE 08M2 has fewer outputs than the 18M2 that was used above, but the 74154 only needs four control signals to turn on any one of 16 LEDs at a time.

Here is a picture and short video of what the 16 LED Chaser looked like on the development board:

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The 16 LED Chaser looked so cool, I decided to move it to a PCB and keep it "forever".  It barely looks like it has any similarity to the development board build.  Since the circuit is very minimal it cleans up well on the PCB.

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I programmed a few different chaser patterns into the PICAXE that can be selected with a button press.  Here is a short video of the PCB version of the 16 LED Chaser in action.

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My code and schematic is below in case you want to build your own.  If you build it and mount it to a 1982 Pontiac Trans Am please send us a pic.  ;)

Schematic:

PICAXE Code:

#rem
 *******************************
 ***** www.WhiskyTangHotel.Com  *****
 *******************************
    Project Name: 16 LED Chaser with 08M2 and 74590 Decoder

    Start Date: May 18, 2012

 *******************************
    PICAXE PE Rev: MacAXEPad 1.3.2
 
#endrem

#picaxe08m2
let dirsC = %11110111
'b0 is used as a general loop counter
Symbol StepDelay = b1
Symbol WhatCase = b2
Symbol MaxCases = b3 'Init value set below.  The # of possible display cases select routines programmed
'w2 (b4 and b5) used in random LED Case Select
Symbol ButtonPush = pinC.3

'Initialize some values
StepDelay = 20  ' Time to keep the only sigle LED the 74590 can turn on until moving to the next LED

Whatcase = 4    'Case Select routine that 'kicks things off' after reset
MaxCases = 4    '# of possible display cases select routines programmed.

main:
if ButtonPush = 1 then 'jump to a different Case Select routine
pause 25
Do While ButtonPush = 1
pause 25
loop
pause 25

if WhatCase = MaxCases then
let WhatCase = 0 ' reset WhatCase if it is equal the # of possible display cases programmed
endif
WhatCase = WhatCase + 1
endif

Select Case WhatCase

Case 1  'LEDs scan up and repeat
gosub LEDsUp

Case 2   'LEDs scan down and repeat
gosub LEDsDown

Case 3 'LEDs scan up the down and repeat.  This simulates the display on the "KITT" car in KnightRider
gosub LEDsUp
gosub LEDsDown

Case 4  'randomly turn on one LED at a time
gosub LEDRandom

end select

goto main

'LED pattern subroutines here.  Of course, more case routines can be added.
LEDsDown:
for b0 = 0 to 7
let pinsC = b0
pause StepDelay
next b0
'jump to 16 to turn on bit position 5
for b0 = 16 to 23
let pinsC = b0
pause StepDelay
next b0
return 'LEDsDown

LEDsUp:
for b0 = 23 to 16 step -1
let pinsC = b0
pause StepDelay
next b0

for b0 = 7 to 0 step -1
let pinsC = b0
pause StepDelay
next b0
return 'LEDsUp

LEDRandom:
RANDOM w2
let pinsC = w2 // 23 + 1 '"//" is modulus divide (returns remainder)
return 'LEDRandom

'===================================================

Voltmeter Clock w/ F°, C°, and K° temperature readout.

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The objective was to create a real time clock using three analog voltmeters controlled via Pulse Width Modulation (PWM) to display "hours", "minutes", and "seconds".  At the press of a button the three meters display temperature in degrees F, C, and K.

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Here is a short (time lapse) video of the rig in action:

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There are four major components to the build.

• PICAXE 14M2 microcontroller

• DS1307 Real Time Clock (RTC) module

• DS18B20 Temperature Sensor

• Three 0-2VDC analog voltmeters (refaced to display as "hours", "minutes", and "seconds")

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The meters were taken apart to install custom faces.  A free program called "MeterBasic" was used to create the custom faces for the three voltmeters (see pic below).  Note that the meters have labeling to display temperature in degrees F, C, and K.

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See the black button below the "seconds" meter?  Pressing this button causes the meters to display their respective temperature.  

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Here are a few shots of the build process.  The "red thing with the black tip" is the DS18B20 temperature sensor.  In front of the meter in the middle (what will be the minutes meter), you can see a small PCB with two buttons.  These are used to set the time on the DS1307 Real Time Clock.  Pressing both buttons will set the seconds to zero.

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The digital outputs on the PICAXE 14M2 put out about 5VDC maximum.  Our analog voltmeters only go to 2VDC maximum.  We set up a voltage divider circuit and a trimpot to allow the output from the PICAXE 14M2 to read full on our 2VDC meter.  The 100K trimpot (the little blue things in the pic below) allow for precise adjustment of the full scale reading.  Pushing the hour set, minute set, and read temperature button at the same time will force all meters to full scale.  This is to provide for precise tuning of the trimpots to calibrate the full scale reading of each meter.

After we have calibrated the meters to read "0" with no voltage and "full scale" from a high digital output on the PICAXE 14M2 we still have to be able to control the meters to display the time.  This is done by reading the time on DC1307 RTC via the I2C bus and the PICAXE 14M2.  Pulse Width Modulation control is used to convert the time (hours, minutes, and seconds) into a corresponding "average" voltage.  That PWM signal drives the three meters to display time.  The PICAXE 14M2 has four PWM output drivers that are well up to the job for this.

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Here is another look at the time set buttons.  They are located on the bottom side of the clock enclosure.

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The rig is powered by a rescued wall wart from an old Sony CD player.  The wall wart puts out 9VDC which is tamed to 5VDC with a LM7805 voltage regulator.

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If you want to build your own, the schematic looks like this.  I will send my (sloppy) source code on request.

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Another pic of the finished rig.

Binder Clip as Button Cell Holder

The magnificent office binder clip in action:

Simple LED Light from Spare Parts

A piece of flat aluminum stock, an old heat sink, a switch, and two cheap automotive tail light LEDs. Put them together and get this:

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Suzuki V-Strom (DL1000) Gear Position Indicator Project

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UPDATE April 15, 2012:  Thanks go out to the over two dozen brave DIY'er that have successfully built and installed the rig proving that the instructions are complete and design is solid.  If your rig is not working double triple check your wiring.  Send me an email and I will try to offer guidance if I can.

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The objective was to provide a low cost gear position and ambient air temperature display for my 2009 Suzuki V-Strom (DL1000). Also, to open source the project design with documentation so that anyone with basic electronic skills can duplicate the design for their motorcycle.

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Theory of Operation:

Most modern motorcycles have a Gear Position Indicator (GPI) signal wire from/to the Engine Control Module (ECM) that outputs a voltage reading of 0 to 5VDC depending on which gear is selected. This project uses a PICAXE 18M2 microcontroller to measure the voltage on that GPI signal wire, process that measurement, and display the selected gear on a 7 segment LED display. At the press of a button, the PICAXE 18M2 reads the ambient air temperature (as measured from a DS18B20 temperature sensor) and displays the reading in Celsius or Fahrenheit on the 7 segment LED display.

A few comments before you do anything....

This is a DIY project. I guarantee nothing other than the project works on my 2009 Suzuki DL1000 and that I will not rip you off if you decide to buy the software customized PICAXE18M2 from me. If you have done DIY electronic projects you understand that wiring errors, etc. happen and have to be debugged. If you haven't done an electronics DIY project, this build is not that difficult and you should be successful but expect delays as you check your work, decided where you what to mount the components, route wires, etc. Check your work often during your build. Even the very experienced make wiring errors and create solder shorts (among other things). Basically, you are taking on some risk. I will provide informal advise when I can, but offer no promises of any support expectation level. Please understand I treat this only as a hobby.

With the exception of the PICAXE 18M2 microcontroller, all the components are readily available and cheap. If you have done a few electronics projects you likely have many of the parts already your 'spares' kit. The PICAXE 18M2 microcontroller needs to be loaded with some customized software I wrote to make the project work. I can install this software and ship the programmed PICAXE 18M2 directly to you if you like.

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A few answers to common questions:

- Why do I have to get the PICAXE 18M2 from you? Can't I program my own?

- You can write the software and program your own PICAXE if you have a development board. Goto www.picaxe.com to learn more.

- Will it work on my motorcycle?

- Currently the design has been tested on the:

2009 Suzuki DL1000
   2010 Suzuki DL650
           Suzuki Bandit

It should work if you have a late model bike with a Gear Position Indicator (GPI) signal wire. The GPI signal wire puts out a voltage (between 0-5VDC) for each specific gear. The software for the PICAXE 18M2 will likely need minor adjustments for motorcycles not yet tested. I can quickly make these adjustments if you tell me the voltage readings of the GPI wire for each gear (and neutral) of the target motorcycle.

- What's is the most difficult part of duplicating the project?

Avoiding wiring and solder mistakes. Also, after you get the project wired and soldered up, deciding what to mount it in and where to place it on the motorcycle.

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Bill of Materials (the PICAXE 18M2 = $8 + any donation amount via PayPal):

Before we get into the general bill of materials list, let's talk about getting the PICAXE 18M2:

- the PICAXE 18M2 microcontroller is the "brain" of the project.

- the PICAXE 18M2 can be purchased on the internet for about $5.00; however...

- it must have my software downloaded into the PICAXE for the project to work

- I will mail the programed PICAXE 18M2 to you (lower 48 USA only)

- Just PayPal $8.00 USD plus any [very welcome] donation amount you would like to add to:

- BE SURE to tell me if you want the temperature displayed in degrees C or F.

- BE SURE to provide a shipping address.

- BE SURE to provide the make/model info on the target motorcycle for the project.

- If you are designing to a motorcycle not listed above, give me the GPI signal wire voltages for each gear and neutral.

- At that price it should be obvious that the project was not done to make money, I happily accept any donation above the $8.00 amount. I have provided donor hardware/software for well over two decades and like the model. Some donate nothing over the requested amount; others donate a lot. The choice is totally yours...

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"All the Other Stuff" Bill of Materials (~$15):

Listed below is The Bill of Materials (B.O.M) for the other components. You can find these components in many places. I like Mouser.Com because their prices are good, they are fast, they have good shipping rates, and they will let you order in single qualities. I have included Mouser.Com part numbers for each item that were valid at the time of this writing.

QTY - Description

1 - DIP socket (18 pin) for the PICAXE 18M2

- allows easy removal of the PICAXE 18M2 in the event of a re-program.

- allows you not to solder directly to the PICAXE 18M2 if this concerns you.

- allows you to start the project without the PICAXE 18M2 in hand

- One of many examples is PN#4818-3000-CP from Mouser.Com ($0.20)

1 - Seven segment display with decimal point. Must be Common Anode!!!

- Forward Voltage spec = 1.8-2V

- One of many examples is PN#LDS-HTA514RI from Mouser.Com ($1.09)
 - ALWAYS a good idea to confirm the pin out.  MUST be done if you don't order LDS-HTA514RI.

1 - 5 Volt DC Regulator

- PN#926-LM2940T-5.0/NOPB from Mouser.Com ($1.68)

- LM7805 could also work if you already have one handy

1 - .47uF capacitor for voltage regulator input on the LM2940T-5.0

- any current rating or tolerance is fine

- One of many examples is PN#UFW2AR47MDD from Mouser.Com ($0.08)

1 - 22uF capacitor for voltage regulator output in the LM2940T-5.0

- any current rating or tolerance is fine

- One of many examples is PN#REA220M1CBK-511P from Mouser.Com ($0.06)

1 - Temperature Sensor (optional, but does not make the project more difficult)

- PN#700DS18B20+ from Mouser.Com ($4.77)

1 - Push button switch (optional for temperature, but does not make the project more difficult)

- any current or voltage rating is fine

- One of many examples is PN#104-0013-EVX from Mouser.Com ($0.91)

1 - 4.7K resistor for DS18B20 temperature sensor (optional for temperature)

- any current rating or tolerance is fine

- One of many examples is PN#299-4.7K-RC from Mouser.Com ($0.10 each)

8 - 330R current limiting resistors for the seven segment display

- any current rating or tolerance is fine

- One of many examples is PN#299-330-RC from Mouser.Com ($0.10 each)

2 - 10K pull down resistor for temperature button switch and PICAXE (not optional)

- any current rating or tolerance is fine

- One of many examples is PN#299-10K-RC from Mouser.Com ($0.10 each)

2 - 22K pull down resistor for PICAXE

- any current rating or tolerance is fine

- One of many examples is PN#299-22K-RC from Mouser.Com ($0.10 each)

1 - PCB "perf" board to attach the parts to

- Many examples are available. Select one that aligns the design of your final packaging

- One of many examples is PN#854-SB300 from Mouser.Com ($3.99)

- some 22 gauge solid core hook up wire, solder, mounting 'box', electronics DIY know how...

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After you get your parts, connect them as shown in the schematic below. You may not (or may) want to mimic by component placement as shown in the picture above. A common thought may be to use longer wires to connect the 7 Segment Display to the PICAXE 18M2. That is fine and may give a cleaner look because the 7 Segment Display could be remoted and would be the only thing visible to the rider; the other circuity could be hidden. I'm sure there are many other packaging considerations.

Check your work often with an ohm meter to verify your connections and that there are no accidental shorts created in the solder process. It is a lot harder to debug an error if you wait until the end; sometimes seemingly impossible...

(click the schematic to make it larger)

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Now that you have the components installed and soldered down it is time to connect the unit to the bike. But first, be patient... Let's check a few things:

- Apply 12VDC power the the unit. Take note of + and GND; don't hook it up backwards!!! The unit should go through a "Count Up/Count Down" Self Test followed by displaying the temperature (in C or F; whichever you asked for).

- Then the unit will try to display the current gear. Since the unit is not connected to the bike this number will not mean anything. The number may jump around some as well. That's normal right now.

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Now... To the bike:

On the 2009 Suzuki DL1000 you are looking for a PINK wire on the ECM; that is the GPI signal wire. I simply unplugged the ECM connector located behind my battery to find it. This is the GPI signal wire and may not be PINK on other motorcycles. See pic below:

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We want to connect leg 18 on the PICAXE 18M2 to this PINK wire. Many ways to do this, but in the pic below you can see I removed a small piece of insulation, wrapped the wire from leg 18 on the PICAXE 18M2 around it. I then soldered it on for a solid, reliable connection.

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Congratulations. After connecting those three wires (12VDC, Ground, GPI signal wire) to your motorcycle you will now have a working digital gear position indicator with temperature readout and you will have the bragging rights of building your own 'farkle'. Mount it in a handy place and send us a picture of your final product.

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A few more visuals:

Video of finished product connected to the bike:

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Video of the prototype functioning on the bike:

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Video of the prototype functioning "on the bench":

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www.whiskeytangohotel.com

H-Bridge Motor Driver Tutorial w/ OWI Edge Robot Arm and PICAXE 20M2

Complete wiring diagrams, parts list, and PICAXE source code provided below.

Even in its "natural" state the OWI Edge Robot Arm is a pretty interesting toy. It comes with DC motors and a cable switch box that allows you to manually control 1) Grip, 2)Wrist, 3) Elbow, 4) Shoulder, and 5) Base. Prices for the unit are typically less than $40.

The greatest thing about the OWI Edge Robot Arm is that you assembly it yourself so you understand it well and it is easy to customize.

Intrigued by the idea having a robot that I could personally program to do my evil bidding was overwhelming. Just imagine the possibilities..... Also, I am lucky enough to have a sister that was willing to give an adult a child's toy as a Christmas gift.

The Objective: Replace the wired control box with a programmable microcontroller to let the OWI Edge Robot Arm run autonomously.

In the end, the project results were in some ways underwhelming. Due to the lack of position feedback and the "slack" in the gear/joint movement mechanics it is impossible to control the robot with any precision. In other words, if you move an axis one direction for 1.5 seconds it does not mean it will be in the original starting position if you simple reverse the movement for 1.5 seconds.

That said, having a controllable robot is still pretty cool and it does make a excellent platform to to demonstrate motor drive and control capability with a microcontroller.

Let's go through the build....

The following hardware was chosen because it is cheap, easy to use, and readily available:

1. OWI Edge Robot Arm (it that is not obvious then stop reading now)
2. Three SN754410NE motor driver ICs to supply the drive current to the DC motors.
3. One PICAXE 20M2 to control which direction to spin the motors.
4. A "strong" 5VDC power source.

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Let's take a look at the SN754410NE motor driver IC. First, why is it even required? Motors draw a lot of current. The motors on the OWI Robot measured up to 800mA at full load. That's way too much current to expect from a microcontroller output to drive, so the SN754410NE is required to supply that current. The outputs of the PICAXE 20M2 are programmed to "tell" the SN754410NE motor driver what direction to spin the robot's motors.

Understanding the SN754410NE is simple and straight forward in the configuration we want to use it in. Take a look at the SN754410NE pinout diagram:

One SN74410NE motor driver can control two DC motors to spin in any direction you like; clockwise or counter clockwise. Sure, there are 16 legs on this SN74410NE motor driver chip to wire, but not to worry. If you break it down it is simple. The designers were clever and grouped all the legs for one motor on one side and the legs for other motor on the opposite side. And really, for this application all but four wires on each side are connected to power (+5VDC) or ground. So really, you are only concerned about connecting four "special" connections per motor used. Two will go to the motor and two will go to the PICAXE 20M2 microcontroller.

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So connecting one motor to the "lower" legs of the SN74410NE motor driver IC will look like this:

See; it's easy. Most legs of the SN74410NE motor driver are connected to +5VDC and ground.

To +5VDC: Legs 1, 16. Legs 8, 9

To GND: Legs 4,5. Legs 12, 13

As for the four "special" connections mentioned above:

Legs 3 and 6 connect to the motor.

Legs 2 and 7 will go the the PICAXE 20M2 microcontroller (more on that later).

Let's point out how the SN74410NE motor driver works:

Condition of Leg 3 Condition of Leg 6 What does the motor do?

------------------ ------------------ -------------------------

0 Volts 0 Volts Motor does not spin

0 Volts 5 Volts Motor spins Clockwise

5 Volts 0 Volts Motor spins Counter Clockwise

5 Volts 5 Volts Motor does not spin

Basically what the table is trying to show is that if Leg 3 and Leg 6 have different voltages the motor will spin. If Leg 3 and Leg 6 have the same voltage the motor will stop. You can "test" this before you connect the PICAXE microcontroller if you like by just connecting the legs straight to the supply voltage and ground. Later, the PICAXE 20M2 will be programmed and connected to control the motor (stay tuned).

But wait, the OWI Edge Robot Arm has five motors and the SN74410NE motor driver can only control two motors. That's no problem if three SN74410NE are used.

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Below is what the three SN74410NE motor driver ICs look like on a breadboard after the power and grounds are connected. Six motors can be controlled with this set up. Only five motors are needed so we will not connect a motor to the upper side of the right most SN74410NE motor driver.

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Let's move from discussing the SN754410NE motor driver IC and switch to controlling how the motors spin control with a custom programmed PICAXE 20M2 microcontroller.

The PICAXE 20M2 is a low cost microcontroller (less than $4) that is easy to program for this application. To control five motors we need 10 outputs; two outputs for each of the five motors. The PICAXE 20M2 has 18 outputs and that is plenty.

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Notice how the PICAXE 20M2 legs are labeled; b.7, b.6, etc. The drawing below shows how to wire up the whole system. It shows where to wire power and ground. It shows where wire the motors. It shows where to wire in the PIXACE 20M2 so it will work with the program source code below.

Again, notice nothing is connected to " upper" portion of the SN754410NE motor driver on the far right. Good engineering practice would say the inputs (Leg 10 and Leg 15) should be tied to ground. But, we aren't designing for a Mars rover or anything critical, so everything should be fine. As a general rule leaving inputs floating can lead to a risky design.

The PICAXE 20M2 is programmed (again, example source code below) to control the direction of each motor. From above we know that varying the condition of the SN754410NE motor driver IC inputs has a resulting spin on the motor. The source code for the PICAXE 20M2 simply forces the two SN754410NE motor driver IC inputs high and/or low to make the robot motor spin in the desired direction. High/Low will spin the motor one way. Low/High will spin the motor the other way. The PICAXE 20M2 output conditions are held static in the source code with the PAUSE command to determine how long the motor will spin. If the PICAXE 20M2 is programmed to output High/High or Low/Low the motor will stop moving.

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Let's wrap this up. These wires connect to the five motors on the OWI robot:

These are the wires that go to straight to the SN754410NE motor driver ICs. If you connect these wires straight to Power and Ground you can document which connector wires control what motor and in what direction.

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After you wire the PICAXE 20M2 to the SN754410NE motor driver ICs your breadboard will look something like this:

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Add in the wires from OWI Robot motors and your done with the hardware. It will look like this:

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Picture of the final build with everything wired in:

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A short video demo of all five motors being controlled on the OWI Robot. Be aware that the motors can pull over 500mA each. Running several motors at once can demand a lot of current, so if your design doesn't work suspect the power supply may not have enough output current.

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A below is source code for the PICAXE 20M2 to make it all work. Basically, the PICAXE 20M2 outputs are set HIGH and/or LOW to control the motors. A PAUSE statement determines how long that motor should stay on. Both outputs LOW stop the motor movement. It is possible to move more than one motor at a time if you have a 5VDC power source that can supply enough current. In the example below all motors are excerised one at a time. The code can be modified to make the OWI Robot dance to your wishes:

; *************************************

; ***** www.whiskeytangohotel.com *****

; *************************************

; Project Name: OWI Robot Arm "Nancy"

;

; Start Date: DEC 2011

;

; Program Rev History:

;

;

; *******************************

; PICAXE PE Rev: MacAXEPad 1.3.2

;

#picaxe20m2

'Define the outputs to be discriptive

symbol Grip_Close = b.0

symbol Grip_Open = b.1

symbol Wrist_Up = b.2

symbol Wrist_Down = b.3

symbol Elbow_Up = b.4

symbol Elbow_Down = b.5

symbol Shoulder_Out = b.6

symbol Shoulder_In = b.7

symbol Base_CCW = c.0

symbol Base_CW = c.1

'Subroutine move commands are:

' GripOPEN GripCLOSE GripSTOP

' WristUP WristDOWN WristSTOP

' ElbowUP ElbowDOWN ElbowSTOP

' ShoulderIN ShoulderOUT ShoulderSTOP

' BaseCCW BaseCW BaseSTOP

' StopAll

' (motion referenced from behind the robot

main:

gosub WristDOWN

gosub StopALL

pause 1000

gosub WristUP

gosub WristUP

gosub StopALL

pause 1000

gosub ElbowDown

gosub StopALL

pause 1000

gosub ElbowUP

gosub StopALL

pause 1000

gosub GripOPEN

gosub GripCLOSE

pause 1000

gosub GripOPEN

gosub GripCLOSE

gosub StopALL

pause 1000

gosub ShoulderIN

gosub StopALL

pause 1000

gosub GripOPEN

gosub GripCLOSE

pause 1000

gosub GripOPEN

gosub GripCLOSE

gosub StopALL

pause 1000

gosub ShoulderOUT

gosub StopALL

pause 1000

gosub BaseCCW

gosub StopALL

pause 1000

gosub BaseCW

gosub BaseCW

gosub StopALL

pause 1000

gosub BaseCCW

gosub StopALL

pause 1000

gosub GripOPEN

gosub GripCLOSE

pause 1000

gosub GripOPEN

gosub GripCLOSE

gosub StopALL

pause 1000

gosub WristDown

gosub StopALL

goto main

' ------GRIP------

GripOPEN:

high Grip_Open

low Grip_Close

pause 1000

return 'GripOpen

GripCLOSE:

low Grip_Open

high Grip_Close

pause 1000

return 'GripClose

GripSTOP:

low Grip_Open

low Grip_Close

return 'GripStop

'-----------------

'------WRIST------

WristUP:

high Wrist_Up

low Wrist_Down

pause 1800

return 'WristUp

WristDOWN:

low Wrist_Up

high Wrist_Down

pause 1800

return 'WristDown

WristSTOP:

low Wrist_Up

low Wrist_Down

return 'WristStop

'------------------

'------ELBOW------

ElbowUP:

high Elbow_Up

low Elbow_Down

pause 3000

return 'ElbowUp

ElbowDOWN:

low Elbow_Up

high Elbow_Down

pause 3000

return 'ElbowDown

ElbowSTOP:

low Elbow_Up

low Elbow_Down

return 'ElbowStop

'------------------

'------SHOULDER------

ShoulderIN:

high Shoulder_Out

low Shoulder_In

pause 2500

return 'ShoulderUp

ShoulderOUT:

low Shoulder_Out

high Shoulder_In

pause 2500

return 'ShoulderDown

ShoulderSTOP:

low Shoulder_Out

low Shoulder_In

return 'ShoulderStop

'------------------

'------BASE------

BaseCCW:

high Base_CCW

low Base_CW

pause 3000

return 'BaseCCW

BaseCW:

low Base_CCW

high Base_CW

pause 3000

return 'BaseCW

BaseSTOP:

low Base_CCW

low Base_CW

return 'BaseStop

'------------------

'----StopAll-------

StopAll:

gosub GripStop

gosub WristStop

gosub ElbowStop

gosub ShoulderStop

gosub BaseStop

return 'StopAll

'----------------

www.whiskeytangohotel.com/

"Echo Box" using PICAXE 08M (Complete)

What is an "Echo Box" you ask? Simple. You tap on the box and a few seconds later the box echos those taps back to you. The video below shows the rigs operation. Keep reading if you want the build details.

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I have programmed a PICAXE 08M microcontroller to monitor for current on a piezo disk. The piezo disk outputs a current when it is struck (or tapped). The PICAXE sample and holds the cadence of the taps with software. If there are no taps for about a second or so the program assumes the tapping is complete and echos the taps back to you on the box.

The piezo sets inside a tube of PVC pipe between two pieces of wine cork that are cut to barely touch the roof of the box. This does a great job of transferring the taps from the top of the box to the piezo input. Here is a picture of the piezo disk resting on top of a wine cork.

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And here is the piezo input disk in its final configuration with another piece of wine cork placed on top of it. Basically creating a "piezo sandwich" with wine cork.

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Below is how the input from the piezo traces out on the 'scope. A diode in parallel with the piezo protects the PICAXE from getting hit with a negative voltage spike. A 1M resistor also helps to tame the input and make it more predictable.

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A DC motor with an offset counter weight spins to shake the box and provide the feedback for the echo.

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The circuit perf board is shown below. The red LED is simple there to provide a visual clue that the piezo tap was processed by the PICAXE. It is used only for debug of the project and could be removed. You can also see two 470uF capacitors on the board. Take note that the motor will not get enough instantaneous energy to start without these capacitors. One final note, a transistor as heavy as the 2N6284 is not required, but I had one handy. The more common 2N2222 should be fine.

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The rig is powered with 5VDC provided by a rescued Blackberry charger. The headphone jack is not for audio; this jack is used to download the control program into the PICAXE 08M. This jack allows you to easily change the personality of the Echo Box.

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The completed Echo Box:

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For those that have hung in there so far with the details, the circuit schematic and code is shown below:

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; *******************************

; ***** www.IronJungle.Com *****

; *******************************

; Project Name: Echo Echo

; [with thanks to AndyGadget & the PICAXE Forum]

;

; Start Date: November 15, 2011

; Completed: December 4, 2011

;

; *******************************

#picaxe 08m2

#com 11

' Assign names to pins, variables to registers,and constants.

symbol rnd = w6 'Word variable : Current random number

symbol kdel = w5 'Word variable : Delay between last and current knock input

symbol cnt1 = b0

symbol kcnt = b1 'Number of knocks

symbol pptr = b2 'Pointer to knock delay storage array

symbol tmp1 = b6 'Reusable variable

symbol tmp2 = b7 'Reusable variable

symbol mic = pin2 'Microphone input (can also be output)

symbol knock = 4 'Knock motor output

symbol led = 0 'Indicator LED for testing

symbol pstart = $50 'Start of storage area

symbol tmax = 800 'Time-out value for delay - About 1.5 seconds

symbol settle = 80 'Settling time for microphone

'This section is where the person knocks.

'The time between successive knocks is stored

' until there is a pause of 1.5 seconds or so.

do 'Start of main loop

kcnt = 0 'Initialise knock counter

input 2 'Define mic as input to detect knocks

do

for kdel = 1 to tmax 'KDel is counting loops to determine time between knocks

if mic = 1 then 'Detect HI on microphone input

inc kcnt 'Add 1 to number of knocks

high led 'Flash LED to help debugging

pause settle 'Wait for oscillations to stop

low led

kdel = kdel + settle 'Add settle time to loop counter for accuracy

pptr = kcnt * 2 + pstart'KCnnt is a word variable so need to add 2 to pointer

poke pptr,word kdel 'Write the delay from last knock to storage area

kdel = 0 'Reset kdel ready for next knock

end if

next kdel

loop until kdel >= tmax 'If no knocks for over TMax loops then leave loop

'This section will operate sepending on the number of knocks detected.

'If there are no knocks it will exit.

'The maximum number of knocks is 23 to fill buffer. Incorrect count after that.

select case kcnt

case 0 'Do nothing if no knocks have occurred

case 21 'Put Box in 'Irritate Mode'.

gosub twoknock 'gosub twoknow to confirm routine was entered.

wait 10 'Do nothing for xx seconds

gosub twoknock

wait 9

gosub twoknock

wait 8

gosub twoknock

wait 7

gosub twoknock

wait 6

gosub twoknock

wait 5

gosub twoknock

wait 4

gosub twoknock

wait 3

gosub twoknock

wait 2

gosub twoknock

wait 1

gosub twoknock

else 'Any other number of knocks will be echoed

for tmp1 = 1 to kcnt 'Loop for the number of knocks

pptr = tmp1 * 2 + pstart 'Step in twos through buffer

peek pptr,word kdel 'Read back delay value words from buffer

pause kdel 'Wait the delay time (in milli-seconds)

gosub DoKnock 'Perform a knock

next tmp1 'Loop for next knock

pause 200

endselect

loop

'This section contains the knocking routines

DoKnock:

high knock 'Turn on motor

pause 70 'Wait 70 milli-seconds

low knock 'Turn off motor

return

TwoKnock: 'More compact to do this as subroutine

pause 550 'Two knocks with timed delays between for tune

gosub doknock

pause 700

gosub doknock

pause 700

return

"Echo Box" using PICAXE 08M (work in progress)

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Input is a SFE Piezo Element. Output is a DC motor driven by a 2N6284 Transistor (20A 100 V NPN Darlington). Controlled by PICAXE 08M.

The goal is to mount this in a box. When a user taps on the box, the box will echo the taps back.

Right now we are debugging the piezo input as it is not triggering reliably.

The piezo outputs between 1-2 Volts when it is hit; sometimes ringing with a negative voltage. Adding a 1M Ohm load to the piezo and an input protection diode should help. Also, lowering the voltage that powers the rig from 5V to 3V will help lower the input trigger threshold.

Stay tuned. As always, we will post the build details and source code at completion.

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Short vid of the current prototype. Working, but needing work...

PICAXE / MQ2 Gas Sensor Project in a Mouse

The project detects flammable gases (LPG, butane, propane, methane, methane, methane, methane, methane, alcohol, hydrogen, and methane.) via the MQ2 Gas Sensor. When a flammable gas is detected the frequency of the speaker beep increases. The whole enchilada is controlled by a PICAXE 08M uController and some custom code.

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Here is a video of the system operating. Keep reading if you want the details.

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The rig gets its power from a 5VDC USB port (Windows and Mac compatible ;) or a car USB charger). The MQ2 Gas Sensor is protected by a metal screen which can be seen in this photo of the finished product.

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Here is a shot of the circuit board powered up. In the final version we had to cut off the excess PCB material to make all the gear fit into the mouse. Note the "headphone input jack" near the top. That is actually a programming port allowing us to easily reprogram the PICAXE if we want to change the rigs personality. Such as, make the speaker beep faster, louder, flash lights, etc. Also, you can see that the PICAXE is not plugged into the socket yet. We wanted to check for solder shorts and smoke first to avoid damage to the PICAXE.

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Is all this stuff going to fit into the gutted mouse?

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Of course, if you watched the video above, you know it all fit (just barely). The build schematic:

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The source code for the PICAXE 08M is straightforward:

;

#picaxe08m

#com 11

main:

readadc C.2,b0 ; read the MQ2

sound B.1,(119,5) ; make a sound

w1 = 255 - b0

w1 = w1 * 5

pause w1 ; decrease pause between beeps if gas detected

goto main ; loop back to start

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That's it and thanks for checking out our build.

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